Suppose you want to see how a hypothetical Perl 5.16 with a method keyword might work. Reading the patch to add method to Perl 5 isn't as fun as using it yourself.

If you're an old hand at patching and building Perl 5, you already know what to do. That leaves about a million of the rest of us.

First, check out a recent bleadperl from Git. Within that directory, check out revision 8bdb331 (as it's the basis of the patch). You can use later revisions, but you may have to massage the patch yourself:

$ git checkoout 8bdb331

Now download the method patch and apply it:

$ patch -p1 < 0001-Added-use-feature-method-and-tests.patch

Everything should apply cleanly. Now you need to configure Perl:

$ sh Configure -de -Dusedevel -Dprefix=$PERLBREW_ROOT/perls/perl-5.13-method

If you don't use perlbrew, you should. With this configuration you can install bleadperl with this patch as if it were a released Perl 5, at least as perlbrew sees it. Change the value of -Dprefix to match your preferred installation directory. After a few moments, you can regenerate the parser and other generated files, then build, test, and install the new Perl yourself:

$ make regen regen_perly $ make test $ make install

If you have trouble building or installing bleadperl, read the included INSTALL file. I cannot provide technical support here; the usual Perl 5 support channels apply (especially if you also have trouble building, testing, or installing bleadperl without this patch).

Then you can use perlbrew to switch to the new Perl 5 ( perlbrew use perl-5.13-method or perlbrew switch perl-5.13-method ) and test it with your favorite code.

Update: improved instructions per oylenshpeegul's comments.