File Coverage

blib/lib/Acme/ButFirst.pm

Criterion	Covered	Total	%
statement	13	13	100.0
branch			n/a
condition			n/a
subroutine	5	5	100.0
pod			n/a
total	18	18	100.0

package Acme::ButFirst;

use 5.006;
use strict;
use warnings;

use Filter::Simple;

our $VERSION = '1.00';

# Yes, this is a recursive regexp. ;)

my $block;

$block = qr{
	{					# An open-curly
		(?:
			(?> [^{}]+ )		# Non-curlies no backtracking.
			|
			(??{ $block })		# An embedded block
		)*
	}					# Close-curly
}x;

sub _butfirstify {

	# Continue to re-write our code until no more butfirst
	# sections exist.

	# We enclose each pair of blocks transposed inside their
	# own block.  This allows chained but-firsts and
	# butfirst modifiers on loops to work 'correctly'.

	1 while s{ ($block) \s* but \s* first \s* ($block) }
                 {{$2\n$1}}gxs;

};

# We have to use 'executable' rather than code, as Filter::Simple
# sometimes thinks that 'but \s* first' is a bareword string.
#
# The downside of this is that we may modify some *real* strings
# as well as code.


FILTER_ONLY executable => \&_butfirstify;

1;
__END__