NAME
    Perl::Stripper - Yet another PPI-based Perl source code stripper

VERSION
    This document describes version 0.10 of Perl::Stripper (from Perl
    distribution Perl-Stripper), released on 2017-07-11.

SYNOPSIS
     use Perl::Stripper;

     my $stripper = Perl::Stripper->new(
         #maintain_linum => 1, # the default, keep line numbers unchanged
         #strip_ws       => 1, # the default, strip extra whitespace
         #strip_comment  => 1, # the default
         #strip_pod      => 1, # the default
         strip_log       => 1, # default is 0, strip Log::Any log statements
     );
     $stripped = $stripper->strip($perl);

DESCRIPTION
    This module is yet another PPI-based Perl source code stripper. Its
    focus is on costumization and stripping meaningful information from
    source code.

ATTRIBUTES
  maintain_linum => BOOL (default: 1)
    If set to true, stripper will try to maintain line numbers so they do
    not change between the unstripped and the stripped version. This is
    useful for debugging.

    Respected by other settings.

  strip_ws => BOOL (default: 1)
    Strip extra whitespace, like indentation, padding, even non-significant
    newlines. Under "maintain_linum", will not strip newlines.

    Not yet implemented.

  strip_comment => BOOL (default: 1) | CODE
    If set to true, will strip comments. Under "maintain_linum" will replace
    comment lines with blank lines.

    Shebang line (e.g. "#!/usr/bin/perl", located at the beginning of
    script) will not be stripped.

    Can also be set to a coderef. Code will be given the PPI comment token
    object and expected to modify the object (e.g. using "set_content()"
    method). See PPI::Token::Comment for more details. Some usage ideas:
    translate comment, replace comment with gibberish, etc.

  strip_log => BOOL (default: 1)
    If set to true, will strip log statements. Useful for removing debugging
    information. Currently supports Log::Any and Log::ger and only looks for
    the following statements:

     $log->LEVEL(...);
     $log->LEVELf(...);
     log_LEVEL(...);
     if ($log->is_LEVEL) { ... }
     if (log_is_LEVEL()) { ... }

    Not all methods are stripped. See "stripped_log_levels".

    Can also be set to a coderef. Code will be given the PPI::Statement
    object and expected to modify it.

    These are currently not stripped:

     if (something && $log->is_LEVEL) { ... }

  stripped_log_levels => ARRAY_OF_STR (default: ['debug', 'trace'])
    Log levels to strip. By default, only "debug" and "trace" are stripped.
    Levels "info" and up are considered important for users (instead of for
    developers only).

  strip_pod => BOOL (default: 1)
    If set to true, will strip POD. Under "maintain_linum" will replace POD
    with blank lines.

    Can also be set to a coderef. Code will be given the PPI POD token
    object and expected to modify the object (e.g. using "set_content()"
    method). See PPI::Token::Pod for more details.Some usage ideas:
    translate POD, convert POD to Markdown, replace POD with gibberish, etc.

METHODS
  new(%attrs) => OBJ
    Constructor.

  $stripper->strip($perl) => STR
    Strip Perl source code. Return the stripped source code.

FAQ
  What is the use of this module?
    This module can be used to remove debugging information (logging
    statements, conditional code) from source code.

    This module can also be employed as part of source code protection
    strategy. In theory you cannot hide source code you deploy to
    users/clients, but you can reduce the usefulness of the deployed source
    code by removing information such as comments and POD (documentation),
    or by mangling subroutine/variable names (removing meaningful original
    subroutine/variable names).

    For compressing source code (reducing source code size), you can try
    Perl::Squish or Perl::Strip.

  But isn't hiding/protecting source code immoral/unethical/ungrateful?
    Discussing hiding/protecting source code in general is really beyond the
    scope of this module's documentation. Please consult elsewhere.

  How about obfuscating by encoding Perl code?
    For example, changing:

     foo();
     bar();

    into:

     $src = base64_decode(...); # optionally multiple rounds
     eval $src;

    This does not really remove meaningful parts of a source code, so I am
    not very interested in this approach. You can send a patch if you want.

  How about changing string into hexadecimal characters? How about ...?
    Other examples similar in spirit would be adding extra parentheses to
    expressions, changing constant numbers into mathematical expressions.

    Again, this does not *remove* meaningful parts of a source code
    (instead, they just transform stuffs). The effect can be reversed
    trivially using Perl::Tidy or B::Deparse. So I am not very interested in
    doing this, but you can send a patch if you want.

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/Perl-Stripper>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-Perl-Stripper>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=Perl-Stripper>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

SEE ALSO
    There are at least two approaches when analyzing/modifying/producing
    Perl code: B-based and PPI-based. In general, B-based modules are orders
    of magnitude faster than PPI-based ones, but each approach has its
    strengths and weaknesses.

    B::Deparse - strips comments and extra newlines

    B::Deobfuscate - like B::Deparse, but can also rename variables. Despite
    its name, if applied to a "normal" Perl code, the effect is obfuscation
    because it removes the original names (and meaning) of variables.

    Perl::Strip - PPI-based, focus on compression.

    Perl::Squish - PPI-based, focus on compression.

AUTHOR
    perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2017, 2015, 2014, 2013, 2012 by
    perlancar@cpan.org.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

