[tpm] New Regex question - partially solved

[Rob Janes]

ok, if you don't believe me when I say it doesn't work, try it yourself
then.

[robj at rj-ul80vt ~]$ perl -e '$x = "one \t\t two"; print "$x\n"; $x =~
s/(\s)$1+/\1/; print "$x\n";'
one          two
one two
[robj at rj-ul80vt ~]$ perl -e '$x = "one \t\t two"; print "$x\n"; $x =~
s/(\s)\1+/\1/; print "$x\n";'
one          two
one      two

notice that the usage of $1 resulted in a mixed string of whitespace being
substituted.  only the tabs should have been substituted, not everything.

therefore, the $1 in the matching regex resolved to \s not space.

On Sat, Oct 27, 2012 at 11:52 PM, Uri Guttman <uri at stemsystems.com> wrote:

> On 10/27/2012 07:42 PM, Rob Janes wrote:
>
>> Slurp the file and run the second regex.
>>
>> undef $/;
>> $exp = <in>;
>>
> use File::Slurp is much better for that.
>
>
>  $exp =~ s/(\s)\1+/\1/g;
>>
>
> i keep saying to not use \1 in the replacement. it is documented to be
> wrong but supported. don't use it there. use $1
>
> uri
>
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