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Postings from August 2008
>> And so we have a culture--no, strike that--we have *two*
>> cultures, where they are expecting \t, and \n too, to mean a
>> single character.
> By that argument, you should agree with Damian's admonition that
> one should always use the `/m` modifier on patterns, because that
> will make `^` and `$` behave as programmers from other cultures
> expect, even though in Perl they behave differently, and a Perl
> programmer knows how they do behave in Perl.
First off, I confess to failing to deeply understand where Damian is
coming from there. Therefore, I shall neither agree nor disagree with
what I do not understand. Which means I cannot continue your question.
More specifically, I have myself no acquaintance with any culture where
/^/ means /^/m. Perhaps Damian does. The same applies to /$/ vs /$/m.
So I am quite confortable using ^ in nearly all places, though perhaps
not in /^[^^]/ :).
However, /$/ is trickier for a different reason altogether, and its trouble
is unimproved by /$/m, or by /\Z/ either. It's a bit of a shame that as
/./s means /\p{Any}/ (which is what I more often use now, lamentably
unHoffmaning the commonest thing from a wee 1 to a super 7, even 8 chars),
that /$/s never came to mean /\z/.
Given that I've had to fix this before, as noted in the Changes5.6 log entry:
[ 5296] By: gsar on 2000/02/28 00:00:05
Log: m/.*$/ etc should be m/.*\z/s in many file handling modules; fix
these insidious errors in File::Basename, File::Find and find2perl
(from Tom Christiansen)
TODO: many other modules need to be fixed as well!
Branch: perl
! lib/File/Basename.pm lib/File/Find.pm x2p/find2perl.PL
There is probably something to be learned here, even if I don't quite
understand what Damian's saying. As noted, I do hate insidious errors.
--tom
PS: Don't get me started about use warnings safety on
\p{Any}
\p{Assigned}
\p{UnAssigned}
eg% perl -WE 'say chr(0xfdd0) =~ /\p{Any}/ || 0'
Unicode character 0xfdd0 is illegal at -e line 1.
1
eg% perl -WE 'say chr(0xfdd0) =~ /\p{Assigned}/ || 0'
Unicode character 0xfdd0 is illegal at -e line 1.
0
eg% perl -WE 'say chr(0xfdd0) =~ /\p{UnAssigned}/ || 0'
Unicode character 0xfdd0 is illegal at -e line 1.
1
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