p5pRT
commented
19 years ago From david@landgren.net
Created by david@landgren.net
It is possible to use simple expressions in (?{...}) constructs\, such as (?{123})\, the idea being that they could be picked up afterwards by reading the contents of $^R.
When optional (?:...)? patterns are used\, the engine appears to become confused and $^R is set to the value of the expression prior to the optional part. It can be shown that the code blocks are in fact executed. Code with side effects (pushing values onto an array) is run\, and the expected results are observed after the match. The problem occurs only for simple expressions.
This behaviour is seen in 5.005_03\, 5.8.5 and 5.8.6.
There do not appear to be any tests that check how $^R should behave. The following file is an attempt to improve matters.
(The following tests all pass except for the following:
not ok 8 - $^R == 8 # Failed test (./vr at line 21)
$^R is in fact equal to 7).
__TEST_FILE_BEGIN__ use Test::Simple tests => 26;
$^R = undef; ok( 'a' =~ /^a(?{1})(?:b(?{2}))?/\, 'a =~ ab?' ); ok( $^R == 1\, '$^R == 1' );
$^R = undef; ok( 'abc' !~ /^a(?{3})(?:b(?{4}))$/\, 'abc !~ a(?:b)$' ); ok( !defined $^R\, 'undef 2nd' );
$^R = undef; ok( 'ab' =~ /^a(?{5})b(?{6})/\, 'ab =~ ab' ); ok( $^R == 6\, '$^R == 6' );
$^R = undef; ok( 'ab' =~ /^a(?{7})(?:b(?{8}))?/\, 'ab =~ ab?' ); ok( $^R == 8\, '$^R == 8' );
$^R = undef; ok( 'ab' =~ /^a(?{9})b?(?{10})/\, 'ab =~ ab? (2)' ); ok( $^R == 10\, '$^R == 10' );
my @ar; ok( 'ab' =~ /^a(?{push @ar\,11})(?:b(?{push @ar\,12}))?/\, 'ab =~ ab?' ); ok( scalar(@ar) == 2\, 'nr pushed ok' ); ok( ($ar[0] == 11 and $ar[1] == 12)\, 'push contents ok' );
$^R = undef; ok( 'a' !~ /^a(?{13})b(?{14})/\, 'a !~ ab' ); ok( !defined $^R\, 'undef 3rd' );
@ar = (); ok( 'a' !~ /^a(?{push @ar\,15})b(?{push @ar\,16})/\, 'a !~ ab (push)' ); ok( scalar(@ar) == 0\, 'none pushed ok' );
@ar = (); ok( 'abc' !~ /^a(?{push @ar\,17})b(?{push @ar\,18})$/\, 'abc !~ ab$ (push)' ); ok( scalar(@ar) == 0\, 'none pushed ok' );
use vars '@var';
ok( 'ab' =~ /^a(?{push @var\,19})(?:b(?{push @var\,20}))?/\, 'ab =~ ab?' ); ok( scalar(@var) == 2\, 'nr pushed ok' ); ok( ($var[0] == 19 and $var[1] == 20)\, 'push contents ok' );
@var = (); ok( 'a' !~ /^a(?{push @var\,21})b(?{push @var\,22})/\, 'a !~ ab (push)' ); ok( scalar(@var) == 0\, 'none pushed ok' );
@var = (); ok( 'abc' !~ /^a(?{push @var\,23})b(?{push @var\,24})$/\, 'abc !~ ab$ (push)' ); ok( scalar(@var) == 0\, 'none pushed ok' ); __TEST_FILE_END__
Migrated from rt.perl.org#36909 (status was 'resolved')
Searchable as RT36909$