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Postings from February 2013
On 2013-02-17 02:15, demerphq wrote:
> We changed which level of the perl parser handles escapes intended for
> the regex engine.
>
> Previous to this the \x20 would be resolved to a space, and as far as
> the regex engine was concerned the pattern would be " ".
>
> After this change the \x20 would be delivered to the regex engine
> verbatim and the \x20 form would not be recognized by the heuristic
> that handles the " " case.
>
> This change was very desirable for many reasons, and as it doesnt
> actually contradict the docs, unless Ricardo says otherwise I consider
> this Not A Bug.
See some split() cases below. So, #4 should behave as #7..10.
So, the PATTERN "\x20" should be compiled as /\x20/, not as " ".
--
Ruud
$ perl5.14.2 -MData::Dumper -wle '
use constant SPC => "\x20";
sub SPC0 () { "\x20" }
sub SPC1 { "\x20" }
my $SPC = "\x20";
sub p { print shift, ":\t[", join( "][", @_ ), "]" }
$_ = "\x20\x20\x20a b c\x20\x20";
p 1, split undef;
p 2, split;
p 3, split " ";
p 4, split "\x20";
p 5, split SPC;
p 6, split SPC0;
p 7, split SPC1;
p 8, split $SPC;
p 9, split / /;
p 10, split /\x20/;
p 11, split "a";
p 12, split /a/;
'
Use of uninitialized value in regexp compilation at -e line 9.
1: [ ][ ][ ][a][ ][b][ ][c][ ][ ]
2: [a][b][c]
3: [a][b][c]
4: [a][b][c]
5: [a][b][c]
6: [a][b][c]
7: [][][][a][b][c]
8: [][][][a][b][c]
9: [][][][a][b][c]
10: [][][][a][b][c]
11: [ ][ b c ]
12: [ ][ b c ]
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