InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/gnu/regex-0.12/ChangeLog

Text File | 1993-04-02 | 136.4 KB | 3,031 lines

Fri Apr  2 17:31:59 1993  Jim Blandy  ([e-mail])

    * Released version 0.12.

    * regex.c (regerror): If errcode is zero, that's not a valid
    error code, according to POSIX, but return "Success."

    * regex.c (regerror): Remember to actually fetch the message
    from re_error_msg.

    * regex.c (regex_compile): Don't use the trick for ".*\n" on
    ".+\n".  Since the latter involves laying an extra choice
    point, the backward jump isn't adjusted properly.

Thu Mar 25 21:35:18 1993  Jim Blandy  ([e-mail])

    * regex.c (regex_compile): In the handle_open and handle_close
    sections, clear pending_exact to zero.

Tue Mar  9 12:03:07 1993  Jim Blandy  ([e-mail])

    * regex.c (re_search_2): In the loop which searches forward
    using fastmap, don't forget to cast the character from the
    string to an unsigned before using it as an index into the
    translate map.

Thu Jan 14 15:41:46 1993  David J. MacKenzie  ([e-mail])

    * regex.h: Never define const; let the callers do it.
    configure.in: Don't define USING_AUTOCONF.

Wed Jan  6 20:49:29 1993  Jim Blandy  ([e-mail])

    * regex.c (regerror): Abort if ERRCODE is out of range.

Sun Dec 20 16:19:10 1992  Jim Blandy  ([e-mail])

    * configure.in: Arrange to #define USING_AUTOCONF.
    * regex.h: If USING_AUTOCONF is #defined, don't mess with
    `const' at all; autoconf has taken care of it.

Mon Dec 14 21:40:39 1992  David J. MacKenzie  ([e-mail])

    * regex.h (RE_SYNTAX_AWK): Fix typo.  From Arnold Robbins.

Sun Dec 13 20:35:39 1992  Jim Blandy  ([e-mail])

        * regex.c (compile_range): Fetch the range start and end by
        casting the pattern pointer to an `unsigned char *' before
        fetching through it.

Sat Dec 12 09:41:01 1992  Jim Blandy  ([e-mail])

    * regex.c: Undo change of 12/7/92; it's better for Emacs to
    #define HAVE_CONFIG_H.

Fri Dec 11 22:00:34 1992  Jim Meyering ([e-mail])

    * regex.c: Define and use isascii-protected ctype.h macros.

Fri Dec 11 05:10:38 1992  Jim Blandy  ([e-mail])

    * regex.c (re_match_2): Undo Karl's November 10th change; it
    keeps the group in :\(.*\) from matching :/ properly.

Mon Dec  7 19:44:56 1992  Jim Blandy  ([e-mail])

    * regex.c: #include config.h if either HAVE_CONFIG_H or emacs
    is #defined.

Tue Dec  1 13:33:17 1992  David J. MacKenzie  ([e-mail])

    * regex.c [HAVE_CONFIG_H]: Include config.h.

Wed Nov 25 23:46:02 1992  David J. MacKenzie  ([e-mail])

    * regex.c (regcomp): Add parens around bitwise & for clarity.
    Initialize preg->allocated to prevent segv.

Tue Nov 24 09:22:29 1992  David J. MacKenzie  ([e-mail])

    * regex.c: Use HAVE_STRING_H, not USG.
    * configure.in: Check for string.h, not USG.

Fri Nov 20 06:33:24 1992  Karl Berry  ([e-mail])

        * regex.c (SIGN_EXTEND_CHAR) [VMS]: Back out of this change,
        since Roland Roberts now says it was a localism.

Mon Nov 16 07:01:36 1992  Karl Berry  ([e-mail])

        * regex.h (const) [!HAVE_CONST]: Test another cpp symbol (from
          Autoconf) before zapping const.

Sun Nov 15 05:36:42 1992  Jim Blandy  ([e-mail])

    * regex.c, regex.h: Changes for VMS from Roland B Roberts
    <[e-mail]>.

Thu Nov 12 11:31:15 1992  Karl Berry  ([e-mail])

        * Makefile.in (distfiles): Include INSTALL.

Tue Nov 10 09:29:23 1992  Karl Berry  ([e-mail])

        * regex.c (re_match_2): At maybe_pop_jump, if at end of string
          and pattern, just quit the matching loop.

        * regex.c (LETTER_P): Rename to `WORDCHAR_P'.

        * regex.c (AT_STRINGS_{BEG,END}): Take `d' as an arg; change
          callers.

        * regex.c (re_match_2) [!emacs]: In wordchar and notwordchar
          cases, advance d.

Wed Nov  4 15:43:58 1992  Karl Berry  ([e-mail])

        * regex.h (const) [!__STDC__]: Don't define if it's already defined.

Sat Oct 17 19:28:19 1992  Karl Berry  ([e-mail])

        * regex.c (bcmp, bcopy, bzero): Only #define if they are not
          already #defined.

        * configure.in: Use AC_CONST.

Thu Oct 15 08:39:06 1992  Karl Berry  ([e-mail])

        * regex.h (const) [!const]: Conditionalize.

Fri Oct  2 13:31:42 1992  Karl Berry  ([e-mail])

        * regex.h (RE_SYNTAX_ED): New definition.

Sun Sep 20 12:53:39 1992  Karl Berry  ([e-mail])

        * regex.[ch]: remove traces of `longest_p' -- dumb idea to put
          this into the pattern buffer, as it means parallelism loses.

        * Makefile.in (config.status): use sh to run configure --no-create.

        * Makefile.in (realclean): OK, don't remove configure.

Sat Sep 19 09:05:08 1992  Karl Berry  (karl@hayley)

        * regex.c (PUSH_FAILURE_POINT, POP_FAILURE_POINT) [DEBUG]: keep
          track of how many failure points we push and pop.
        (re_match_2) [DEBUG]: declare variables for that, and print results.
        (DEBUG_PRINT4): new macro.

        * regex.h (re_pattern_buffer): new field `longest_p' (to
          eliminate backtracking if the user doesn't need it).
        * regex.c (re_compile_pattern): initialize it (to 1).
        (re_search_2): set it to zero if register information is not needed.
        (re_match_2): if it's set, don't backtrack.

        * regex.c (re_search_2): update fastmap only after checking that
          the pattern is anchored.

        * regex.c (re_match_2): do more debugging at maybe_pop_jump.

        * regex.c (re_search_2): cast result of TRANSLATE for use in
          array subscript.

Thu Sep 17 19:47:16 1992  Karl Berry  ([e-mail])

        * Version 0.11.

Wed Sep 16 08:17:10 1992  Karl Berry  (karl@hayley)

        * regex.c (INIT_FAIL_STACK): rewrite as statements instead of a
          complicated comma expr, to avoid compiler warnings (and also
          simplify).
        (re_compile_fastmap, re_match_2): change callers.

        * regex.c (POP_FAILURE_POINT): cast pop of regstart and regend
          to avoid compiler warnings.

        * regex.h (RE_NEWLINE_ORDINARY): remove this syntax bit, and
          remove uses.
        * regex.c (at_{beg,end}line_loc_p): go the last mile: remove
          the RE_NEWLINE_ORDINARY case which made the ^ in \n^ be an anchor.

Tue Sep 15 09:55:29 1992  Karl Berry  (karl@hayley)

        * regex.c (at_begline_loc_p): new fn.
        (at_endline_loc_p): simplify at_endline_op_p.
        (regex_compile): in ^/$ cases, call the above.

        * regex.c (POP_FAILURE_POINT): rewrite the fn as a macro again,
          as lord's profiling indicates the function is 20% of the time.
        (re_match_2): callers changed.

        * configure.in (AC_MEMORY_H): remove, since we never use memcpy et al.

Mon Sep 14 17:49:27 1992  Karl Berry  (karl@hayley)

        * Makefile.in (makeargs): include MFLAGS.

Sun Sep 13 07:41:45 1992  Karl Berry  (karl@hayley)

        * regex.c (regex_compile): in \1..\9 case, make it always
          invalid to use \<digit> if there is no preceding <digit>th subexpr.
        * regex.h (RE_NO_MISSING_BK_REF): remove this syntax bit.

        * regex.c (regex_compile): remove support for invalid empty groups.
        * regex.h (RE_NO_EMPTY_GROUPS): remove this syntax bit.

        * regex.c (FREE_VARIABLES) [!REGEX_MALLOC]: define as alloca (0),
          to reclaim memory.

        * regex.h (RE_SYNTAX_POSIX_SED): don't bother with this.

Sat Sep 12 13:37:21 1992  Karl Berry  (karl@hayley)

        * README: incorporate emacs.diff.

        * regex.h (_RE_ARGS) [!__STDC__]: define as empty parens.

        * configure.in: add AC_ALLOCA.

        * Put test files in subdir test, documentation in subdir doc.
        Adjust Makefile.in and configure.in accordingly.

Thu Sep 10 10:29:11 1992  Karl Berry  (karl@hayley)

        * regex.h (RE_SYNTAX_{POSIX_,}SED): new definitions.

Wed Sep  9 06:27:09 1992  Karl Berry  (karl@hayley)

        * Version 0.10.

Tue Sep  8 07:32:30 1992  Karl Berry  (karl@hayley)

        * xregex.texinfo: put the day of month into the date.

        * Makefile.in (realclean): remove Texinfo-generated files.
        (distclean): remove empty sorted index files.
        (clean): remove dvi files, etc.

        * configure.in: test for more Unix variants.

        * fileregex.c: new file.
        Makefile.in (fileregex): new target.

        * iregex.c (main): move variable decls to smallest scope.

        * regex.c (FREE_VARIABLES): free reg_{,info_}dummy.
        (re_match_2): check that the allocation for those two succeeded.

        * regex.c (FREE_VAR): replace FREE_NONNULL with this.
        (FREE_VARIABLES): call it.
        (re_match_2) [REGEX_MALLOC]: initialize all our vars to NULL.

        * tregress.c (do_match): generalize simple_match.
        (SIMPLE_NONMATCH): new macro.
        (SIMPLE_MATCH): change from routine.

        * Makefile.in (regex.texinfo): make file readonly, so we don't
          edit it by mistake.

        * many files (re_default_syntax): rename to `re_syntax_options';
          call re_set_syntax instead of assigning to the variable where
          possible.

Mon Sep  7 10:12:16 1992  Karl Berry  (karl@hayley)

        * syntax.skel: don't use prototypes.

        * {configure,Makefile}.in: new files.

        * regex.c: include <string.h> `#if USG || STDC_HEADERS'; remove
          obsolete test for `POSIX', and test for BSRTING.
        Include <strings.h> if we are not USG or STDC_HEADERS.
        Do not include <unistd.h>.  What did we ever need that for?

        * regex.h (RE_NO_EMPTY_ALTS): remove this.
        (RE_SYNTAX_AWK): remove from here, too.
        * regex.c (regex_compile): remove the check.
        * xregex.texinfo (Alternation Operator): update.
        * other.c (test_others): remove tests for this.

        * regex.h (RE_DUP_MAX): undefine if already defined.

        * regex.h: (RE_SYNTAX_POSIX*): redo to allow more operators, and
          define new syntaxes with the minimal set.

        * syntax.skel (main): used sscanf instead of scanf.

        * regex.h (RE_SYNTAX_*GREP): new definitions from mike.

        * regex.c (regex_compile): initialize the upper bound of
          intervals at the beginning of the interval, not the end.
          (From [e-mail].)

        * regex.c (handle_bar): rename to `handle_alt', for consistency.

        * regex.c ({store,insert}_{op1,op2}): new routines (except the last).
        ({STORE,INSERT}_JUMP{,2}): macros to replace the old routines,
         which took arguments in different orders, and were generally weird.

        * regex.c (PAT_PUSH*): rename to `BUF_PUSH*' -- we're not
          appending info to the pattern!

Sun Sep  6 11:26:49 1992  Karl Berry  (karl@hayley)

        * regex.c (regex_compile): delete the variable
          `following_left_brace', since we never use it.

        * regex.c (print_compiled_pattern): don't print the fastmap if
          it's null.

        * regex.c (re_compile_fastmap): handle
          `on_failure_keep_string_jump' like `on_failure_jump'.

        * regex.c (re_match_2): in `charset{,_not' case, cast the bit
          count to unsigned, not unsigned char, in case we have a full
          32-byte bit list.

        * tregress.c (simple_match): remove.
        (simple_test): rename as `simple_match'.
        (simple_compile): print the error string if the compile failed.

        * regex.c (DO_RANGE): rewrite as a function, `compile_range', so
          we can debug it.  Change pattern characters to unsigned char
          *'s, and change the range variable to an unsigned.
        (regex_compile): change calls.

Sat Sep  5 17:40:49 1992  Karl Berry  (karl@hayley)

        * regex.h (_RE_ARGS): new macro to put in argument lists (if
          ANSI) or omit them (if K&R); don't declare routines twice.

        * many files (obscure_syntax): rename to `re_default_syntax'.

Fri Sep  4 09:06:53 1992  Karl Berry  (karl@hayley)

        * GNUmakefile (extraclean): new target.
        (realclean): delete the info files.

Wed Sep  2 08:14:42 1992  Karl Berry  (karl@hayley)

        * regex.h: doc fix.

Sun Aug 23 06:53:15 1992  Karl Berry  (karl@hayley)

        * regex.[ch] (re_comp): no const in the return type (from djm).

Fri Aug 14 07:25:46 1992  Karl Berry  (karl@hayley)

        * regex.c (DO_RANGE): declare variables as unsigned chars, not
          signed chars (from jimb).

Wed Jul 29 18:33:53 1992  Karl Berry  ([e-mail])

        * Version 0.9.

        * GNUmakefile (distclean): do not remove regex.texinfo.
        (realclean): remove it here.

        * tregress.c (simple_test): initialize buf.buffer.

Sun Jul 26 08:59:38 1992  Karl Berry  (karl@hayley)

        * regex.c (push_dummy_failure): new opcode and corresponding
          case in the various routines.  Pushed at the end of
          alternatives.

        * regex.c (jump_past_next_alt): rename to `jump_past_alt', for
          brevity.
        (no_pop_jump): rename to `jump'.

        * regex.c (regex_compile) [DEBUG]: terminate printing of pattern
          with a newline.

        * NEWS: new file.

        * tregress.c (simple_{compile,match,test}): routines to simplify all
          these little tests.

        * tregress.c: test for matching as much as possible.

Fri Jul 10 06:53:32 1992  Karl Berry  (karl@hayley)

        * Version 0.8.

Wed Jul  8 06:39:31 1992  Karl Berry  (karl@hayley)

        * regex.c (SIGN_EXTEND_CHAR): #undef any previous definition, as
          ours should always work properly.

Mon Jul  6 07:10:50 1992  Karl Berry  (karl@hayley)

        * iregex.c (main) [DEBUG]: conditionalize the call to
          print_compiled_pattern.

        * iregex.c (main): initialize buf.buffer to NULL.
        * tregress (test_regress): likewise.

        * regex.c (alloca) [sparc]: #if on HAVE_ALLOCA_H instead.

        * tregress.c (test_regress): didn't have jla's test quite right.

Sat Jul  4 09:02:12 1992  Karl Berry  (karl@hayley)

        * regex.c (re_match_2): only REGEX_ALLOCATE all the register
          vectors if the pattern actually has registers.
        (match_end): new variable to avoid having to use best_regend[0].

        * regex.c (IS_IN_FIRST_STRING): rename to FIRST_STRING_P.

        * regex.c: doc fixes.

        * tregess.c (test_regress): new fastmap test forwarded by rms.

        * tregress.c (test_regress): initialize the fastmap field.

        * tregress.c (test_regress): new test from jla that aborted
          in re_search_2.

Fri Jul  3 09:10:05 1992  Karl Berry  (karl@hayley)

        * tregress.c (test_regress): add tests for translating charsets,
          from kaoru.

        * GNUmakefile (common): add alloca.o.
        * alloca.c: new file, copied from bison.

        * other.c (test_others): remove var `buf', since it's no longer used.

    * Below changes from [e-mail].

        * tregress.c (test_regress): initialize buf.allocated.

        * regex.c (re_compile_fastmap): initialize `succeed_n_p'.

        * GNUmakefile (regex): depend on $(common).

Wed Jul  1 07:12:46 1992  Karl Berry  (karl@hayley)

        * Version 0.7.

        * regex.c: doc fixes.

Mon Jun 29 08:09:47 1992  Karl Berry  (karl@fosse)

        * regex.c (pop_failure_point): change string vars to
    `const char *' from `unsigned char *'.

        * regex.c: consolidate debugging stuff.
        (print_partial_compiled_pattern): avoid enum clash.

Mon Jun 29 07:50:27 1992  Karl Berry  (karl@hayley)

        * xmalloc.c: new file.
        * GNUmakefile (common): add it.

        * iregex.c (print_regs): new routine (from jimb).
        (main): call it.

Sat Jun 27 10:50:59 1992  Jim Blandy  ([e-mail])

    * xregex.c (re_match_2): When we have accepted a match and
    restored d from best_regend[0], we need to set dend
    appropriately as well.

Sun Jun 28 08:48:41 1992  Karl Berry  (karl@hayley)

        * tregress.c: rename from regress.c.

        * regex.c (print_compiled_pattern): improve charset case to ease
            byte-counting.
          Also, don't distinguish between Emacs and non-Emacs
           {not,}wordchar opcodes.

        * regex.c (print_fastmap): move here.
        * test.c: from here.
        * regex.c (print_{{partial,}compiled_pattern,double_string}):
          rename from ..._printer.  Change calls here and in test.c.

        * regex.c: create from xregex.c and regexinc.c for once and for
          all, and change the debug fns to be extern, instead of static.
        * GNUmakefile: remove traces of xregex.c.
        * test.c: put in externs, instead of including regexinc.c.

        * xregex.c: move interactive main program and scanstring to iregex.c.
        * iregex.c: new file.
        * upcase.c, printchar.c: new files.

        * various doc fixes and other cosmetic changes throughout.

        * regexinc.c (compiled_pattern_printer): change variable name,
          for consistency.
        (partial_compiled_pattern_printer): print other info about the
          compiled pattern, besides just the opcodes.
        * xregex.c (regex_compile) [DEBUG]: print the compiled pattern
          when we're done.

        * xregex.c (re_compile_fastmap): in the duplicate case, set
            `can_be_null' and return.
          Also, set `bufp->can_be_null' according to a new variable,
            `path_can_be_null'.
          Also, rewrite main while loop to not test `p != NULL', since
            we never set it that way.
          Also, eliminate special `can_be_null' value for the endline case.
        (re_search_2): don't test for the special value.
       * regex.h (struct re_pattern_buffer): remove the definition.

Sat Jun 27 15:00:40 1992  Karl Berry  (karl@hayley)

        * xregex.c (re_compile_fastmap): remove the `RE_' from
            `REG_RE_MATCH_NULL_AT_END'.
          Also, assert the fastmap in the pattern buffer is non-null.
          Also, reset `succeed_n_p' after we've
            paid attention to it, instead of every time through the loop.
          Also, in the `anychar' case, only clear fastmap['\n'] if the
           syntax says to, and don't return prematurely.
          Also, rearrange cases in some semblance of a rational order.
        * regex.h (REG_RE_MATCH_NULL_AT_END): remove the `RE_' from the name.

        * other.c: take bug reports from here.
        * regress.c: new file for them.
        * GNUmakefile (test): add it.
        * main.c (main): new possible test.
        * test.h (test_type): new value in enum.

Thu Jun 25 17:37:43 1992  Karl Berry  (karl@hayley)

        * xregex.c (scanstring) [test]: new function from jimb to allow some
          escapes.
        (main) [test]: call it (on the string, not the pattern).

        * xregex.c (main): make return type `int'.

Wed Jun 24 10:43:03 1992  Karl Berry  (karl@hayley)

        * xregex.c (pattern_offset_t): change to `int', for the benefit
          of patterns which compile to more than 2^15 bytes.

        * xregex.c (GET_BUFFER_SPACE): remove spurious braces.

        * xregex.texinfo (Using Registers): put in a stub to ``document''
          the new function.
        * regex.h (re_set_registers) [!__STDC__]: declare.
        * xregex.c (re_set_registers): declare K&R style (also move to a
          different place in the file).

Mon Jun  8 18:03:28 1992  Jim Blandy  ([e-mail])

    * regex.h (RE_NREGS): Doc fix.

    * xregex.c (re_set_registers): New function.
    * regex.h (re_set_registers): Declaration for new function.

Fri Jun  5 06:55:18 1992  Karl Berry  (karl@hayley)

        * main.c (main): `return 0' instead of `exit (0)'.  (From Paul Eggert)

        * regexinc.c (SIGN_EXTEND_CHAR): cast to unsigned char.
        (extract_number, EXTRACT_NUMBER): don't bother to cast here.

Tue Jun  2 07:37:53 1992  Karl Berry  (karl@hayley)

        * Version 0.6.

        * Change copyrights to `1985, 89, ...'.

        * regex.h (REG_RE_MATCH_NULL_AT_END): new macro.
        * xregex.c (re_compile_fastmap): initialize `can_be_null' to
          `p==pend', instead of in the test at the top of the loop (as
          it was, it was always being set).
          Also, set `can_be_null'=1 if we would jump to the end of the
            pattern in the `on_failure_jump' cases.
        (re_search_2): check if `can_be_null' is 1, not nonzero.  This
          was the original test in rms' regex; why did we change this?

        * xregex.c (re_compile_fastmap): rename `is_a_succeed_n' to
          `succeed_n_p'.

Sat May 30 08:09:08 1992  Karl Berry  (karl@hayley)

        * xregex.c (re_compile_pattern): declare `regnum' as `unsigned',
          not `regnum_t', for the benefit of those patterns with more
          than 255 groups.

        * xregex.c: rename `failure_stack' to `fail_stack', for brevity;
          likewise for `match_nothing' to `match_null'.

        * regexinc.c (REGEX_REALLOCATE): take both the new and old
          sizes, and copy only the old bytes.
        * xregex.c (DOUBLE_FAILURE_STACK): pass both old and new.
        * This change from Thorsten Ohl.

Fri May 29 11:45:22 1992  Karl Berry  (karl@hayley)

        * regexinc.c (SIGN_EXTEND_CHAR): define as `(signed char) c'
          instead of relying on __CHAR_UNSIGNED__, to work with
          compilers other than GCC.  From Per Bothner.

        * main.c (main): change return type to `int'.

Mon May 18 06:37:08 1992  Karl Berry  (karl@hayley)

        * regex.h (RE_SYNTAX_AWK): typo in RE_RE_UNMATCHED...

Fri May 15 10:44:46 1992  Karl Berry  (karl@hayley)

        * Version 0.5.

Sun May  3 13:54:00 1992  Karl Berry  (karl@hayley)

        * regex.h (struct re_pattern_buffer): now it's just `regs_allocated'.
        (REGS_UNALLOCATED, REGS_REALLOCATE, REGS_FIXED): new constants.
        * xregex.c (regexec, re_compile_pattern): set the field appropriately.
        (re_match_2): and use it.  bufp can't be const any more.

Fri May  1 15:43:09 1992  Karl Berry  (karl@hayley)

        * regexinc.c: unconditionally include <sys/types.h>, first.

        * regex.h (struct re_pattern_buffer): rename
          `caller_allocated_regs' to `regs_allocated_p'.
        * xregex.c (re_compile_pattern): same change here.
        (regexec): and here.
        (re_match_2): reallocate registers if necessary.

Fri Apr 10 07:46:50 1992  Karl Berry  (karl@hayley)

        * regex.h (RE_SYNTAX{_POSIX,}_AWK): new definitions from Arnold.

Sun Mar 15 07:34:30 1992  Karl Berry  (karl at hayley)

        * GNUmakefile (dist): versionize regex.{c,h,texinfo}.

Tue Mar 10 07:05:38 1992  Karl Berry  (karl at hayley)

        * Version 0.4.

        * xregex.c (PUSH_FAILURE_POINT): always increment the failure id.
        (DEBUG_STATEMENT) [DEBUG]: execute the statement even if `debug'==0.

        * xregex.c (pop_failure_point): if the saved string location is
          null, keep the current value.
        (re_match_2): at fail, test for a dummy failure point by
          checking the restored pattern value, not string value.
        (re_match_2): new case, `on_failure_keep_string_jump'.
        (regex_compile): output this opcode in the .*\n case.
        * regexinc.c (re_opcode_t): define the opcode.
        (partial_compiled_pattern_pattern): add the new case.

Mon Mar  9 09:09:27 1992  Karl Berry  (karl at hayley)

        * xregex.c (regex_compile): optimize .*\n to output an
          unconditional jump to the ., instead of pushing failure points
          each time through the loop.

        * xregex.c (DOUBLE_FAILURE_STACK): compute the maximum size
          ourselves (and correctly); change callers.

Sun Mar  8 17:07:46 1992  Karl Berry  (karl at hayley)

        * xregex.c (failure_stack_elt_t): change to `const char *', to
          avoid warnings.

        * regex.h (re_set_syntax): declare this.

        * xregex.c (pop_failure_point) [DEBUG]: conditionally pass the
          original strings and sizes; change callers.

Thu Mar  5 16:35:35 1992  Karl Berry  (karl at claude.cs.umb.edu)

        * xregex.c (regnum_t): new type for register/group numbers.
        (compile_stack_elt_t, regex_compile): use it.

        * xregex.c (regexec): declare len as `int' to match re_search.

        * xregex.c (re_match_2): don't declare p1 twice.

        * xregex.c: change `while (1)' to `for (;;)' to avoid silly
          compiler warnings.

        * regex.h [__STDC__]: use #if, not #ifdef.

        * regexinc.c (REGEX_REALLOCATE): cast the result of alloca to
          (char *), to avoid warnings.

        * xregex.c (regerror): declare variable as const.

        * xregex.c (re_compile_pattern, re_comp): define as returning a const
          char *.
        * regex.h (re_compile_pattern, re_comp): likewise.

Thu Mar  5 15:57:56 1992  Karl Berry  (karl@hal)

        * xregex.c (regcomp): declare `syntax' as unsigned.

        * xregex.c (re_match_2): try to avoid compiler warnings about
          unsigned comparisons.

        * GNUmakefile (test-xlc): new target.

        * regex.h (reg_errcode_t): remove trailing comma from definition.
        * regexinc.c (re_opcode_t): likewise.

Thu Mar  5 06:56:07 1992  Karl Berry  (karl at hayley)

        * GNUmakefile (dist): add version numbers automatically.
        (versionfiles): new variable.
        (regex.{c,texinfo}): don't add version numbers here.
        * regex.h: put in placeholder instead of the version number.

Fri Feb 28 07:11:33 1992  Karl Berry  (karl at hayley)

        * xregex.c (re_error_msg): declare const, since it is.

Sun Feb 23 05:41:57 1992  Karl Berry  (karl at fosse)

        * xregex.c (PAT_PUSH{,_2,_3}, ...): cast args to avoid warnings.
        (regex_compile, regexec): return REG_NOERROR, instead
          of 0, on success.
        (boolean): define as char, and #define false and true.
        * regexinc.c (STREQ): cast the result.

Sun Feb 23 07:45:38 1992  Karl Berry  (karl at hayley)

        * GNUmakefile (test-cc, test-hc, test-pcc): new targets.

        * regex.inc (extract_number, extract_number_and_incr) [DEBUG]:
          only define if we are debugging.

        * xregex.c [_AIX]: do #pragma alloca first if necessary.
        * regexinc.c [_AIX]: remove the #pragma from here.

        * regex.h (reg_syntax_t): declare as unsigned, and redo the enum
          as #define's again.  Some compilers do stupid things with enums.

Thu Feb 20 07:19:47 1992  Karl Berry  (karl at hayley)

        * Version 0.3.

        * xregex.c, regex.h (newline_anchor_match_p): rename to
          `newline_anchor'; dumb idea to change the name.

Tue Feb 18 07:09:02 1992  Karl Berry  (karl at hayley)

        * regexinc.c: go back to original, i.e., don't include
          <string.h> or define strchr.
        * xregex.c (regexec): don't bother with adding characters after
          newlines to the fastmap; instead, just don't use a fastmap.
        * xregex.c (regcomp): set the buffer and fastmap fields to zero.

        * xregex.texinfo (GNU r.e. compiling): have to initialize more
          than two fields.

        * regex.h (struct re_pattern_buffer): rename `newline_anchor' to
          `newline_anchor_match_p', as we're back to two cases.
        * xregex.c (regcomp, re_compile_pattern, re_comp): change
          accordingly.
        (re_match_2): at begline and endline, POSIX is not a special
          case anymore; just check newline_anchor_match_p.

Thu Feb 13 16:29:33 1992  Karl Berry  (karl at hayley)

        * xregex.c (*empty_string*): rename to *null_string*, for brevity.

Wed Feb 12 06:36:22 1992  Karl Berry  (karl at hayley)

        * xregex.c (re_compile_fastmap): at endline, don't set fastmap['\n'].
        (re_match_2): rewrite the begline/endline cases to take account
          of the new field newline_anchor.

Tue Feb 11 14:34:55 1992  Karl Berry  (karl at hayley)

        * regexinc.c [!USG etc.]: include <strings.h> and define strchr
          as index.

        * xregex.c (re_search_2): when searching backwards, declare `c'
          as a char and use casts when using it as an array subscript.

        * xregex.c (regcomp): if REG_NEWLINE, set
          RE_HAT_LISTS_NOT_NEWLINE.  Set the `newline_anchor' field
          appropriately.
        (regex_compile): compile [^...] as matching a \n according to
          the syntax bit.
        (regexec): if doing REG_NEWLINE stuff, compile a fastmap and add
          characters after any \n's to the newline.
        * regex.h (RE_HAT_LISTS_NOT_NEWLINE): new syntax bit.
        (struct re_pattern_buffer): rename `posix_newline' to
          `newline_anchor', define constants for its values.

Mon Feb 10 07:22:50 1992  Karl Berry  (karl at hayley)

        * xregex.c (re_compile_fastmap): combine the code at the top and
          bottom of the loop, as it's essentially identical.

Sun Feb  9 10:02:19 1992  Karl Berry  (karl at hayley)

        * xregex.texinfo (POSIX Translate Tables): remove this, as it
          doesn't match the spec.

        * xregex.c (re_compile_fastmap): if we finish off a path, go
          back to the top (to set can_be_null) instead of returning
          immediately.

        * xregex.texinfo: changes from bob.

Sat Feb  1 07:03:25 1992  Karl Berry  (karl at hayley)

        * xregex.c (re_search_2): doc fix (from rms).

Fri Jan 31 09:52:04 1992  Karl Berry  (karl at hayley)

        * xregex.texinfo (GNU Searching): clarify the range arg.

        * xregex.c (re_match_2, at_endline_op_p): add extra parens to
          get rid of GCC 2's (silly, IMHO) warning about && within ||.

        * xregex.c (common_op_match_empty_string_p): use
          MATCH_NOTHING_UNSET_VALUE, not -1.

Thu Jan 16 08:43:02 1992  Karl Berry  (karl at hayley)

        * xregex.c (SET_REGS_MATCHED): only set the registers from
          lowest to highest.

        * regexinc.c (MIN): new macro.
        * xregex.c (re_match_2): only check min (num_regs,
          regs->num_regs) when we set the returned regs.

        * xregex.c (re_match_2): set registers after the first
          num_regs to -1 before we return.

Tue Jan 14 16:01:42 1992  Karl Berry  (karl at hayley)

        * xregex.c (re_match_2): initialize max (RE_NREGS, re_nsub + 1)
          registers (from rms).

        * xregex.c, regex.h: don't abbreviate `19xx' to `xx'.

        * regexinc.c [!emacs]: include <sys/types.h> before <unistd.h>.
          (from [e-mail]).

Thu Jan  9 07:23:00 1992  Karl Berry  (karl at hayley)

        * xregex.c (*unmatchable): rename to `match_empty_string_p'.
        (CAN_MATCH_NOTHING): rename to `REG_MATCH_EMPTY_STRING_P'.

        * regexinc.c (malloc, realloc): remove prototypes, as they can
          cause clashes (from rms).

Mon Jan  6 12:43:24 1992  Karl Berry  (karl at claude.cs.umb.edu)

        * Version 0.2.

Sun Jan  5 10:50:38 1992  Karl Berry  (karl at hayley)

        * xregex.texinfo: bring more or less up-to-date.
        * GNUmakefile (regex.texinfo): generate from regex.h and
          xregex.texinfo.
        * include.awk: new file.

        * xregex.c: change all calls to the fn extract_number_and_incr
          to the macro.

        * xregex.c (re_match_2) [emacs]: in at_dot, use PTR_CHAR_POS + 1,
          instead of bf_* and sl_*.  Cast d to unsigned char *, to match
          the declaration in Emacs' buffer.h.
        [emacs19]: in before_dot, at_dot, and after_dot, likewise.

        * regexinc.c: unconditionally include <sys/types.h>.

        * regexinc.c (alloca) [!alloca]: Emacs config files sometimes
          define this, so don't define it if it's already defined.

Sun Jan  5 06:06:53 1992  Karl Berry  (karl at fosse)

        * xregex.c (re_comp): fix type conflicts with regex_compile (we
          haven't been compiling this).

        * regexinc.c (SIGN_EXTEND_CHAR): use `__CHAR_UNSIGNED__', not
          `CHAR_UNSIGNED'.

        * regexinc.c (NULL) [!NULL]: define it (as zero).

        * regexinc.c (extract_number): remove the temporaries.

Sun Jan  5 07:50:14 1992  Karl Berry  (karl at hayley)

        * regex.h (regerror) [!__STDC__]: return a size_t, not a size_t *.

        * xregex.c (PUSH_FAILURE_POINT, ...): declare `destination' as
          `char *' instead of `void *', to match alloca declaration.

        * xregex.c (regerror): use `size_t' for the intermediate values
          as well as the return type.

        * xregex.c (regexec): cast the result of malloc.

        * xregex.c (regexec): don't initialize `private_preg' in the
          declaration, as old C compilers can't do that.

        * xregex.c (main) [test]: declare printchar void.

        * xregex.c (assert) [!DEBUG]: define this to do nothing, and
          remove #ifdef DEBUG's from around asserts.

        * xregex.c (re_match_2): remove error message when not debugging.

Sat Jan  4 09:45:29 1992  Karl Berry  (karl at hayley)

        * other.c: test the bizarre duplicate case in re_compile_fastmap
          that I just noticed.

        * test.c (general_test): don't test registers beyond the end of
          correct_regs, as well as regs.

        * xregex.c (regex_compile): at handle_close, don't assign to
          *inner_group_loc if we didn't push a start_memory (because the
          group number was too big).  In fact, don't push or pop the
          inner_group_offset in that case.

        * regex.c: rename to xregex.c, since it's not the whole thing.
        * regex.texinfo: likewise.
        * GNUmakefile: change to match.

        * regex.c [DEBUG]: only include <stdio.h> if debugging.

        * regexinc.c (SIGN_EXTEND_CHAR) [CHAR_UNSIGNED]: if it's already
          defined, don't redefine it.

        * regex.c: define _GNU_SOURCE at the beginning.
        * regexinc.c (isblank) [!isblank]: define it.
        (isgraph) [!isgraph]: change conditional to this, and remove the
          sequent stuff.

        * regex.c (regex_compile): add `blank' character class.

        * regex.c (regex_compile): don't use a uchar variable to loop
          through all characters.

        * regex.c (regex_compile): at '[', improve logic for checking
          that we have enough space for the charset.

        * regex.h (struct re_pattern_buffer): declare translate as char
          * again.  We only use it as an array subscript once, I think.

        * regex.c (TRANSLATE): new macro to cast the data character
          before subscripting.
        (num_internal_regs): rename to `num_regs'.

Fri Jan  3 07:58:01 1992  Karl Berry  (karl at hayley)

        * regex.h (struct re_pattern_buffer): declare `allocated' and
          `used' as unsigned long, since these are never negative.

        * regex.c (compile_stack_element): rename to compile_stack_elt_t.
        (failure_stack_element): similarly.

        * regexinc.c (TALLOC, RETALLOC): new macros to simplify
          allocation of arrays.

        * regex.h (re_*) [__STDC__]: don't declare string args unsigned
          char *; that makes them incompatible with string constants.
        (struct re_pattern_buffer): declare the pattern and translate
          table as unsigned char *.
        * regex.c (most routines): use unsigned char vs. char consistently.

        * regex.h (re_compile_pattern): do not declare the length arg as
          const.
        * regex.c (re_compile_pattern): likewise.

        * regex.c (POINTER_TO_REG): rename to `POINTER_TO_OFFSET'.

        * regex.h (re_registers): declare `start' and `end' as
          `regoff_t', instead of `int'.

        * regex.c (regexec): if either of the malloc's for the register
          information fail, return failure.

        * regex.h (RE_NREGS): define this again, as 30 (from jla).
        (RE_ALLOCATE_REGISTERS): remove this.
        (RE_SYNTAX_*): remove it from definitions.
        (re_pattern_buffer): remove `return_default_num_regs', add
          `caller_allocated_regs'.
        * regex.c (re_compile_pattern): clear no_sub and
          caller_allocated_regs in the pattern.
        (regcomp): set caller_allocated_regs.
        (re_match_2): do all register allocation at the end of the
          match; implement new semantics.

        * regex.c (MAX_REGNUM): new macro.
        (regex_compile): at handle_open and handle_close, if the group
          number is too large, don't push the start/stop memory.

Thu Jan  2 07:56:10 1992  Karl Berry  (karl at hayley)

        * regex.c (re_match_2): if the back reference is to a group that
          never matched, then goto fail, not really_fail.  Also, don't
          test if the pattern can match the empty string.  Why did we
          ever do that?
        (really_fail): this label no longer needed.

        * regexinc.c [STDC_HEADERS]: use only this to test if we should
          include <stdlib.h>.

        * regex.c (DO_RANGE, regex_compile): translate in all cases
          except the single character after a \.

        * regex.h (RE_AWK_CLASS_HACK): rename to
          RE_BACKSLASH_ESCAPE_IN_LISTS.
        * regex.c (regex_compile): change use.

        * regex.c (re_compile_fastmap): do not translate the characters
          again; we already translated them at compilation.  (From [e-mail].)

        * regex.c (re_match_2): in case for at_dot, invert sense of
          comparison and find the character number properly.  (From
          [e-mail].)
        (re_match_2) [emacs]: remove the cases for before_dot and
          after_dot, since there's no way to specify them, and the code
          is wrong (judging from this change).

Wed Jan  1 09:13:38 1992  Karl Berry  (karl at hayley)

        * psx-{interf,basic,extend}.c, other.c: set `t' as the first
          thing, so that if we run them in sucession, general_test's
          kludge to see if we're doing POSIX tests works.

        * test.h (test_type): add `all_test'.
        * main.c: add case for `all_test'.

        * regexinc.c (partial_compiled_pattern_printer,
          double_string_printer): don't print anything if we're passed null.

        * regex.c (PUSH_FAILURE_POINT): do not scan for the highest and
          lowest active registers.
        (re_match_2): compute lowest/highest active regs at start_memory and
          stop_memory.
        (NO_{LOW,HIGH}EST_ACTIVE_REG): new sentinel values.
        (pop_failure_point): return the lowest/highest active reg values
          popped; change calls.

        * regex.c [DEBUG]: include <assert.h>.
        (various routines) [DEBUG]: change conditionals to assertions.

        * regex.c (DEBUG_STATEMENT): new macro.
        (PUSH_FAILURE_POINT): use it to increment num_regs_pushed.
        (re_match_2) [DEBUG]: only declare num_regs_pushed if DEBUG.

        * regex.c (*can_match_nothing): rename to *unmatchable.

        * regex.c (re_match_2): at stop_memory, adjust argument reading.

        * regex.h (re_pattern_buffer): declare `can_be_null' as a 2-bit
          bit field.

        * regex.h (re_pattern_buffer): declare `buffer' unsigned char *;
          no, dumb idea.  The pattern can have signed number.

        * regex.c (re_match_2): in maybe_pop_jump case, skip over the
          right number of args to the group operators, and don't do
          anything with endline if posix_newline is not set.

        * regex.c, regexinc.c (all the things we just changed): go back
          to putting the inner group count after the start_memory,
          because we need it in the on_failure_jump case in re_match_2.
          But leave it after the stop_memory also, since we need it
          there in re_match_2, and we don't have any way of getting back
          to the start_memory.

        * regexinc.c (partial_compiled_pattern_printer): adjust argument
          reading for start/stop_memory.
        * regex.c (re_compile_fastmap, group_can_match_nothing): likewise.

Tue Dec 31 10:15:08 1991  Karl Berry  (karl at hayley)

        * regex.c (bits list routines): remove these.
        (re_match_2): get the number of inner groups from the pattern,
          instead of keeping track of it at start and stop_memory.
          Put the count after the stop_memory, not after the
          start_memory.
        (compile_stack_element): remove `fixup_inner_group' member,
          since we now put it in when we can compute it.
        (regex_compile): at handle_open, don't push the inner group
          offset, and at handle_close, don't pop it.

        * regex.c (level routines): remove these, and their uses in
          regex_compile.  This was another manifestation of having to find
          $'s that were endlines.

        * regex.c (regexec): this does searching, not matching (a
          well-disguised part of the standard).  So rewrite to use
          `re_search' instead of `re_match'.
        * psx-interf.c (test_regexec): add tests to, uh, match.

        * regex.h (RE_TIGHT_ALT): remove this; nobody uses it.
        * regex.c: remove the code that was supposed to implement it.

        * other.c (test_others): ^ and $ never match newline characters;
          RE_CONTEXT_INVALID_OPS doesn't affect anchors.

        * psx-interf.c (test_regerror): update for new error messages.

        * psx-extend.c: it's now ok to have an alternative be just a $,
          so remove all the tests which supposed that was invalid.

Wed Dec 25 09:00:05 1991  Karl Berry  (karl at hayley)

        * regex.c (regex_compile): in handle_open, don't skip over ^ and
          $ when checking for an empty group.  POSIX has changed the
          grammar.
        * psx-extend.c (test_posix_extended): thus, move (^$) tests to
          valid section.

        * regexinc.c (boolean): move from here to test.h and regex.c.
        * test files: declare verbose, omit_register_tests, and
          test_should_match as boolean.

        * psx-interf.c (test_posix_c_interface): remove the `c_'.
        * main.c: likewise.

        * psx-basic.c (test_posix_basic): ^ ($) is an anchor after
          (before) an open (close) group.

        * regex.c (re_match_2): in endline, correct precedence of
          posix_newline condition.

Tue Dec 24 06:45:11 1991  Karl Berry  (karl at hayley)

        * test.h: incorporate private-tst.h.
        * test files: include test.h, not private-tst.h.

        * test.c (general_test): set posix_newline to zero if we are
          doing POSIX tests (unfortunately, it's difficult to call
          regcomp in this case, which is what we should really be doing).

        * regex.h (reg_syntax_t): make this an enumeration type which
          defines the syntax bits; renames re_syntax_t.

        * regex.c (at_endline_op_p): don't preincrement p; then if it's
          not an empty string op, we lose.

        * regex.h (reg_errcode_t): new enumeration type of the error
          codes.
        * regex.c (regex_compile): return that type.

        * regex.c (regex_compile): in [, initialize
          just_had_a_char_class to false; somehow I had changed this to
          true.

        * regex.h (RE_NO_CONSECUTIVE_REPEATS): remove this, since we
          don't use it, and POSIX doesn't require this behavior anymore.
        * regex.c (regex_compile): remove it from here.

        * regex.c (regex_compile): remove the no_op insertions for
          verify_and_adjust_endlines, since that doesn't exist anymore.

        * regex.c (regex_compile) [DEBUG]: use printchar to print the
          pattern, so unprintable bytes will print properly.

        * regex.c: move re_error_msg back.
        * test.c (general_test): print the compile error if the pattern
          was invalid.

Mon Dec 23 08:54:53 1991  Karl Berry  (karl at hayley)

        * regexinc.c: move re_error_msg here.

        * regex.c (re_error_msg): the ``message'' for success must be
          NULL, to keep the interface to re_compile_pattern the same.
        (regerror): if the msg is null, use "Success".

        * rename most test files for consistency.  Change Makefile
          correspondingly.

        * test.c (most routines): add casts to (unsigned char *) when we
          call re_{match,search}{,_2}.

Sun Dec 22 09:26:06 1991  Karl Berry  (karl at hayley)

        * regex.c (re_match_2): declare string args as unsigned char *
          again; don't declare non-pointer args const; declare the
          pattern buffer const.
        (re_match): likewise.
        (re_search_2, re_search): likewise, except don't declare the
          pattern const, since we make a fastmap.
        * regex.h [__STDC__]: change prototypes.

        * regex.c (regex_compile): return an error code, not a string.
        (re_err_list): new table to map from error codes to string.
        (re_compile_pattern): return an element of re_err_list.
        (regcomp): don't test all the strings.
        (regerror): just use the list.
        (put_in_buffer): remove this.

        * regex.c (equivalent_failure_points): remove this.

        * regex.c (re_match_2): don't copy the string arguments into
          non-const pointers.  We never alter the data.

        * regex.c (re_match_2): move assignment to `is_a_jump_n' out of
          the main loop.  Just initialize it right before we do
          something with it.

        * regex.[ch] (re_match_2): don't declare the int parameters const.

Sat Dec 21 08:52:20 1991  Karl Berry  (karl at hayley)

        * regex.h (re_syntax_t): new type; declare to be unsigned
          (previously we used int, but since we do bit operations on
          this, unsigned is better, according to H&S).
        (obscure_syntax, re_pattern_buffer): use that type.
        * regex.c (re_set_syntax, regex_compile): likewise.

        * regex.h (re_pattern_buffer): new field `posix_newline'.
        * regex.c (re_comp, re_compile_pattern): set to zero.
        (regcomp): set to REG_NEWLINE.
        * regex.h (RE_HAT_LISTS_NOT_NEWLINE): remove this (we can just
          check `posix_newline' instead.)

        * regex.c (op_list_type, op_list, add_op): remove these.
        (verify_and_adjust_endlines): remove this.
        (pattern_offset_list_type, *pattern_offset* routines): and these.
          These things all implemented the nonleading/nontrailing position
          code, which was very long, had a few remaining problems, and
          is no longer needed.  So...

        * regexinc.c (STREQ): new macro to abbreviate strcmp(,)==0, for
          brevity.  Change various places in regex.c to use it.

        * regex{,inc}.c (enum regexpcode): change to a typedef
          re_opcode_t, for brevity.

        * regex.h (re_syntax_table) [SYNTAX_TABLE]: remove this; it
          should only be in regex.c, I think, since we don't define it
          in this case.  Maybe it should be conditional on !SYNTAX_TABLE?

        * regexinc.c (partial_compiled_pattern_printer): simplify and
          distinguish the emacs/not-emacs (not)wordchar cases.

Fri Dec 20 08:11:38 1991  Karl Berry  (karl at hayley)

        * regexinc.c (regexpcode) [emacs]: only define the Emacs opcodes
          if we are ifdef emacs.

        * regex.c (BUF_PUSH*): rename to PAT_PUSH*.

        * regex.c (regex_compile): in $ case, go back to essentially the
          original code for deciding endline op vs. normal char.
        (at_endline_op_p): new routine.
        * regex.h (RE_ANCHORS_ONLY_AT_ENDS, RE_CONTEXT_INVALID_ANCHORS,
          RE_REPEATED_ANCHORS_AWAY, RE_NO_ANCHOR_AT_NEWLINE): remove
          these.  POSIX has simplified the rules for anchors in draft
          11.2.
        (RE_NEWLINE_ORDINARY): new syntax bit.
        (RE_CONTEXT_INDEP_ANCHORS): change description to be compatible
          with POSIX.
        * regex.texinfo (Syntax Bits): remove the descriptions.

Mon Dec 16 08:12:40 1991  Karl Berry  (karl at hayley)

        * regex.c (re_match_2): in jump_past_next_alt, unconditionally
          goto no_pop.  The only register we were finding was one which
          enclosed the whole alternative expression, not one around an
          individual alternative.  So we were never doing what we
          thought we were doing, and this way makes (|a) against the
          empty string fail.

        * regex.c (regex_compile): remove `highest_ever_regnum', and
          don't restore regnum from the stack; just put it into a
          temporary to put into the stop_memory.  Otherwise, groups
          aren't numbered consecutively.

        * regex.c (is_in_compile_stack): rename to
          `group_in_compile_stack'; remove unnecessary test for the
          stack being empty.

        * regex.c (re_match_2): in on_failure_jump, skip no_op's before
          checking for the start_memory, in case we were called from
          succeed_n.

Sun Dec 15 16:20:48 1991  Karl Berry  (karl at hayley)

        * regex.c (regex_compile): in duplicate case, use
          highest_ever_regnum instead of regnum, since the latter is
          reverted at stop_memory.

        * regex.c (re_match_2): in on_failure_jump, if the * applied to
          a group, save the information for that group and all inner
          groups (by making it active), even though we're not inside it
          yet.

Sat Dec 14 09:50:59 1991  Karl Berry  (karl at hayley)

        * regex.c (PUSH_FAILURE_ITEM, POP_FAILURE_ITEM): new macros.
          Use them instead of copying the stack manipulating a zillion
          times.

        * regex.c (PUSH_FAILURE_POINT, pop_failure_point) [DEBUG]: save
          and restore a unique identification value for each failure point.

        * regexinc.c (partial_compiled_pattern_printer): don't print an
          extra / after duplicate commands.

        * regex.c (regex_compile): in back-reference case, allow a back
          reference to register `regnum'.  Otherwise, even `\(\)\1'
          fails, since regnum is 1 at the back-reference.

        * regex.c (re_match_2): in fail, don't examine the pattern if we
          restored to pend.

        * test_private.h: rename to private_tst.h.  Change includes.

        * regex.c (extend_bits_list): compute existing size for realloc
          in bytes, not blocks.

        * regex.c (re_match_2): in jump_past_next_alt, the for loop was
          missing its (empty) statement.  Even so, some register tests
          still fail, although in a different way than in the previous change.

Fri Dec 13 15:55:08 1991  Karl Berry  (karl at hayley)

        * regex.c (re_match_2): in jump_past_next_alt, unconditionally
          goto no_pop, since we weren't properly detecting if the
          alternative matched something anyway.  No, we need to not jump
          to keep the register values correct; just change to not look at
          register zero and not test RE_NO_EMPTY_ALTS (which is a
          compile-time thing).

        * regex.c (SET_REGS_MATCHED): start the loop at 1, since we never
          care about register zero until the very end.  (I think.)

        * regex.c (PUSH_FAILURE_POINT, pop_failure_point): go back to
          pushing and popping the active registers, instead of only doing
          the registers before a group: (fooq|fo|o)*qbar against fooqbar
          fails, since we restore back into the middle of group 1, yet it
          isn't active, because the previous restore clobbered the active flag.

Thu Dec 12 17:25:36 1991  Karl Berry  (karl at hayley)

        * regex.c (PUSH_FAILURE_POINT): do not call
          `equivalent_failure_points' after all; it causes the registers
          to be ``wrong'' (according to POSIX), and an infinite loop on
          `((a*)*)*' against `ab'.

        * regex.c (re_compile_fastmap): don't push `pend' on the failure
          stack.

Tue Dec 10 10:30:03 1991  Karl Berry  (karl at hayley)

        * regex.c (PUSH_FAILURE_POINT): if pushing same failure point that
          is on the top of the stack, fail.
        (equivalent_failure_points): new routine.

        * regex.c (re_match_2): add debug statements for every opcode we
          execute.

        * regex.c (regex_compile/handle_close): restore
          `fixup_inner_group_count' and `regnum' from the stack.

Mon Dec  9 13:51:15 1991  Karl Berry  (karl at hayley)

        * regex.c (PUSH_FAILURE_POINT): declare `this_reg' as int, so
          unsigned arithmetic doesn't happen when we don't want to save
          the registers.

Tue Dec  3 08:11:10 1991  Karl Berry  (karl at hayley)

        * regex.c (extend_bits_list): divide size by bits/block.

        * regex.c (init_bits_list): remove redundant assignmen to
          `bits_list_ptr'.

        * regexinc.c (partial_compiled_pattern_printer): don't do *p++
          twice in the same expr.

        * regex.c (re_match_2): at on_failure_jump, use the correct
          pattern positions for getting the stuff following the start_memory.

        * regex.c (struct register_info): remove the bits_list for the
          inner groups; make that a separate variable.

Mon Dec  2 10:42:07 1991  Karl Berry  (karl at hayley)

        * regex.c (PUSH_FAILURE_POINT): don't pass `failure_stack' as an
          arg; change callers.

        * regex.c (PUSH_FAILURE_POINT): print items in order they are
          pushed.
        (pop_failure_point): likewise.

        * regex.c (main): prompt for the pattern and string.

        * regex.c (FREE_VARIABLES) [!REGEX_MALLOC]: declare as nothing;
          remove #ifdefs from around calls.

        * regex.c (extract_number, extract_number_and_incr): declare static.

        * regex.c: remove the canned main program.
        * main.c: new file.
        * Makefile (COMMON): add main.o.

Tue Sep 24 06:26:51 1991  Kathy Hargreaves  (kathy at fosse)

        * regex.c (re_match_2): Made `pend' and `dend' not register variables.
          Only set string2 to string1 if string1 isn't null.
          Send address of p, d, regstart, regend, and reg_info to
          pop_failure_point.
          Put in more debug statements.

        * regex.c [debug]: Added global variable.
          (DEBUG_*PRINT*): Only print if `debug' is true.
          (DEBUG_DOUBLE_STRING_PRINTER): Changed DEBUG_STRING_PRINTER's
          name to this.
          Changed some comments.
          (PUSH_FAILURE_POINT): Moved and added some debugging statements.
          Was saving regstart on the stack twice instead of saving both
          regstart and regend; remedied this.
          [NUM_REGS_ITEMS]: Changed from 3 to 4, as now save lowest and
          highest active registers instead of highest used one.
          [NUM_NON_REG_ITEMS]: Changed name of NUM_OTHER_ITEMS to this.
          (NUM_FAILURE_ITEMS): Use active registers instead of number 0
          through highest used one.
          (re_match_2): Have pop_failure_point put things in the variables.
          (pop_failure_point): Have it do what the fail case in re_match_2
          did with the failure stack, instead of throwing away the stuff
          popped off.  re_match_2 can ignore results when it doesn't
          need them.


Thu Sep  5 13:23:28 1991  Kathy Hargreaves  (kathy at fosse)

        * regex.c (banner): Changed copyright years to be separate.

        * regex.c [CHAR_UNSIGNED]: Put __ at both ends of this name.
          [DEBUG, debug_count, *debug_p, DEBUG_PRINT_1, DEBUG_PRINT_2,
           DEBUG_COMPILED_PATTERN_PRINTER ,DEBUG_STRING_PRINTER]:
           defined these for debugging.
          (extract_number): Added this (debuggable) routine version of
          the macro EXTRACT_NUMBER.  Ditto for EXTRACT_NUMBER_AND_INCR.
          (re_compile_pattern): Set return_default_num_regs if the
          syntax bit RE_ALLOCATE_REGISTERS is set.
          [REGEX_MALLOC]: Renamed USE_ALLOCA to this.
          (BUF_POP): Got rid of this, as don't ever use it.
          (regex_compile): Made the type of `pattern' not be register.
          If DEBUG, print the pattern to compile.
          (re_match_2): If had a `$' in the pattern before a `^' then
          don't record the `^' as an anchor.
          Put (enum regexpcode) before references to b, as suggested
          [RE_NO_BK_BRACES]: Changed RE_NO_BK_CURLY_BRACES to this.
          (remove_pattern_offset): Removed this unused routine.
          (PUSH_FAILURE_POINT): Changed to only save active registers.
          Put in debugging statements.
          (re_compile_fastmap): Made `pattern' not a register variable.
          Use routine for extracting numbers instead of macro.
          (re_match_2): Made `p', `mcnt' and `mcnt2' not register variables.
          Added `num_regs_pushed' for debugging.
          Only malloc registers if the syntax bit RE_ALLOCATE_REGISTERS is set.
          Put in debug statements.
          Put the macro NOTE_INNER_GROUP's code inline, as it was the
          only called in one place.
          For debugging, extract numbers using routines instead of macros.
          In case fail: only restore pushed active registers, and added
          debugging statements.
          (pop_failure_point): Test for underfull stack.
          (group_can_match_nothing, common_op_can_match_nothing): For
          debugging, extract numbers using routines instead of macros.
          (regexec): Changed formal parameters to not be prototypes.
          Don't initialize `regs' or `private_preg' in their declarations.

Tue Jul 23 18:38:36 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h [RE_CONTEX_INDEP_OPS]: Moved the anchor stuff out of
          this bit.
          [RE_UNMATCHED_RIGHT_PAREN_ORD]: Defined this bit.
          [RE_CONTEXT_INVALID_ANCHORS]: Defined this bit.
          [RE_CONTEXT_INDEP_ANCHORS]: Defined this bit.
          Added RE_CONTEXT_INDEP_ANCHORS to all syntaxes which had
          RE_CONTEXT_INDEP_OPS.
          Took RE_ANCHORS_ONLY_AT_ENDS out of the POSIX basic syntax.
          Added RE_UNMATCHED_RIGHT_PAREN_ORD to the POSIX extended
          syntax.
          Took RE_REPEATED_ANCHORS_AWAY out of the POSIX extended syntax.
          Defined REG_NOERROR (which will probably have to go away again).
          Changed the type `off_t' to `regoff_t'.

        * regex.c: Changed some commments.
          (regex_compile): Added variable `had_an_endline' to keep track
          of if hit a `$' since the beginning of the pattern or the last
          alternative (if any).
          Changed RE_CONTEXT_INVALID_OPS and RE_CONTEXT_INDEP_OPS to
          RE_CONTEXT_INVALID_ANCHORS and RE_CONTEXT_INDEP_ANCHORS where
          appropriate.
          Put a `no_op' in the pattern if a repeat is only zero or one
          times; in this case and if it is many times (whereupon a jump
          backwards is pushed instead), keep track of the operator for
          verify_and_adjust_endlines.
          If RE_UNMATCHED_RIGHT_PAREN is set, make an unmatched
          close-group operator match `)'.
          Changed all error exits to exit (1).
          (remove_pattern_offset): Added this routine, but don't use it.
          (verify_and_adjust_endlines): At top of routine, if initialize
          routines run out of memory, return true after setting
          enough_memory false.
          At end of endline, et al. case, don't set *p to no_op.
          Repetition operators also set the level and active groups'
          match statuses, unless RE_REPEATED_ANCHORS_AWAY is set.
          (get_group_match_status): Put a return in front of call to get_bit.
          (re_compile_fastmap): Changed is_a_succeed_n to a boolean.
          If at end of pattern, then if the failure stack isn't empty,
          go back to the failure point.
          In *jump* case, only pop the stack if what's on top of it is
          where we've just jumped to.
          (re_search_2): Return -2 instead of val if val is -2.
          (group_can_match_nothing, alternative_can_match_nothing,
          common_op_can-match_nothing): Now pass in reg_info for the
          `duplicate' case.
          (re_match_2): Don't skip over the next alternative also if
          empty alternatives aren't allowed.
          In fail case, if failed to a backwards jump that's part of a
          repetition loop, pop the current failure point and use the
          next one.
          (pop_failure_point): Check that there's as many register items
          on the failure stack as the stack says there are.
          (common_op_can_match_nothing): Added variables `ret' and
          `reg_no' so can set reg_info for the group encountered.
          Also break without doing anything if hit a no_op or the other
          kinds of `endline's.
          If not done already, set reg_info in start_memory case.
          Put in no_pop_jump for an optimized succeed_n of zero repetitions.
          In succeed_n case, if the number isn't zero, then return false.
          Added `duplicate' case.

Sat Jul 13 11:27:38 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (REG_NOERROR): Added this error code definition.

        * regex.c: Took some redundant parens out of macros.
          (enum regexpcode): Added jump_past_next_alt.
          Wrapped some macros in `do..while (0)'.
          Changed some comments.
          (regex_compile): Use `fixup_alt_jump' instead of `fixup_jump'.
          Use `maybe_pop_jump' instead of `maybe_pop_failure_jump'.
          Use `jump_past_next_alt' instead of `no_pop_jump' when at the
          end of an alternative.
          (re_match_2): Used REGEX_ALLOCATE for the registers stuff.
          In stop_memory case: Add more boolean tests to see if the
          group is in a loop.
          Added jump_past_next_alt case, which doesn't jump over the
          next alternative if the last one didn't match anything.
          Unfortunately, to make this work with, e.g., `(a+?*|b)*'
          against `bb', I also had to pop the alternative's failure
          point, which in turn broke backtracking!
          In fail case: Detect a dummy failure point by looking at
          failure_stack.avail - 2, not stack[-2].
          (pop_failure_point): Only pop if the stack isn't empty; don't
          give an error if it is.  (Not sure yet this is correct.)
          (group_can_match_nothing): Make it return a boolean instead of int.
          Make it take an argument indicating the end of where it should look.
          If find a group that can match nothing, set the pointer
          argument to past the group in the pattern.
          Took out cases which can share with alternative_can_match_nothing
          and call common_op_can_match_nothing.
          Took ++ out of switch, so could call common_op_can_match_nothing.
          Wrote lots more for on_failure_jump case to handle alternatives.
          Main loop now doesn't look for matching stop_memory, but
          rather the argument END; return true if hit the matching
          stop_memory; this way can call itself for inner groups.
          (alternative_can_match_nothing): Added for alternatives.
          (common_op_can_match_nothing):  Added for previous two routines'
          common operators.
          (regerror): Returns a message saying there's no error if gets
          sent REG_NOERROR.

Wed Jul  3 10:43:15 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.c: Removed unnecessary enclosing parens from several macros.
          Put `do..while (0)' around a few.
          Corrected some comments.
          (INIT_FAILURE_STACK_SIZE): Deleted in favor of using
          INIT_FAILURE_ALLOC.
          (INIT_FAILURE_STACK, DOUBLE_FAILURE_STACK, PUSH_PATTERN_OP,
          PUSH_FAILURE_POINT): Made routines of the same name (but with all
          lowercase letters) into these macros, so could use `alloca'
          when USE_ALLOCA is defined.  The reason is stated below for
          bits lists.  Deleted analogous routines.
          (re_compile_fastmap): Added variable void *destination for
          PUSH_PATTERN_OP.
          (re_match_2): Added variable void *destination for REGEX_REALLOCATE.
          Used the failure stack macros in place of the routines.
          Detected a dummy failure point by inspecting the failure stack's
          (avail - 2)th element, not failure_stack.stack[-2].  This bug
          arose when used the failure stack macros instead of the routines.

        * regex.c [USE_ALLOCA]: Put this conditional around previous
          alloca stuff and defined these to work differently depending
          on whether or not USE_ALLOCA is defined:
          (REGEX_ALLOCATE): Uses either `alloca' or `malloc'.
          (REGEX_REALLOCATE): Uses either `alloca' or `realloc'.
          (INIT_BITS_LIST, EXTEND_BITS_LIST, SET_BIT_TO_VALUE): Defined
          macro versions of routines with the same name (only with all
          lowercase letters) so could use `alloc' in re_match_2.  This
          is to prevent core leaks when C-g is used in Emacs and to make
          things faster and avoid storage fragmentation.  These things
          have to be macros because the results of `alloca' go away with
          the routine by which it's called.
          (BITS_BLOCK_SIZE, BITS_BLOCK, BITS_MASK): Moved to above the
          above-mentioned macros instead of before the routines defined
          below regex_compile.
          (set_bit_to_value): Compacted some code.
          (reg_info_type): Changed inner_groups field to be bits_list_type
          so could be arbitrarily long and thus handle arbitrary nesting.
          (NOTE_INNER_GROUP): Put `do...while (0)' around it so could
          use as a statement.
          Changed code to use bits lists.
          Added variable void *destination for REGEX_REALLOCATE (whose call
          is several levels in).
          Changed variable name of `this_bit' to `this_reg'.
          (FREE_VARIABLES): Only define and use if USE_ALLOCA is defined.
          (re_match_2): Use REGEX_ALLOCATE instead of malloc.
          Instead of setting INNER_GROUPS of reg_info to zero, have to
          use INIT_BITS_LIST and return -2 (and free variables if
          USE_ALLOCA isn't defined) if it fails.

Fri Jun 28 13:45:07 1991  Karl Berry  (karl at hayley)

        * regex.c (re_match_2): set value of `dend' when we restore `d'.

        * regex.c: remove declaration of alloca.

        * regex.c (MISSING_ISGRAPH): rename to `ISGRAPH_MISSING'.

        * regex.h [_POSIX_SOURCE]: remove these conditionals; always
          define POSIX stuff.
        * regex.c (_POSIX_SOURCE): change conditionals to use `POSIX'
          instead.

Sat Jun  1 16:56:50 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.*: Changed RE_CONTEXTUAL_* to RE_CONTEXT_*,
          RE_TIGHT_VBAR to RE_TIGHT_ALT, RE_NEWLINE_OR to
          RE_NEWLINE_ALT, and RE_DOT_MATCHES_NEWLINE to RE_DOT_NEWLINE.

Wed May 29 09:24:11 1991  Karl Berry  (karl at hayley)

        * regex.texinfo (POSIX Pattern Buffers): cross-reference the
          correct node name (Match-beginning-of-line, not ..._line).
          (Syntax Bits): put @code around all syntax bits.

Sat May 18 16:29:58 1991  Karl Berry  (karl at hayley)

        * regex.c (global): add casts to keep broken compilers from
          complaining about malloc and realloc calls.

        * regex.c (isgraph) [MISSING_ISGRAPH]: change test to this,
          instead of `#ifndef isgraph', since broken compilers can't
          have both a macro and a symbol by the same name.

        * regex.c (re_comp, re_exec) [_POSIX_SOURCE]: do not define.
        (regcomp, regfree, regexec, regerror) [_POSIX_SOURCE && !emacs]:
         only define in this case.

Mon May  6 17:37:04 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (re_search, re_search_2): Changed BUFFER to not be const.

        * regex.c (re_compile_pattern): `^' is in a leading position if
          it precedes a newline.
          (various routines): Added or changed header comments.
          (double_pattern_offsets_list): Changed name from
          `extend_pattern_offsets_list'.
          (adjust_pattern_offsets_list): Changed return value from
          unsigned to void.
          (verify_and_adjust_endlines): Now returns `true' and `false'
          instead of 1 and 0.
          `$' is in a leading position if it follows a newline.
          (set_bit_to_value, get_bit_value): Exit with error if POSITION < 0
          so now calling routines don't have to.
          (init_failure_stack, inspect_failure_stack_top,
          pop_failure_stack_top, push_pattern_op, double_failure_stack):
          Now return value unsigned instead of boolean.
          (re_search, re_search_2): Changed BUFP to not be const.
          (re_search_2): Added variable const `private_bufp' to send to
          re_match_2.
          (push_failure_point): Made return value unsigned instead of boolean.

Sat May  4 15:32:22 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (re_compile_fastmap): Added extern for this.
          Changed some comments.

        * regex.c (re_compile_pattern): In case handle_bar: put invalid
          pattern test before levels matching stuff.
          Changed some commments.
          Added optimizing test for detecting an empty alternative that
          ends with a trailing '$' at the end of the pattern.
          (re_compile_fastmap): Moved failure_stack stuff to before this
          so could use it.  Made its stack dynamic.
          Made it return an int so that it could return -2 if its stack
          couldn't be allocated.
          Added to header comment (about the return values).
          (init_failure_stack): Wrote so both re_match_2 and
          re_compile_fastmap could use it similar stacks.
          (double_failure_stack): Added for above reasons.
          (push_pattern_op): Wrote for re_compile_fastmap.
          (re_search_2): Now return -2 if re_compile_fastmap does.
          (re_match_2): Made regstart and regend type failure_stack_element*.
          (push_failure_point): Made pattern_place and string_place type
          failure_stack_element*.
          Call double_failure_stack now.
          Return true instead of 1.

Wed May  1 12:57:21 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.c (remove_intervening_anchors): Avoid erroneously making
          ops into no_op's by making them no_op only when they're beglines.
          (verify_and_adjust_endlines): Don't make '$' a normal character
          if it's before a newline.
          Look for the endline op in *p, not p[1].
          (failure_stack_element): Added this declaration.
          (failure_stack_type): Added this declaration.
          (INIT_FAILURE_STACK_SIZE, FAILURE_STACK_EMPTY,
          FAILURE_STACK_PTR_EMPTY, REMAINING_AVAIL_SLOTS): Added for
          failure stack.
          (FAILURE_ITEM_SIZE, PUSH_FAILURE_POINT): Deleted.
          (FREE_VARIABLES): Now free failure_stack.stack instead of stackb.
          (re_match_2): deleted variables `initial_stack', `stackb',
          `stackp', and `stacke' and added `failure_stack' to replace them.
          Replaced calls to PUSH_FAILURE_POINT with those to
          push_failure_point.
          (push_failure_point): Added for re_match_2.
          (pop_failure_point): Rewrote to use a failure_stack_type of stack.
          (can_match_nothing): Moved definition to below re_match_2.
          (bcmp_translate): Moved definition to below re_match_2.

Mon Apr 29 14:20:54 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.c (enum regexpcode): Added codes endline_before_newline
          and repeated_endline_before_newline so could detect these
          types of endlines in the intermediate stages of a compiled
          pattern.
          (INIT_FAILURE_ALLOC): Renamed NFAILURES to this and set it to 5.
          (BUF_PUSH): Put `do {...} while 0' around this.
          (BUF_PUSH_2): Defined this to cut down on expansion of EXTEND_BUFFER.
          (regex_compile): Changed some comments.
          Now push endline_before_newline if find a `$' before a newline
          in the pattern.
          If a `$' might turn into an ordinary character, set laststart
          to point to it.
          In '^' case, if syntax bit RE_TIGHT_VBAR is set, then for `^'
          to be in a leading position, it must be first in the pattern.
          Don't have to check in one of the else clauses that it's not set.
          If RE_CONTEXTUAL_INDEP_OPS isn't set but RE_ANCHORS_ONLY_AT_ENDS
          is, make '^' a normal character if it isn't first in the pattern.
          Can only detect at the end if a '$' after an alternation op is a
          trailing one, so can't immediately detect empty alternatives
          if a '$' follows a vbar.
          Added a picture of the ``success jumps'' in alternatives.
          Have to set bufp->used before calling verify_and_adjust_endlines.
          Also do it before returning all error strings.
          (remove_intervening_anchors): Now replaces the anchor with
          repeated_endline_before_newline if it's an endline_before_newline.
          (verify_and_adjust_endlines): Deleted SYNTAX parameter (could
          use bufp's) and added GROUP_FORWARD_MATCH_STATUS so could
          detect back references referring to empty groups.
          Added variable `bend' to point past the end of the pattern buffer.
          Added variable `previous_p' so wouldn't have to reinspect the
          pattern buffer to see what op we just looked at.
          Added endline_before_newline and repeated_endline_before_newline
          cases.
          When checking if in a trailing position, added case where '$'
          has to be at the pattern's end if either of the syntax bits
          RE_ANCHORS_ONLY_AT_ENDS or RE_TIGHT_VBAR are set.
          Since `endline' can have the intermediate form `endline_in_repeat',
          have to change it to `endline' if RE_REPEATED_ANCHORS_AWAY
          isn't set.
          Now disallow empty alternatives with trailing endlines in them
          if RE_NO_EMPTY_ALTS is set.
          Now don't make '$' an ordinary character if it precedes a newline.
          Don't make it an ordinary character if it's before a newline.
          Back references now affect the level matching something only if
          they refer to nonempty groups.
          (can_match_nothing): Now increment p1 in the switch, which
          changes many of the cases, but makes the code more like what
          it was derived from.
          Adjust the return statement to reflect above.
          (struct register_info): Made `can_match_nothing' field an int
          instead of a bit so could have -1 in it if never set.
          (MAX_FAILURE_ITEMS): Changed name from MAX_NUM_FAILURE_ITEMS.
          (FAILURE_ITEM_SIZE): Defined how much space a failure items uses.
          (PUSH_FAILURE_POINT): Changed variable `last_used_reg's name
          to `highest_used_reg'.
          Added variable `num_stack_items' and changed `len's name to
          `stack_length'.
          Test failure stack limit in terms of number of items in it, not
          in terms of its length.  rms' fix tested length against number
          of items, which was a misunderstanding.
          Use `realloc' instead of `alloca' to extend the failure stack.
          Use shifts instead of multiplying by 2.
          (FREE_VARIABLES): Free `stackb' instead of `initial_stack', as
          might may have been reallocated.
          (re_match_2): When mallocing `initial_stack', now multiply
          the number of items wanted (what was there before) by
          FAILURE_ITEM_SIZE.
          (pop_failure_point): Need this procedure form of the macro of
          the same name for debugging, so left it in and deleted the
          macro.
          (recomp): Don't free the pattern buffer's translate field.

Mon Apr 15 09:47:47 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_DUP_MAX): Moved to outside of #ifdef _POSIX_SOURCE.
        * regex.c (#include <sys/types.h>): Removed #ifdef _POSIX_SOURCE
          condition.
          (malloc, realloc): Made return type void* #ifdef __STDC__.
          (enum regexpcode): Added endline_in_repeat for the compiler's
          use; this never ends up on the final compiled pattern.
          (INIT_PATTERN_OFFSETS_LIST_SIZE): Initial size for
          pattern_offsets_list_type.
          (pattern_offset_type): Type for pattern offsets.
          (pattern_offsets_list_type): Type for keeping a list of
          pattern offsets.
          (anchor_list_type): Changed to above type.
          (PATTERN_OFFSETS_LIST_PTR_FULL): Tests if a pattern offsets
          list is full.
          (ANCHOR_LIST_PTR_FULL): Changed to above.
          (BIT_BLOCK_SIZE): Changed to BITS_BLOCK_SIZE and moved to
          above bits list routines below regex_compile.
          (op_list_type): Defined to be pattern_offsets_list_type.
          (compile_stack_type): Changed offsets to be
          pattern_offset_type instead of unsigned.
          (pointer): Changed the name of all structure fields from this
          to `avail'.
          (COMPILE_STACK_FULL): Changed so the stack is full if `avail'
          is equal to `size' instead of `size' - 1.
          (GET_BUFFER_SPACE): Changed `>=' to `>' in the while statement.
          (regex_compile): Added variable `enough_memory' so could check
          that routine that verifies '$' positions could return an
          allocation error.
          (group_count): Deleted this variable, as `regnum' already does
          this work.
          (op_list): Added this variable to keep track of operations
          needed for verifying '$' positions.
          (anchor_list): Now initialize using routine
          `init_pattern_offsets_list'.
          Consolidated the three bits_list initializations.
          In case '$': Instead of trying to go past constructs which can
          follow '$', merely detect the special case where it has to be
          at the pattern's end, fix up any fixup jumps if necessary,
          record the anchor if necessary and add an `endline' (and
          possibly two `no-op's) to the pattern; will call a routine at
          the end to verify if it's in a valid position or not.
          (init_pattern_offsets_list): Added to initialize pattern
          offsets lists.
          (extend_anchor_list): Renamed this extend_pattern_offsets_list
          and renamed parameters and internal variables appropriately.
          (add_pattern_offset): Added this routine which both
          record_anchor_position and add_op call.
          (adjust_pattern_offsets_list): Add this routine to adjust by
          some increment all the pattern offsets a list of such after a
          given position.
          (record_anchor_position): Now send in offset instead of
          calculating it and just call add_pattern_offset.
          (adjust_anchor_list): Replaced by above routine.
          (remove_intervening_anchors): If the anchor is an `endline'
          then replace it with `endline_in_repeat' instead of `no_op'.
          (add_op):  Added this routine to call in regex_compile
          wherever push something relevant to verifying '$' positions.
          (verify_and_adjust_endlines): Added routine to (1) verify that
          '$'s in a pattern buffer (represented by `endline') were in
          valid positions and (2) whether or not they were anchors.
          (BITS_BLOCK_SIZE): Renamed BIT_BLOCK_SIZE and moved to right
          above bits list routines.
          (BITS_BLOCK): Defines which array element of a bits list the
          bit corresponding to a given position is in.
          (BITS_MASK): Has a 1 where the bit (in a bit list array element)
          for a given position is.

Mon Apr  1 12:09:06 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.c (BIT_BLOCK_SIZE): Defined this for using with
          bits_list_type, abstracted from level_list_type so could use
          for more things than just the level match status.
          (regex_compile): Renamed `level_list' variable to
          `level_match_status'.
          Added variable `group_match_status' of type bits_list_type.
          Kept track of whether or not for all groups any of them
          matched other than the empty string, so detect if a back
          reference in front of a '^' made it nonleading or not.
          Do this by setting a match status bit for all active groups
          whenever leave a group that matches other than the empty string.
          Could detect which groups are active by going through the
          stack each time, but or-ing a bits list of active groups with
          a bits list of group match status is faster, so make a bits
          list of active groups instead.
          Have to check that '^' isn't in a leading position before
          going to normal_char.
          Whenever set level match status of the current level, also set
          the match status of all active groups.
          Increase the group count and make that group active whenever
          open a group.
          When close a group, only set the next level down if the
          current level matches other than the empty string, and make
          the current group inactive.
          At a back reference, only set a level's match status if the
          group to which the back reference refers matches other than
          the empty string.
          (init_bits_list): Added to initialize a bits list.
          (get_level_value): Deleted this.  (Made into
          get_level_match_status.)
          (extend_bits_list): Added to extend a bits list.  (Made this
          from deleted routine `extend_level_list'.)
          (get_bit): Added to get a bit value from a bits list.  (Made
          this from deleted routine `get_level_value'.)
          (set_bit_to_value): Added to set a bit in a bits list.  (Made
          this from deleted routine `set_level_value'.)
          (get_level_match_status): Added this to get the match status
          of a given level.  (Made from get_level_value.)
          (set_this_level, set_next_lower_level): Made all routines
          which set bits extend the bits list if necessary, thus they
          now return an unsigned value to indicate whether or not the
          reallocation failed.
          (increase_level): No longer extends the level list.
          (make_group_active): Added to mark as active a given group in
          an active groups list.
          (make_group_inactive): Added to mark as inactive a given group
          in an active groups list.
          (set_match_status_of_active_groups): Added to set the match
          status of all currently active groups.
          (get_group_match_status): Added to get a given group's match status.
          (no_levels_match_anything): Removed the paramenter LEVEL.
          (PUSH_FAILURE_POINT): Added rms' bug fix and changed RE_NREGS
          to num_internal_regs.

Sun Mar 31 09:04:30 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_ANCHORS_ONLY_AT_ENDS): Added syntax so could
          constrain '^' and '$' to only be anchors if at the beginning
          and end of the pattern.
          (RE_SYNTAX_POSIX_BASIC): Added the above bit.

        * regex.c (enum regexcode): Changed `unused' to `no_op'.
          (this_and_lower_levels_match_nothing): Deleted forward reference.
          (regex_compile): case '^': if the syntax bit RE_ANCHORS_ONLY_AT_ENDS
          is set, then '^' is only an anchor if at the beginning of the
          pattern; only record anchor position if the syntax bit
          RE_REPEATED_ANCHORS_AWAY is set; the '^' is a normal char if
          the syntax bit RE_ANCHORS_ONLY_AT_END is set and we're not at
          the beginning of the pattern (and neither RE_CONTEXTUAL_INDEP_OPS
          nor RE_CONTEXTUAL_INDEP_OPS syntax bits are set).
          Only adjust the anchor list if the syntax bit
          RE_REPEATED_ANCHORS_AWAY is set.

        * regex.c (level_list_type): Use to detect when '^' is
          in a leading position.
          (regex_compile): Added level_list_type level_list variable in
          which we keep track of whether or not a grouping level (in its
          current or most recent incarnation) matches anything besides the
          empty string.  Set the bit for the i-th level when detect it
          should match something other than the empty string and the bit
          for the (i-1)-th level when leave the i-th group.  Clear all
          bits for the i-th and higher levels if none of 0--(i - 1)-th's
          bits are set when encounter an alternation operator on that
          level.  If no levels are set when hit a '^', then it is in a
          leading position.  We keep track of which level we're at by
          increasing a variable current_level whenever we encounter an
          open-group operator and decreasing it whenever we encounter a
          close-group operator.
          Have to adjust the anchor list contents whenever insert
          something ahead of them (such as on_failure_jump's) in the
          pattern.
          (adjust_anchor_list): Adjusts the offsets in an anchor list by
          a given increment starting at a given start position.
          (get_level_value): Returns the bit setting of a given level.
          (set_level_value): Sets the bit of a given level to a given value.
          (set_this_level): Sets (to 1) the bit of a given level.
          (set_next_lower_level): Sets (to 1) the bit of (LEVEL - 1) for a
          given LEVEL.
          (clear_this_and_higher_levels): Clears the bits for a given
          level and any higher levels.
          (extend_level_list): Adds sizeof(unsigned) more bits to a level list.
          (increase_level): Increases by 1 the value of a given level variable.
          (decrease_level): Decreases by 1 the value of a given level variable.
          (lower_levels_match_nothing): Checks if any levels lower than
          the given one match anything.
          (no_levels_match_anything): Checks if any levels match anything.
          (re_match_2): At case wordbeg: before looking at d-1, check that
          we're not at the string's beginning.
          At case wordend: Added some illuminating parentheses.

Mon Mar 25 13:58:51 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NO_ANCHOR_AT_NEWLINE): Changed syntax bit name
          from RE_ANCHOR_NOT_NEWLINE because an anchor never matches the
          newline itself, just the empty string either before or after it.
          (RE_REPEATED_ANCHORS_AWAY): Added this syntax bit for ignoring
          anchors inside groups which are operated on by repetition
          operators.
          (RE_DOT_MATCHES_NEWLINE): Added this bit so the match-any-character
          operator could match a newline when it's set.
          (RE_SYNTAX_POSIX_BASIC): Set RE_DOT_MATCHES_NEWLINE in this.
          (RE_SYNTAX_POSIX_EXTENDED): Set RE_DOT_MATCHES_NEWLINE and
          RE_REPEATED_ANCHORS_AWAY in this.
          (regerror): Changed prototypes to new POSIX spec.

        * regex.c (anchor_list_type): Added so could null out anchors inside
          repeated groups.
          (ANCHOR_LIST_PTR_FULL): Added for above type.
          (compile_stack_element): Changed name from stack_element.
          (compile_stack_type): Changed name from compile_stack.
          (INIT_COMPILE_STACK_SIZE): Changed name from INIT_STACK_SIZE.
          (COMPILE_STACK_EMPTY): Changed name from STACK_EMPTY.
          (COMPILE_STACK_FULL): Changed name from STACK_FULL.
          (regex_compile): Changed SYNTAX parameter to non-const.
          Changed variable name `stack' to `compile_stack'.
          If syntax bit RE_REPEATED_ANCHORS_AWAY is set, then naively put
          anchors in a list when encounter them and then set them to
          `unused' when detect they are within a group operated on by a
          repetition operator.  Need something more sophisticated than
          this, as they should only get set to `unused' if they are in
          positions where they would be anchors.  Also need a better way to
          detect contextually invalid anchors.
          Changed some commments.
          (is_in_compile_stack): Changed name from `is_in_stack'.
          (extend_anchor_list): Added to do anchor stuff.
          (record_anchor_position): Added to do anchor stuff.
          (remove_intervening_anchors): Added to do anchor stuff.
          (re_match_2): Now match a newline with the match-any-character
          operator if RE_DOT_MATCHES_NEWLINE is set.
          Compacted some code.
          (regcomp): Added new POSIX newline information to the header
          commment.
          If REG_NEWLINE cflag is set, then now unset RE_DOT_MATCHES_NEWLINE
          in syntax.
          (put_in_buffer): Added to do new POSIX regerror spec.  Called
          by regerror.
          (regerror): Changed to take a pattern buffer, error buffer and
          its size, and return type `size_t', the size of the full error
          message, and the first ERRBUF_SIZE - 1 characters of the full
          error message in the error buffer.

Wed Feb 27 16:38:33 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (#include <sys/types.h>): Removed this as new POSIX
          standard has the user include it.
          (RE_SYNTAX_POSIX_BASIC and RE_SYNTAX_POSIX_EXTENDED): Removed
          RE_HAT_LISTS_NOT_NEWLINE as new POSIX standard has the cflag
          REG_NEWLINE now set this.  Similarly, added syntax bit
          RE_ANCHOR_NOT_NEWLINE as this is now unset by REG_NEWLINE.
          (RE_SYNTAX_POSIX_BASIC): Removed syntax bit
          RE_NO_CONSECUTIVE_REPEATS as POSIX now allows them.

        * regex.c (#include <sys/types.h>): Added this as new POSIX
          standard has the user include it instead of us putting it in
          regex.h.
          (extern char *re_syntax_table): Made into an extern so the
          user could allocate it.
          (DO_RANGE): If don't find a range end, now goto invalid_range_end
          instead of unmatched_left_bracket.
          (regex_compile): Made variable SYNTAX non-const.????
          Reformatted some code.
          (re_compile_fastmap): Moved is_a_succeed_n's declaration to
          inner braces.
          Compacted some code.
          (SET_NEWLINE_FLAG): Removed and put inline.
          (regcomp): Made variable `syntax' non-const so can unset
          RE_ANCHOR_NOT_NEWLINE syntax bit if cflag RE_NEWLINE is set.
          If cflag RE_NEWLINE is set, set the RE_HAT_LISTS_NOT_NEWLINE
          syntax bit and unset RE_ANCHOR_NOT_NEWLINE one of `syntax'.

Wed Feb 20 16:33:38 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NO_CONSECUTIVE_REPEATS): Changed name from
          RE_NO_CONSEC_REPEATS.
          (REG_ENESTING): Deleted this POSIX return value, as the stack
          is now unbounded.
          (struct re_pattern_buffer): Changed some comments.
          (re_compile_pattern): Changed a comment.
          Deleted check on stack upper bound and corresponding error.
          Now when there's no interval contents and it's the end of the
          pattern, go to unmatched_left_curly_brace instead of end_of_pattern.
          Removed nesting_too_deep error, as the stack is now unbounded.
          (regcomp): Removed REG_ENESTING case, as the stack is now unbounded.
          (regerror): Removed REG_ENESTING case, as the stack is now unbounded.

        * regex.c (MAX_STACK_SIZE): Deleted because don't need upper
          bound on array indexed with an unsigned number.

Sun Feb 17 15:50:24 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h: Changed and added some comments.

        * regex.c (init_syntax_once): Made `_' a word character.
          (re_compile_pattern): Added a comment.
          (re_match_2): Redid header comment.
          (regexec): With header comment about PMATCH, corrected and
          removed details found regex.h, adding a reference.

Fri Feb 15 09:21:31 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.c (DO_RANGE): Removed argument parentheses.
          Now get untranslated range start and end characters and set
          list bits for the translated (if at all) versions of them and
          all characters between them.
          (re_match_2): Now use regs->num_regs instead of num_regs_wanted
          wherever possible.
          (regcomp): Now build case-fold translate table using isupper
          and tolower facilities so will work on foreign language characters.

Sat Feb  9 16:40:03 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_HAT_LISTS_NOT_NEWLINE): Changed syntax bit name
          from RE_LISTS_NOT_NEWLINE as it only affects nonmatching lists.
          Changed all references to the match-beginning-of-string
          operator to match-beginning-of-line operator, as this is what
          it does.
          (RE_NO_CONSEC_REPEATS): Added this syntax bit.
          (RE_SYNTAX_POSIX_BASIC): Added above bit to this.
          (REG_PREMATURE_END): Changed name to REG_EEND.
          (REG_EXCESS_NESTING): Changed name to REG_ENESTING.
          (REG_TOO_BIG): Changed name to REG_ESIZE.
          (REG_INVALID_PREV_RE): Deleted this return POSIX value.
          Added and changed some comments.

        * regex.c (re_compile_pattern): Now sets the pattern buffer's
          `return_default_num_regs' field.
          (typedef struct stack_element, stack_type, INIT_STACK_SIZE,
          MAX_STACK_SIZE, STACK_EMPTY, STACK_FULL): Added for regex_compile.
          (INIT_BUF_SIZE): Changed value from 28 to 32.
          (BUF_PUSH): Changed name from BUFPUSH.
          (MAX_BUF_SIZE): Added so could use in many places.
          (IS_CHAR_CLASS_STRING): Replaced is_char_class with this.
          (regex_compile): Added a stack which could grow dynamically
          and which has struct elements.
          Go back to initializing `zero_times_ok' and `many_time_ok' to
          0 and |=ing them inside the loop.
          Now disallow consecutive repetition operators if the syntax
          bit RE_NO_CONSEC_REPEATS is set.
          Now detect trailing backslash when the compiler is expecting a
          `?' or a `+'.
          Changed calls to GET_BUFFER_SPACE which asked for 6 to ask for
          3, as that's all they needed.
          Now check for trailing backslash inside lists.
          Now disallow an empty alternative right before an end-of-line
          operator.
          Now get buffer space before leaving space for a fixup jump.
          Now check if at pattern end when at open-interval operator.
          Added some comments.
          Now check if non-interval repetition operators follow an
          interval one if the syntax bit RE_NO_CONSEC_REPEATS is set.
          Now only check if what precedes an interval repetition
          operator isn't a regular expression which matches one
          character if the syntax bit RE_NO_CONSEC_REPEATS is set.
          Now return "Unmatched [ or [^" instead of "Unmatched [".
          (is_in_stack): Added to check if a given register number is in
          the stack.
          (re_match_2): If initial variable allocations fail, return -2,
          instead of -1.
          Now set reg's `num_regs' field when allocating regs.
          Now before allocating them, free regs->start and end if they
          aren't NULL and return -2 if either allocation fails.
          Now use regs->num_regs instead of num_regs_wanted to control
          regs loops.
          Now increment past the newline when matching it with an
          end-of-line operator.
          (recomp): Added to the header comment.
          Now return REG_ESUBREG if regex_compile returns "Unmatched [
          or [^" instead of doing so if it returns "Unmatched [".
          Now return REG_BADRPT if in addition to returning "Missing
          preceding regular expression", regex_compile returns "Invalid
          preceding regular expression".
          Now return new return value names (see regex.h changes).
          (regexec): Added to header comment.
          Initialize regs structure.
          Now match whole string.
          Now always free regs.start and regs.end instead of just when
          the string matched.
          (regerror): Now return "Regex error: Unmatched [ or [^.\n"
          instead of "Regex error: Unmatched [.\n".
          Now return "Regex error: Preceding regular expression either
          missing or not simple.\n" instead of "Regex error: Missing
          preceding regular expression.\n".
          Removed REG_INVALID_PREV_RE case (it got subsumed into the
          REG_BADRPT case).

Thu Jan 17 09:52:35 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h: Changed a comment.

        * regex.c: Changed and added large header comments.
          (re_compile_pattern): Now if detect that `laststart' for an
          interval points to a byte code for a regular expression which
          matches more than one character, make it an internal error.
          (regerror): Return error message, don't print it.

Tue Jan 15 15:32:49 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (regcomp return codes): Added GNU ones.
          Updated some comments.

        * regex.c (DO_RANGE): Changed `obscure_syntax' to `syntax'.
          (regex_compile): Added `following_left_brace' to keep track of
          where pseudo interval following a valid interval starts.
          Changed some instances that returned "Invalid regular
          expression" to instead return error strings coinciding with
          POSIX error codes.
          Changed some comments.
          Now consider only things between `[:' and `:]' to be possible
          character class names.
          Now a character class expression can't end a pattern; at
          least a `]' must close the list.
          Now if the syntax bit RE_NO_BK_CURLY_BRACES is set, then a
          valid interval must be followed by yet another to get an error
          for preceding an interval (in this case, the second one) with
          a regular expression that matches more than one character.
          Now if what follows a valid interval begins with a open
          interval operator but doesn't begin a valid interval, then set
          following_left_bracket to it, put it in C and go to
          normal_char label.
          Added some comments.
          Return "Invalid character class name" instead of "Invalid
          character class".
          (regerror): Return messages for all POSIX error codes except
          REG_ECOLLATE and REG_NEWLINE, along with all GNU error codes.
          Added `break's after all cases.
          (main): Call re_set_syntax instead of setting `obscure_syntax'
          directly.

Sat Jan 12 13:37:59 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (Copyright): Updated date.
          (#include <sys/types.h>): Include unconditionally.
          (RE_CANNOT_MATCH_NEWLINE): Deleted this syntax bit.
          (RE_SYNTAX_POSIX_BASIC, RE_SYNTAX_POSIX_EXTENDED): Removed
          setting the RE_ANCHOR_NOT_NEWLINE syntax bit from these.
          Changed and added some comments.
          (struct re_pattern_buffer):  Changed some flags from chars to bits.
          Added field `syntax'; holds which syntax pattern was compiled with.
          Added bit flag `return_default_num_regs'.
          (externs for GNU and Berkeley UNIX routines): Added `const's to
          parameter types to be compatible with POSIX.
          (#define const): Added to support old C compilers.

        * regex.c (Copyright): Updated date.
          (enum regexpcode): Deleted `newline'.
          (regex_compile): Renamed re_compile_pattern to this, added a
          syntax parameter so it can set the pattern buffer's `syntax'
          field.
          Made `pattern', and `size' `const's so could pass to POSIX
          interface routines; also made `const' whatever interval
          variables had to be to make this work.
          Changed references to `obscure_syntax' to new parameter `syntax'.
          Deleted putting `newline' in buffer when see `\n'.
          Consider invalid character classes which have nothing wrong
          except the character class name; if so, return character-class error.
          (is_char_class): Added routine for regex_compile.
          (re_compile_pattern): added a new one which calls
          regex_compile with `obscure_syntax' as the actual parameter
          for the formal `syntax'.
          Gave this the old routine's header comments.
          Made `pattern', and `size' `const's so could use POSIX interface
          routine parameters.
          (re_search, re_search_2, re_match, re_match_2): Changed
          `pbufp' to `bufp'.
          (re_search_2, re_match_2): Changed `mstop' to `stop'.
          (re_search, re_search_2): Made all parameters except `regs'
          `const's so could use POSIX interface routines parameters.
          (re_search_2): Added private copies of `const' parameters so
          could change their values.
          (re_match_2): Made all parameters except `regs' `const's so
          could use POSIX interface routines parameters.
          Changed `size1' and `size2' parameters to `size1_arg' and
          `size2_arg' and so could change; added local `size1' and
          `size2' and set to these.
          Added some comments.
          Deleted `newline' case.
          `begline' can also possibly match if `d' contains a newline;
          if it does, we have to increment d to point past the newline.
          Replaced references to `obscure_syntax' with `bufp->syntax'.
          (re_comp, re_exec): Made parameter `s' a `const' so could use POSIX
          interface routines parameters.
          Now call regex_compile, passing `obscure_syntax' via the
          `syntax' parameter.
          (re_exec): Made local `len' a `const' so could pass to re_search.
          (regcomp): Added header comment.
          Added local `syntax' to set and pass to regex_compile rather
          than setting global `obscure_syntax' and passing it.
          Call regex_compile with its `syntax' parameter rather than
          re_compile_pattern.
          Return REG_ECTYPE if character-class error.
          (regexec): Don't initialize `regs' to anything.
          Made `private_preg' a nonpointer so could set to what the
          constant `preg' points.
          Initialize `private_preg's `return_default_num_regs' field to
          zero because want to return `nmatch' registers, not however
          many there are subexpressions in the pattern.
          Also test if `nmatch' > 0 to see if should pass re_match `regs'.

Tue Jan  8 15:57:17 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (struct re_pattern_buffer): Reworded comment.

        * regex.c (EXTEND_BUFFER): Also reset beg_interval.
          (re_search_2): Return val if val = -2.
          (NUM_REG_ITEMS): Listed items in comment.
          (NUM_OTHER_ITEMS): Defined this for using in > 1 definition.
          (MAX_NUM_FAILURE_ITEMS): Replaced `+ 2' with NUM_OTHER_ITEMS.
          (NUM_FAILURE_ITEMS): As with definition above and added to
          comment.
          (PUSH_FAILURE_POINT): Replaced `* 2's with `<< 1's.
          (re_match_2): Test with equality with 1 to see pbufp->bol and
          pbufp->eol are set.

Fri Jan  4 15:07:22 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (struct re_pattern_buffer): Reordered some fields.
          Updated some comments.
          Added not_bol and not_eol fields.
          (extern regcomp, regexec, regerror): Added return types.
          (extern regfree): Added `extern'.

        * regex.c (min): Deleted unused macro.
          (re_match_2): Compacted some code.
          Removed call to macro `min' from `for' loop.
          Fixed so unused registers get filled with -1's.
          Fail if the pattern buffer's `not_bol' field is set and
          encounter a `begline'.
          Fail if the pattern buffer's `not_eol' field is set and
          encounter a `endline'.
          Deleted redundant check for empty stack in fail case.
          Don't free pattern buffer's components in re_comp.
          (regexec): Initialize variable regs.
          Added `private_preg' pattern buffer so could set `not_bol' and
          `not_eol' fields and hand to re_match.
          Deleted naive attempt to detect anchors.
          Set private pattern buffer's `not_bol' and `not_eol' fields
          according to eflags value.
          `nmatch' must also be > 0 for us to bother allocating
          registers to send to re_match and filling pmatch
          with their results after the call to re_match.
          Send private pattern buffer instead of argument to re_match.
          If use the registers, always free them and then set them to NULL.
          (regerror): Added this Posix routine.
          (regfree): Added this Posix routine.

Tue Jan  1 15:02:45 1991  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NREGS): Deleted this definition, as now the user
          can choose how many registers to have.
          (REG_NOTBOL, REG_NOTEOL): Defined these Posix eflag bits.
          (REG_NOMATCH, REG_BADPAT, REG_ECOLLATE, REG_ECTYPE,
          REG_EESCAPE, REG_ESUBREG, REG_EBRACK, REG_EPAREN, REG_EBRACE,
          REG_BADBR, REG_ERANGE, REG_ESPACE, REG_BADRPT, REG_ENEWLINE):
          Defined these return values for Posix's regcomp and regexec.
          Updated some comments.
          (struct re_pattern_buffer): Now typedef this as regex_t
          instead of the other way around.
          (struct re_registers): Added num_regs field.  Made start and
          end fields pointers to char instead of fixed size arrays.
          (regmatch_t): Added this Posix register type.
          (regcomp, regexec, regerror, regfree): Added externs for these
          Posix routines.

        * regex.c (enum boolean): Typedefed this.
          (re_pattern_buffer): Reformatted some comments.
          (re_compile_pattern): Updated some comments.
          Always push start_memory and its attendant number whenever
          encounter a group, not just when its number is less than the
          previous maximum number of registers; same for stop_memory.
          Get 4 bytes of buffer space instead of 2 when pushing a
          set_number_at.
          (can_match_nothing): Added this to elaborate on and replace
          code in re_match_2.
          (reg_info_type): Made can_match_nothing field a bit instead of int.
          (MIN): Added for re_match_2.
          (re_match_2 macros): Changed all `for' loops which used
          RE_NREGS to now use num_internal_regs as upper bounds.
          (MAX_NUM_FAILURE_ITEMS): Use num_internal_regs instead of RE_NREGS.
          (POP_FAILURE_POINT): Added check for empty stack.
          (FREE_VARIABLES): Added this to free (and set to NULL)
          variables allocated in re_match_2.
          (re_match_2): Rearranged parameters to be in order.
          Added variables num_regs_wanted (how many registers the user wants)
          and num_internal_regs (how many groups there are).
          Allocated initial_stack, regstart, regend, old_regstart,
          old_regend, reginfo, best_regstart, and best_regend---all
          which used to be fixed size arrays.  Free them all and return
          -1 if any fail.
          Free above variables if starting position pos isn't valid.
          Changed all `for' loops which used RE_NREGS to now use
          num_internal_regs as upper bounds---except for the loops which
          fill regs; then use num_regs_wanted.
          Allocate regs if the user has passed it and wants more than 0
          registers filled.
          Set regs->start[i] and regs->end[i] to -1 if either
          regstart[i] or regend[i] equals -1, not just the first.
          Free allocated variables before returning.
          Updated some comments.
          (regcomp): Return REG_ESPACE, REG_BADPAT, REG_EPAREN when
          appropriate.
          Free translate array.
          (regexec): Added this Posix interface routine.

Mon Dec 24 14:21:13 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h: If _POSIX_SOURCE is defined then #include <sys/types.h>.
          Added syntax bit RE_CANNOT_MATCH_NEWLINE.
          Defined Posix cflags: REG_EXTENDED, REG_NEWLINE, REG_ICASE, and
            REG_NOSUB.
          Added fields re_nsub and no_sub to struct re_pattern_buffer.
          Typedefed regex_t to be `struct re_pattern_buffer'.

        * regex.c (CHAR_SET_SIZE): Defined this to be 256 and replaced
          incidences of this value with this constant.
          (re_compile_pattern): Added switch case for `\n' and put
          `newline' into the pattern buffer when encounter this.
          Increment the pattern_buffer's `re_nsub' field whenever open a
          group.
          (re_match_2): Match a newline with `newline'---provided the
          syntax bit RE_CANNOT_MATCH_NEWLINE isn't set.
          (regcomp): Added this Posix interface routine.
          (enum test_type): Added interface_test tag.
          (main): Added Posix interface test.

Tue Dec 18 12:58:12 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (struct re_pattern_buffer): reformatted so would fit
          in texinfo documentation.

Thu Nov 29 15:49:16 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NO_EMPTY_ALTS): Added this bit.
          (RE_SYNTAX_POSIX_EXTENDED): Added above bit.

        * regex.c (re_compile_pattern): Disallow empty alternatives only
          when RE_NO_EMPTY_ALTS is set, not when RE_CONTEXTUAL_INVALID_OPS is.
          Changed RE_NO_BK_CURLY_BRACES to RE_NO_BK_PARENS when testing
          for empty groups at label handle_open.
          At label handle_bar: disallow empty alternatives if RE_NO_EMPTY_ALTS
          is set.
          Rewrote some comments.

          (re_compile_fastmap): cleaned up code.

          (re_search_2): Rewrote comment.

          (struct register_info): Added field `inner_groups'; it records
          which groups are inside of the current one.
          Added field can_match_nothing; it's set if the current group
          can match nothing.
          Added field ever_match_something; it's set if current group
          ever matched something.

          (INNER_GROUPS): Added macro to access inner_groups field of
          struct register_info.

          (CAN_MATCH_NOTHING): Added macro to access can_match_nothing
          field of struct register_info.

          (EVER_MATCHED_SOMETHING): Added macro to access
          ever_matched_something field of struct register_info.

          (NOTE_INNER_GROUP): Defined macro to record that a given group
          is inside of all currently active groups.

          (re_match_2): Added variables *p1 and mcnt2 (multipurpose).
          Added old_regstart and old_regend arrays to hold previous
          register values if they need be restored.
          Initialize added fields and variables.
          case start_memory: Find out if the group can match nothing.
            Save previous register values in old_restart and old_regend.
            Record that current group is inside of all currently active
            groups.
            If the group is inside a loop and it ever matched anything,
            restore its registers to values before the last failed match.
            Restore the registers for the inner groups, too.
          case duplicate: Can back reference to a group that never
            matched if it can match nothing.

Thu Nov 29 11:12:54 1990  Karl Berry  (karl at hayley)

        * regex.c (bcopy, ...): define these if either _POSIX_SOURCE or
          STDC_HEADERS is defined; same for including <stdlib.h>.

Sat Oct  6 16:04:55 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (struct re_pattern_buffer): Changed field comments.

        * regex.c (re_compile_pattern): Allow a `$' to precede an
        alternation operator (`|' or `\|').
        Disallow `^' and/or `$' in empty groups if the syntax bit
        RE_NO_EMPTY_GROUPS is set.
        Wait until have parsed a valid `\{...\}' interval expression
        before testing RE_CONTEXTUAL_INVALID_OPS to see if it's
        invalidated by that.
        Don't use RE_NO_BK_CURLY_BRACES to test whether or not a validly
        parsed interval expression is invalid if it has no preceding re;
        rather, use RE_CONTEXTUAL_INVALID_OPS.
        If an interval parses, but there is no preceding regular
        expression, yet the syntax bit RE_CONTEXTUAL_INDEP_OPS is set,
        then that interval can match the empty regular expression; if
        the bit isn't set, then the characters in the interval
        expression are parsed as themselves (sans the backslashes).
        In unfetch_interval case: Moved PATFETCH to above the test for
        RE_NO_BK_CURLY_BRACES being set, which would force a goto
        normal_backslash; the code at both normal_backsl and normal_char
        expect a character in `c.'

Sun Sep 30 11:13:48 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h: Changed some comments to use the terms used in the
        documentation.
        (RE_CONTEXTUAL_INDEP_OPS): Changed name from `RE_CONTEXT_INDEP_OPS'.
        (RE_LISTS_NOT_NEWLINE): Changed name from `RE_HAT_NOT_NEWLINE.'
        (RE_ANCHOR_NOT_NEWLINE): Added this syntax bit.
        (RE_NO_EMPTY_GROUPS): Added this syntax bit.
        (RE_NO_HYPHEN_RANGE_END): Deleted this syntax bit.
        (RE_SYNTAX_...): Reformatted.
        (RE_SYNTAX_POSIX_BASIC, RE_SYNTAX_EXTENDED): Added syntax bits
        RE_ANCHOR_NOT_NEWLINE and RE_NO_EMPTY_GROUPS, and deleted
        RE_NO_HYPHEN_RANGE_END.
        (RE_SYNTAX_POSIX_EXTENDED): Added syntax bit RE_DOT_NOT_NULL.

        * regex.c (bcopy, bcmp, bzero): Define if _POSIX_SOURCE is defined.
        (_POSIX_SOURCE): ifdef this, #include <stdlib.h>
        (#ifdef emacs): Changed comment of the #endif for the its #else
        clause to be `not emacs', not `emacs.'
        (no_pop_jump): Changed name from `jump'.
        (pop_failure_jump): Changed name from `finalize_jump.'
        (maybe_pop_failure_jump): Changed name from `maybe_finalize_jump'.
        (no_pop_jump_n): Changed name from `jump_n.'
        (EXTEND_BUFFER): Use shift instead of multiplication to double
        buf->allocated.
        (DO_RANGE, recompile_pattern): Added macro to set the list bits
        for a range.
        (re_compile_pattern): Fixed grammar problems in some comments.
        Checked that RE_NO_BK_VBAR is set to make `$' valid before a `|'
        and not set to make it valid before a `\|'.
        Checked that RE_NO_BK_PARENS is set to make `$' valid before a ')'
        and not set to make it valid before a `\)'.
        Disallow ranges starting with `-', unless the range is the
        first item in a list, rather than disallowing ranges which end
        with `-'.
        Disallow empty groups if the syntax bit RE_NO_EMPTY_GROUPS is set.
        Disallow nothing preceding `{' and `\{' if they represent the
        open-interval operator and RE_CONTEXTUAL_INVALID_OPS is set.
        (register_info_type): typedef-ed this using `struct register_info.'
        (SET_REGS_MATCHED): Compacted the code.
        (re_match_2): Made it fail if back reference a group which we've
        never matched.
        Made `^' not match a newline if the syntax bit
        RE_ANCHOR_NOT_NEWLINE is set.
        (really_fail): Added this label so could force a final fail that
        would not try to use the failure stack to recover.

Sat Aug 25 14:23:01 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_CONTEXTUAL_OPS): Changed name from RE_CONTEXT_OPS.
          (global): Rewrote comments and rebroke some syntax #define lines.

        * regex.c (isgraph): Added definition for sequents.
        (global): Now refer to character set lists as ``lists.''
        Rewrote comments containing ``\('' or ``\)'' to now refer to
        ``groups.''
        (RE_CONTEXTUAL_OPS): Changed name from RE_CONTEXT_OPS.

        (re_compile_pattern): Expanded header comment.

Sun Jul 15 14:50:25 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_CONTEX_INDEP_OPS): the comment's sense got turned
        around when we changed how it read; changed it to be correct.

Sat Jul 14 16:38:06 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NO_EMPTY_BK_REF): changed name to
        RE_NO_MISSING_BK_REF, as this describes it better.

        * regex.c (re_compile_pattern): changed RE_NO_EMPTY_BK_REF
        to RE_NO_MISSING_BK_REF, as above.

Thu Jul 12 11:45:05 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.h (RE_NO_EMPTY_BRACKETS): removed this syntax bit, as
        bracket expressions should *never* be empty regardless of the
        syntax.  Removes this bit from RE_SYNTAX_POSIX_BASIC and
        RE_SYNTAX_POSIX_EXTENDED.

        * regex.c (SET_LIST_BIT): in the comment, now refer to character
        sets as (non)matching sets, as bracket expressions can now match
        other things in addition to characters.
        (re_compile_pattern): refer to groups as such instead of `\(...\)'
        or somesuch, because groups can now be enclosed in either plain
        parens or backslashed ones, depending on the syntax.
        In the '[' case, added a boolean just_had_a_char_class to detect
        whether or not a character class begins a range (which is invalid).
        Restore way of breaking out of a bracket expression to original way.
        Add way to detect a range if the last thing in a bracket
        expression was a character class.
        Took out check for c != ']' at the end of a character class in
        the else clause, as it had already been checked in the if part
        that also checked the validity of the string.
        Set or clear just_had_a_char_class as appropriate.
        Added some comments.  Changed references to character sets to
        ``(non)matching lists.''

Sun Jul  1 12:11:29 1990  Karl Berry  (karl at hayley)

        * regex.h (BYTEWIDTH): moved back to regex.c.

        * regex.h (re_compile_fastmap): removed declaration; this
        shouldn't be advertised.

Mon May 28 15:27:53 1990  Kathy Hargreaves  (kathy at hayley)

        * regex.c (ifndef Sword): Made comments more specific.
        (global): include <stdio.h> so can write fatal messages on
        standard error.  Replaced calls to assert with fprintfs to
        stderr and exit (1)'s.
        (PREFETCH): Reformatted to make more readable.
        (AT_STRINGS_BEG): Defined to test if we're at the beginning of
        the virtual concatenation of string1 and string2.
        (AT_STRINGS_END): Defined to test if at the end of the virtual
        concatenation of string1 and string2.
        (AT_WORD_BOUNDARY): Defined to test if are at a word boundary.
        (IS_A_LETTER(d)): Defined to test if the contents of the pointer D
        is a letter.
        (re_match_2): Rewrote the wordbound, notwordbound, wordbeg, wordend,
        begbuf, and endbuf cases in terms of the above four new macros.
        Called SET_REGS_MATCHED in the matchsyntax, matchnotsyntax,
        wordchar, and notwordchar cases.

Mon May 14 14:49:13 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c (re_search_2): Fixed RANGE to not ever take STARTPOS
        outside of virtual concatenation of STRING1 and STRING2.
        Updated header comment as to this.
    (re_match_2): Clarified comment about MSTOP in header.

Sat May 12 15:39:00 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c (re_search_2): Checked for out-of-range STARTPOS.
        Added comments.
    When searching backwards, not only get the character with which
        to compare to the fastmap from string2 if the starting position
        >= size1, but also if size1 is zero; this is so won't get a
        segmentation fault if string1 is null.
        Reformatted code at label advance.

Thu Apr 12 20:26:21 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.h: Added #pragma once and #ifdef...endif __REGEXP_LIBRARY.
        (RE_EXACTN_VALUE): Added for search.c to use.
        Reworded some comments.

        regex.c: Punctuated some comments correctly.
        (NULL): Removed this.
        (RE_EXACTN_VALUE): Added for search.c to use.
    (<ctype.h>): Moved this include to top of file.
    (<assert.h>): Added this include.
        (struct regexpcode): Assigned 0 to unused and 1 to exactn
        because of RE_EXACTN_VALUE.
        Added comment.
        (various macros): Lined up backslashes near end of line.
    (insert_jump): Cleaned up the header comment.
        (re_search): Corrected the header comment.
        (re_search_2): Cleaned up and completed the header comment.
        (re_max_failures): Updated comment.
        (struct register_info): Constructed as bits so as to save space
        on the stack when pushing register information.
        (IS_ACTIVE): Macro for struct register_info.
        (MATCHED_SOMETHING): Macro for struct register_info.
        (NUM_REG_ITEMS): How many register information items for each
        register we have to push on the stack at each failure.
        (MAX_NUM_FAILURE_ITEMS): If push all the registers on failure,
        this is how many items we push on the stack.
    (PUSH_FAILURE_POINT): Now pushes whether or not the register is
        currently active, and whether or not it matched    something.
    Checks that there's enough space allocated to accomodate all the
        items we currently want to push. (Before, a test for an empty
        stack sufficed because we always pushed and popped the same
        number of items).
        Replaced ``2'' with MAX_NUM_FAILURE_POINTS when ``2'' refers
        to how many things get pushed on the stack each time.
        When copy the stack into the newly allocated storage, now only copy
        the area in use.
        Clarified comment.
        (POP_FAILURE_POINT): Defined to use in places where put number
        of registers on the stack into a variable before using it to
        decrement the stack, so as to not confuse the compiler.
        (IS_IN_FIRST_STRING): Defined to check if a pointer points into
        the first string.
        (SET_REGS_MATCHED): Changed to use the struct register_info
        bits; also set the matched-something bit to false if the
        register isn't currently active. (This is a redundant setting.)
        (re_match_2): Cleaned up and completed the header comment.
        Updated the failure stack comment.
        Replaced the ``2'' with MAX_NUM_FAILURE_ITEMS in the static
        allocation of initial_stack, because now more than two (now up
        to MAX_FAILURE_ITEMS) items get pushed on the failure stack each
        time.
        Ditto for stackb.
        Trashed restart_seg1, regend_seg1, best_regstart_seg1, and
        best_regend_seg1 because they could have erroneous information
        in them, such as when matching ``a'' (in string1) and ``ab'' (in
        string2) with ``(a)*ab''; before using IS_IN_FIRST_STRING to see
        whether or not the register starts or ends in string1,
        regstart[1] pointed past the end of string1, yet regstart_seg1
        was 0!
        Added variable reg_info of type struct register_info to keep
        track of currently active registers and whether or not they
    currently match anything.
        Commented best_regs_set.
        Trashed reg_active and reg_matched_something and put the
        information they held into reg_info; saves space on the stack.
        Replaced NULL with '\000'.
        In begline case, compacted the code.
        Used assert to exit if had an internal error.
    In begbuf case, because now force the string we're working on
        into string2 if there aren't two strings, now allow d == string2
        if there is no string1 (and the check for that is size1 == 0!);
        also now succeeds if there aren't any strings at all.
    (main, ifdef canned): Put test type into a variable so could
        change it while debugging.

Sat Mar 24 12:24:13 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c (GET_UNSIGNED_NUMBER): Deleted references to num_fetches.
        (re_compile_pattern): Deleted num_fetches because could keep
        track of the number of fetches done by saving a pointer into the
        pattern.
    Added variable beg_interval to be used as a pointer, as above.
        Assert that beg_interval points to something when it's used as above.
        Initialize succeed_n's to lower_bound because re_compile_fastmap
        needs to know it.
        (re_compile_fastmap): Deleted unnecessary variable is_a_jump_n.
        Added comment.
        (re_match_2): Put number of registers on the stack into a
        variable before using it to decrement the stack, so as to not
        confuse the compiler.
        Updated comments.
        Used error routine instead of printf and exit.
        In exactn case, restored longer code from ``original'' regex.c
        which doesn't test translate inside a loop.

    * regex.h: Moved #define NULL and the enum regexpcode definition
        and to regex.c.  Changed some comments.

        regex.c (global): Updated comments about compiling and for the
        re_compile_pattern jump routines.
        Added #define NULL and the enum regexpcode definition (from
        regex.h).
        (enum regexpcode): Added set_number_at to reset the n's of
        succeed_n's and jump_n's.
        (re_set_syntax): Updated its comment.
    (re_compile_pattern): Moved its heading comment to after its macros.
        Moved its include statement to the top of the file.
        Commented or added to comments of its macros.
    In start_memory case: Push laststart value before adding
        start_memory and its register number to the buffer, as they
        might not get added.
    Added code to put a set_number_at before each succeed_n and one
        after each jump_n; rewrote code in what seemed a more
        straightforward manner to put all these things in the pattern so
        the succeed_n's would correctly jump to the set_number_at's of
        the matching jump_n's, and so the jump_n's would correctly jump
        to after the set_number_at's of the matching succeed_n's.
    Initialize succeed_n n's to -1.
        (insert_op_2): Added this to insert an operation followed by
        two integers.
        (re_compile_fastmap): Added set_number_at case.
        (re_match_2): Moved heading comment to after macros.
        Added mention of REGS to heading comment.
        No longer turn a succeed_n with n = 0 into an on_failure_jump,
        because n needs to be reset each time through a loop.
        Check to see if a succeed_n's n is set by its set_number_at.
    Added set_number_at case.
    Updated some comments.
    (main): Added another main to run posix tests, which is compiled
        ifdef both test and canned.  (Old main is still compiled ifdef
        test only).

Tue Mar 19 09:22:55 1990 Kathy Hargreaves (kathy at hayley)

    * regex.[hc]: Change all instances of the word ``legal'' to
    ``valid'' and all instances of ``illegal'' to ``invalid.''

Sun Mar  4 12:11:31 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.h: Added syntax bit RE_NO_EMPTY_RANGES which is set if
        an ending range point has to collate higher or equal to the
        starting range point.
        Added syntax bit RE_NO_HYPHEN_RANGE_END which is set if a hyphen
        can't be an ending range point.
        Set to two above bits in RE_SYNTAX_POSIX_BASIC and
        RE_SYNTAX_POSIX_EXTENDED.

        regex.c: (re_compile_pattern): Don't allow empty ranges if the
        RE_NO_EMPTY_RANGES syntax bit is set.
        Don't let a hyphen be a range end if the RE_NO_HYPHEN_RANGE_END
    syntax bit is set.
    (ESTACK_PUSH_2): renamed this PUSH_FAILURE_POINT and made it
        push all the used registers on the stack, as well as the number
        of the highest numbered register used, and (as before) the two
        failure points.
    (re_match_2): Fixed up comments.
        Added arrays best_regstart[], best_regstart_seg1[], best_regend[],
        and best_regend_seg1[] to keep track of the best match so far
        whenever reach the end of the pattern but not the end of the
        string, and there are still failure points on the stack with
        which to backtrack; if so, do the saving and force a fail.
    If reach the end of the pattern but not the end of the string,
        but there are no more failure points to try, restore the best
        match so far, set the registers and return.
    Compacted some code.
    In stop_memory case, if the subexpression we've just left is in
        a loop, push onto the stack the loop's on_failure_jump failure
        point along with the current pointer into the string (d).
        In finalize_jump case, in addition to popping the failure
        points, pop the saved registers.
    In the fail case, restore the registers, as well as the failure
        points.

Sun Feb 18 15:08:10 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c: (global): Defined a macro GET_BUFFER_SPACE which
    makes sure you have a specified number of buffer bytes
        allocated.
        Redefined the macro BUFPUSH to use this.
        Added comments.

        (re_compile_pattern): Call GET_BUFFER_SPACE before storing or
        inserting any jumps.

    (re_match_2): Set d to string1 + pos and dend to end_match_1
        only if string1 isn't null.
    Force exit from a loop if it's around empty parentheses.
        In stop_memory case, if found some jumps, increment p2 before
        extracting address to which to jump. Also, don't need to know
        how many more times can jump_n.
    In begline case, d must equal string1 or string2, in that order,
        only if they are not null.
        In maybe_finalize_jump case, skip over start_memorys' and
        stop_memorys' register numbers, too.

Thu Feb 15 15:53:55 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c (BUFPUSH): off by one goof in deciding whether to
    EXTEND_BUFFER.

Wed Jan 24 17:07:46 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.h: Moved definition of NULL to here.
    Got rid of ``In other words...'' comment.
    Added to some comments.

    regex.c: (re_compile_pattern): Tried to bulletproof some code,
        i.e., checked if backward references (e.g., p[-1]) were within
        the range of pattern.

        (re_compile_fastmap): Fixed a bug in succeed_n part where was
        getting the amount to jump instead of how many times to jump.

        (re_search_2): Changed the name of the variable ``total'' to
        ``total_size.''
        Condensed some code.

    (re_match_2): Moved the comment about duplicate from above the
        start_memory case to above duplicate case.

        (global): Rewrote some comments.
        Added commandline arguments to testing.

Wed Jan 17 11:47:27 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.c: (global): Defined a macro STORE_NUMBER which stores a
        number into two contiguous bytes.  Also defined STORE_NUMBER_AND_INCR
    which does the same thing and then increments the pointer to the
    storage place to point after the number.
        Defined a macro EXTRACT_NUMBER which extracts a number from two
        continguous bytes.  Also defined EXTRACT_NUMBER_AND_INCR which
        does the same thing and then increments the pointer to the
        source to point to after where the number was.

Tue Jan 16 12:09:19 1990  Kathy Hargreaves  (kathy at hayley)

    * regex.h: Incorporated rms' changes.
    Defined RE_NO_BK_REFS syntax bit which is set when want to
        interpret back reference patterns as literals.
        Defined RE_NO_EMPTY_BRACKETS syntax bit which is set when want
        empty bracket expressions to be illegal.
        Defined RE_CONTEXTUAL_ILLEGAL_OPS syntax bit which is set when want
    it to be illegal for *, +, ? and { to be first in an re or come
        immediately after a | or a (, and for ^ not to appear in a
        nonleading position and $ in a nontrailing position (outside of
        bracket expressions, that is).
        Defined RE_LIMITED_OPS syntax bit which is set when want +, ?
        and | to always be literals instead of ops.
        Fixed up the Posix syntax.
        Changed the syntax bit comments from saying, e.g., ``0 means...''
        to ``If this bit is set, it means...''.
        Changed the syntax bit defines to use shifts instead of integers.

        * regex.c: (global): Incorporated rms' changes.

        (re_compile_pattern): Incorporated rms' changes
        Made it illegal for a $ to appear anywhere but inside a bracket
        expression or at the end of an re when RE_CONTEXTUAL_ILLEGAL_OPS
        is set. Made the same hold for $ except it has to be at the
        beginning of an re instead of the end.
    Made the re "[]" illegal if RE_NO_EMPTY_BRACKETS is set.
        Made it illegal for | to be first or last in an re, or immediately
        follow another | or a (.
        Added and embellished some comments.
    Allowed \{ to be interpreted as a literal if RE_NO_BK_CURLY_BRACES
        is set.
        Made it illegal for *, +, ?, and { to appear first in an re, or
        immediately follow a | or a ( when RE_CONTEXTUAL_ILLEGAL_OPS is set.
    Made back references interpreted as literals if RE_NO_BK_REFS is set.
        Made recursive intervals either illegal (if RE_NO_BK_CURLY_BRACES
        isn't set) or interpreted as literals (if is set), if RE_INTERVALS
        is set.
    Made it treat +, ? and | as literals if RE_LIMITED_OPS is set.
        Cleaned up some code.

Thu Dec 21 15:31:32 1989  Kathy Hargreaves  (kathy at hayley)

    * regex.c: (global): Moved RE_DUP_MAX to regex.h and made it
    equal 2^15 - 1 instead of 1000.
        Defined NULL to be zero.
        Moved the definition of BYTEWIDTH to regex.h.
        Made the global variable obscure_syntax nonstatic so the tests in
        another file could use it.

        (re_compile_pattern): Defined a maximum length (CHAR_CLASS_MAX_LENGTH)
        for character class strings (i.e., what's between the [: and the
        :]'s).
    Defined a macro SET_LIST_BIT(c) which sets the bit for C in a
        character set list.
        Took out comments that EXTEND_BUFFER clobbers C.
        Made the string "^" match itself, if not RE_CONTEXT_IND_OPS.
    Added character classes to bracket expressions.
        Change the laststart pointer saved with the start of each
        subexpression to point to start_memory instead of after the
        following register number.  This is because the subexpression
        might be in a loop.
        Added comments and compacted some code.
    Made intervals only work if preceded by an re matching a single
        character or a subexpression.
        Made back references to nonexistent subexpressions illegal if
        using POSIX syntax.
    Made intervals work on the last preceding character of a
        concatenation of characters, e.g., ab{0,} matches abbb, not abab.
    Moved macro PREFETCH to outside the routine.

    (re_compile_fastmap): Added succeed_n to work analogously to
        on_failure_jump if n is zero and jump_n to work analogously to
        the other backward jumps.

        (re_match_2): Defined macro SET_REGS_MATCHED to set which
        current subexpressions had matches within them.
        Changed some comments.
    Added reg_active and reg_matched_something arrays to keep track
        of in which subexpressions currently have matched something.
        Defined MATCHING_IN_FIRST_STRING and replaced ``dend == end_match_1''
        with it to make code easier to understand.
    Fixed so can apply * and intervals to arbitrarily nested
        subexpressions.  (Lots of previous bugs here.)
    Changed so won't match a newline if syntax bit RE_DOT_NOT_NULL is set.
        Made the upcase array nonstatic so the testing file could use it also.

        (main.c): Moved the tests out to another file.

    (tests.c): Moved all the testing stuff here.

Sat Nov 18 19:30:30 1989  Kathy Hargreaves  (kathy at hayley)

        * regex.c: (re_compile_pattern): Defined RE_DUP_MAX, the maximum
        number of times an interval can match a pattern.
        Added macro GET_UNSIGNED_NUMBER (used to get below):
        Added variables lower_bound and upper_bound for upper and lower
        bounds of intervals.
        Added variable num_fetches so intervals could do backtracking.
    Added code to handle '{' and "\{" and intervals.
    Added to comments.

        (store_jump_n): (Added) Stores a jump with a number following the
        relative address (for intervals).

        (insert_jump_n): (Added) Inserts a jump_n.

        (re_match_2): Defined a macro ESTACK_PUSH_2 for the error stack;
        it checks for overflow and reallocates if necessary.

    * regex.h: Added bits (RE_INTERVALS and RE_NO_BK_CURLY_BRACES)
    to obscure syntax to indicate whether or not
    a syntax handles intervals and recognizes either \{ and
    \} or { and } as operators.  Also added two syntaxes
    RE_SYNTAX_POSIX_BASIC and RE_POSIX_EXTENDED and two command codes
        to the enumeration regexpcode; they are succeed_n and jump_n.

Sat Nov 18 19:30:30 1989  Kathy Hargreaves  (kathy at hayley)

    * regex.c: (re_compile_pattern): Defined INIT_BUFF_SIZE to get rid
        of repeated constants in code.  Tested with value 1.
    Renamed PATPUSH as BUFPUSH, since it pushes things onto the
        buffer, not the pattern.  Also made this macro extend the buffer
        if it's full (so could do the following):
        Took out code at top of loop that checks to see if buffer is going
        to be full after 10 additions (and reallocates if necessary).

        (insert_jump): Rearranged declaration lines so comments would read
        better.

    (re_match_2): Compacted exactn code and added more comments.

    (main): Defined macros TEST_MATCH and MATCH_SELF to do
        testing; took out loop so could use these instead.

Tue Oct 24 20:57:18 1989  Kathy Hargreaves  (kathy at hayley)

    * regex.c (re_set_syntax): Gave argument `syntax' a type.
        (store_jump, insert_jump): made them void functions.

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