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NAME

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



SYNOPSIS
     perl -MO=Deparse[,-uPACKAGE][,-p][,-l][,-sLETTERS] prog.pl



DESCRIPTION
     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 -p
     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.



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

     -p  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 -p,
         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).


     -uPACKAGE
         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 -u option. The argument to -u is the name of a
         package, and should follow directly after the 'u'.
         Multiple -u options may be given, separated by commas.
         Note that unlike some other backends, B::Deparse doesn't
         (yet) try to guess automatically when -u is needed --
         you must invoke it yourself.

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

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

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

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

             instead of

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

             The default is not to cuddle.



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



AUTHOR
     Stephen McCamant <alias@mcs.com>, based on an earlier
     version by Malcolm Beattie <mbeattie@sable.ox.ac.uk>.









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