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Postings from May 2012
The following code: my $count = 80; my $foo = "(.)" x $count; qr/$foo\80/ generates code to match $count characters, and, then the eightieth (as long as $count >= 80). But what should happen for $count = 79? Does anyone disagree that it should raise the fatal error "Reference to nonexistent group in regex"?, which is what happens when we are looking for 8 backreferences but only 7 are present? $ blead -E 'my $count = 7; my $foo = "(.)" x $count; qr/$foo\8/' Reference to nonexistent group in regex; marked by <-- HERE in m/(.)(.)(.)(.)(.)(.)(.)\8 <-- HERE / at -e line 1. If you agree with my claim, then what about $count = 78, ... 3, 2, 1, 0 ? Shouldn't it raise the same error? What in fact happens is that it does match the eightieth backreference for all $count >= 80. But when $count is less than 80, it silently compiles "\00080" in where the "\80" is; that is, it matches a NUL, then the digit 8, then the digit 0. I claim this is a bug, and have written a small patch to fix it. But given the controversy over previous attempts to fix weird cases like this, I thought I had better check it out on the list first.Thread Next