SGI Freeware 1999 August/SGI Freeware 1999 August.iso/dist/fw_perl.idb/usr/freeware/catman/p_man/cat3/B::Deparse.Z/B::Deparse

Text File | 1998-10-28 | 5.3 KB | 199 lines

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     NNNNAAAAMMMMEEEE
      B::Deparse - Perl compiler backend to    produce    perl code

     SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
      ppppeeeerrrrllll ----MMMMOOOO====DDDDeeeeppppaaaarrrrsssseeee[,,,,----uuuu_P_A_C_K_A_G_E][,,,,----pppp][,,,,----llll][,,,,----ssss_L_E_T_T_E_R_S] _p_r_o_g._p_l

     DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
      B::Deparse is    a backend module for the Perl compiler that
      generates perl source    code, based on the internal compiled
      structure that perl itself creates after parsing a program.
      The output of    B::Deparse won't be exactly the    same as    the
      original source, since perl doesn't keep track of comments
      or whitespace, and there isn't a one-to-one correspondence
      between perl's syntactical constructions and their compiled
      form,    but it will often be close. When you use the ----pppp
      option, the output also includes parentheses even when they
      are not required by precedence, which    can make it easy to
      see if perl is parsing your expressions the way you
      intended.

      Please note that this    module is mainly new and untested code
      and is still under development, so it    may change in the
      future.

     OOOOPPPPTTTTIIIIOOOONNNNSSSS
      As with all compiler backend options,    these must follow
      directly after the '-MO=Deparse', separated by a comma but
      not any white    space.

      ----pppp  Print extra parentheses. Without this option, B::Deparse
          includes parentheses in its output only when they    are
          needed, based on the structure of    your program. With ----pppp,
          it uses parentheses (almost) whenever they would be
          legal. This can be useful    if you are used    to LISP, or if
          you want to see how perl parses your input. If you say

          if ($var & 0x7f == 65) {print    "Gimme an A!"}
          print    ($which    ? $a : $b), "\n";
          $name    = $ENV{USER} or    "Bob";

          B::Deparse,-p will print

          if (($var & 0)) {
              print('Gimme an A!')
          };
          (print(($which ? $a :    $b)), '???');
          (($name = $ENV{'USER'}) or '???')

          which probably isn't what    you intended (the '???'    is a
          sign that    perl optimized away a constant value).





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      ----uuuu_P_A_C_K_A_G_E
          Normally,    B::Deparse deparses the    main code of a
          program, all the subs called by the main program (and
          all the subs called by them, recursively), and any other
          subs in the main:: package. To include subs in other
          packages that aren't called directly, such as AUTOLOAD,
          DESTROY, other subs called automatically by perl,    and
          methods, which aren't resolved to    subs until runtime,
          use the ----uuuu option. The argument to ----uuuu is the name    of a
          package, and should follow directly after    the 'u'.
          Multiple ----uuuu options may be given,    separated by commas.
          Note that    unlike some other backends, B::Deparse doesn't
          (yet) try    to guess automatically when ----uuuu is needed --
          you must invoke it yourself.

      ----llll  Add '#line' declarations to the output based on the line
          and file locations of the    original code.

      ----ssss_L_E_T_T_E_R_S
          Tweak the    style of B::Deparse's output. At the moment,
          only one style option is implemented:

      CCCC      Cuddle elsif,    else, and continue blocks. For
          example, print

              if (...) {
               ...
              }    else {
               ...
              }

          instead of

              if (...) {
               ...
              }
              else {
               ...
              }

          The default is not to    cuddle.

     BBBBUUUUGGGGSSSS
      See the 'to do' list at the beginning    of the module file.

     AAAAUUUUTTTTHHHHOOOORRRR
      Stephen McCamant <[e-mail]>, based on an    earlier
      version by Malcolm Beattie <[e-mail]>.







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