Re: Regex bug? matching multiple newline with /m

$ is a zero-width match, it does not consume a \n;

[rick@ry ~]$ perl -e 'use strict; printf "%s\n", "ab\nab\n" =~ /^ab$ab
+$/m'
Global symbol "$ab" requires explicit package name (did you forget to 
+declare "my $ab"?) at -e line 1.
Execution of -e aborted due to compilation errors.
[rick@ry ~]$
[download]

Try adding the 'use strict;' to your other examples to see what they are really doing.

Comment on Re: Regex bug? matching multiple newline with /m Download Code

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Re^2: Regex bug? matching multiple newline with /m by NERDVANA (Deacon) on Aug 09, 2021 at 10:41 UTC
Ha, yes bitten by interpolation. Thanks. Now I'm wondering how many times in the past I've had difficulties with a multiline regex and it was due to the incorrect assumption that it would consume the \n...	[reply]
Re^3: Regex bug? matching multiple newline with /m by AnomalousMonk (Archbishop) on Aug 09, 2021 at 14:51 UTC
... bitten by interpolation. Perhaps better to say "bitten by failure to enable strict" (and I would also recommend warnings). Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]
Re^3: Regex bug? matching multiple newline with /m by BillKSmith (Monsignor) on Aug 14, 2021 at 15:23 UTC
The problem with interpolation is covered in the documentation for `/PATTERN/msixpodualngc` in Regexp Quote Like Operators. If "'" is used as the delimiter, no variable interpolation is done. This is not enough to solve your problem with the newline because `$` is a zero width assertion. Assertions Besides "^" and "$", Perl defines the following zero-width assertions: In this case, it is probably best to match the newline explicitly and not use the anchor at all. Bill	[reply] [d/l] [select]


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