NAME
    post526sigfix - Fixup attribute/signatures code between 5.26 and 5.28+ style

SYNOPSIS
      Usage: post526sigfix [OPTIONS] [FILES]
  
        post526sigfix -u perl526file >perl528file
        post526sigfix -d perl528file >perl526file
        post526sigfix -d --pmc lib/My/Module.pm >lib/My/Module.pmc
        post526sigfix -u -i $(find lib -name '*.pm')
        post526sigfix -d -i --pmc $(find lib -name '*.pm')
  
      Options:
  
        -u, --upgrade    Upgrade 5.26 syntax to 5.28 syntax
        -d, --downgrade  Downgrade 5.28 syntax to 5.26 syntax
        -i, --inplace    Modify target file(s) in place
        --pmc            Generate .pmc w/goto::file to load .pm on other versions

INSTALLING
    There's a fatpacked copy currently available next to this file at:

      http://trout.me.uk/perl/post526sigfix

WORKED EXAMPLE
    Starting with an unpacked List-Lazy-0.3.0 which was the last version to
    have attributes and signatures on the same subroutine, and perl 5.26 and
    5.28 installs with its dependencies installed,

      perl526$ prove -l t # passes
      perl528$ prove -l t # explodes

    Now, if we run

      perl$ post526sigfix -u lib/List/Lazy.pm >lib/List/Lazy.pmc

    then we find that

      perl526$ prove -l t # explodes
      perl528$ prove -l t # passes

    Having tested the upgraded version works, we can upgrade the .pm in
    place -

      perl$ rm lib/List/Lazy.pmc
      perl$ post526sigfix -i -u lib/List/Lazy.pm

    and once again,

      perl526$ prove -l t # explodes
      perl528$ prove -l t # passes

    Now, to complete the fixage, we want to also create a .pmc file for the
    downgrade case, which we can do using either

      perl$ post526sigfix -d --pmc lib/List/Lazy.pm >lib/List/Lazy.pmc

    or the shorter

      perl$ post526sigfix -i -d --pmc lib/List/Lazy.pm

    This now means that as well as the 5.28 compatible .pm file, we have a
    5.26 compatible .pmc file - and that pmc file starts with

      use if $] >= 5.028, 'goto::file', __FILE__;

    so if loaded on a 5.28+ perl, it automatically jumps back to the .pm
    file instead. Which means:

      perl526$ prove -l t # passes
      perl528$ prove -l t # passes

    (with the exception of t/00-compile.t which hardcodes .pm and so misses
    the .pmc on 5.26, but the functional tests do indeed all work)

    Which means that if he ever wants to, YANICK should totally be able to
    switch back to using attributes and signatures on the same subroutine
    again - and now it's (sort of) safe for you to use them both, too!

AUTHOR
    mst - Matt S. Trout (cpan:MSTROUT) <mst@shadowcat.co.uk>

CONTRIBUTORS
    None yet. Well volunteered? :)

COPYRIGHT
    Copyright (c) 2018 the post526sigfix "AUTHOR" and "CONTRIBUTORS" as
    listed above.

LICENSE
    This library is free software and may be distributed under the same
    terms as perl itself.