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NEWS
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1994-02-22
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Changes between release 2.4.6 (04Jan94) and release 2.4.5:
- Linking with -lfl no longer required if your program includes
its own yywrap() and main() functions. (This change will cause
problems if you have a non-ANSI compiler on a system for which
sizeof(int) != sizeof(void*) or sizeof(int) != sizeof(size_t).)
- The use of 'extern "C++"' in FlexLexer.h has been modified to
get around an incompatibility with g++'s header files.
Changes between release 2.4.5 (11Dec93) and release 2.4.4:
- Fixed bug breaking C++ scanners that use REJECT or variable
trailing context.
- Fixed serious input problem for interactive scanners on
systems for which char is unsigned.
- Fixed bug in incorrectly treating '$' operator as variable
trailing context.
- Fixed bug in -CF table representation that could lead to
corrupt tables.
- Fixed fairly benign memory leak.
- Added `extern "C++"' wrapper to FlexLexer.h header. This
should overcome the g++ 2.5.X problems mentioned in the
NEWS for release 2.4.3.
- Changed #include of FlexLexer.h to use <> instead of "".
- Added feature to control whether the scanner attempts to
refill the input buffer once it's exhausted. This feature
will be documented in the 2.5 release.
Changes between release 2.4.4 (07Dec93) and release 2.4.3:
- Fixed two serious bugs in scanning 8-bit characters.
- Fixed bug in YY_USER_ACTION that caused it to be executed
inappropriately (on the scanner's own internal actions, and
with incorrect yytext/yyleng values).
- Fixed bug in pointing yyin at a new file and resuming scanning.
- Portability fix regarding min/max/abs macros conflicting with
function definitions in standard header files.
- Added a virtual LexerError() method to the C++ yyFlexLexer class
for reporting error messages instead of always using cerr.
- Added warning in flexdoc that the C++ scanning class is presently
experimental and subject to considerable change between major
releases.
Changes between release 2.4.3 (03Dec93) and release 2.4.2:
- Fixed bug causing fatal scanner messages to fail to print.
- Fixed things so FlexLexer.h can be included in other C++
sources. One side-effect of this change is that -+ and -CF
are now incompatible.
- libfl.a now supplies private versions of the the <string.h>/
<strings.h> string routines needed by flex and the scanners
it generates, to enhance portability to some BSD systems.
- More robust solution to 2.4.2's flexfatal() bug fix.
- Added ranlib of installed libfl.a.
- Some lint tweaks.
- NOTE: problems have been encountered attempting to build flex
C++ scanners using g++ version 2.5.X. The problem is due to an
unfortunate heuristic in g++ 2.5.X that attempts to discern between
C and C++ headers. Because FlexLexer.h is installed (by default)
in /gnu/include and not /gnu/lib/g++-include, g++ 2.5.X
decides that it's a C header :-(. So if you have problems, install
the header in /gnu/lib/g++-include instead.
Changes between release 2.4.2 (01Dec93) and release 2.4.1:
- Fixed bug in libfl.a referring to non-existent "flexfatal" function.
- Modified to produce both compress'd and gzip'd tar files for
distributions (you probably don't care about this change!).
Changes between release 2.4.1 (30Nov93) and release 2.3.8:
- The new '-+' flag instructs flex to generate a C++ scanner class
(thanks to Kent Williams). flex writes an implementation of the
class defined in FlexLexer.h to lex.yy.cc. You may include
multiple scanner classes in your program using the -P flag. Note
that the scanner class also provides a mechanism for creating
reentrant scanners. The scanner class uses C++ streams for I/O
instead of FILE*'s (thanks to Tom Epperly). If the flex executable's
name ends in '+' then the '-+' flag is automatically on, so creating
a symlink or copy of "flex" to "flex++" results in a version of
flex that can be used exclusively for C++ scanners.
Note that without the '-+' flag, flex-generated scanners can still
be compiled using C++ compilers, though they use FILE*'s for I/O
instead of streams.
See the "GENERATING C++ SCANNERS" section of flexdoc for details.
- The new '-l' flag turns on maximum AT&T lex compatibility. In
particular, -l includes support for "yylineno" and makes yytext
be an array instead of a pointer. It does not, however, do away
with all incompatibilities. See the "INCOMPATIBILITIES WITH LEX
AND POSIX" section of flexdoc for details.
- The new '-P' option specifies a prefix to use other than "yy"
for the scanner's globally-visible variables, and for the
"lex.yy.c" filename. Using -P you can link together multiple
flex scanners in the same executable.
- The distribution includes a "texinfo" version of flexdoc.1,
contributed by Roland Pesch (thanks also to Marq Kole, who
contributed another version). It has not been brought up to
date, but reflects version 2.3. See MISC/flex.texinfo.
The flex distribution will soon include G.T. Nicol's flex
manual; he is presently bringing it up-to-date for version 2.4.
- yywrap() is now a function, and you now *must* link flex scanners
with libfl.a.
- Site-configuration is now done via an autoconf-generated
"configure" script contributed by Francois Pinard.
- Scanners now use fread() (or getc(), if interactive) and not
read() for input. A new "table compression" option, -Cr,
overrides this change and causes the scanner to use read()
(because read() is a bit faster than fread()). -f and -F
are now equivalent to -Cfr and -CFr; i.e., they imply the
-Cr option.
- In the blessed name of POSIX compliance, flex supports "%array"
and "%pointer" directives in the definitions (first) section of
the scanner specification. The former specifies that yytext
should be an array (of size YYLMAX), the latter, that it should
be a pointer. The array version of yytext is universally slower
than the pointer version, but has the advantage that its contents
remain unmodified across calls to input() and unput() (the pointer
version of yytext is, still, trashed by such calls).
"%array" cannot be used with the '-+' C++ scanner class option.
- The new '-Ca' option directs flex to trade off memory for
natural alignment when generating a scanner's tables. In
particular, table entries that would otherwise be "short"
become "long".
- The new '-h' option produces a summary of the flex flags.
- The new '-V' option reports the flex version number and exits.
- The new scanner macro YY_START returns an integer value
corresponding to the current start condition. You can return
to that start condition by passing the value to a subsequent
"BEGIN" action. You also can implement "start condition stacks"
by storing the values in an integer stack.
- You can now redefine macros such as YY_INPUT by just #define'ing
them to some other value in the first section of the flex input;
no need to first #undef them.
- flex now generates warnings for rules that can't be matched.
These warnings can be turned off using the new '-w' flag. If
your scanner uses REJECT then you will not get these warnings.
- If you specify the '-s' flag but the default rule can be matched,
flex now generates a warning.
- "yyleng" is now a global, and may be modified by the user (though
doing so and then using yymore() will yield weird results).
- Name definitions in the first section of a scanner specification
can now include a leading '^' or trailing '$' operator. In this
case, the definition is *not* pushed back inside of parentheses.
- Scanners with compressed tables are now "interactive" (-I option)
by default. You can suppress this attribute (which makes them
run slightly slower) using the new '-B' flag.
- Flex now generates 8-bit scanners by default, unless you use the
-Cf or -CF compression options (-Cfe and -CFe result in 8-bit
scanners). You can force it to generate a 7-bit scanner using
the new '-7' flag. You can build flex to