Front page | perl.perl5.porters |
Postings from November 2011
On 11/26/2011 06:06 PM, Father Chrysostomos via RT wrote:
> On Sat Sep 03 09:42:50 2011, sprout wrote:
>> On Sat Sep 03 07:47:42 2011, peter@peterscott.com wrote:
>>> perlre says:
>>>
>>> "(??{ code })"
>>> [...]
>>> The result of evaluation is considered a regular
>> expression and
>>> matched as if it were inserted instead of this construct.
>> Note
>>> that this means that the contents of capture groups defined
>>> inside
>>> an eval'ed pattern are not available outside of the
>> pattern, and
>>> vice versa, there is no way for the inner pattern to refer
>> to a
>>> capture group defined outside. Thus,
>>>
>>> ('a' x 100)=~/(??{'(.)' x 100})/
>>>
>>> will match, it will not set $1.
>>>
>>> The last assertion is true, however, the one before it appears not
> to be:
>>>
>>> % perl -E '"abc" =~ /(.)(??{say "\$1=$1"; "(.)"})/ and say "\$2=$2"'
>>> $1=a
>>> $2=
>>>
>>> In other words, the subexpression
>>
>> It says ‘inner pattern’, not subexpression. That appears to be true:
>>
>> $ perl -E '"aa" =~ /^(.)(??{say "\$1=$1"; q"(\1)"})/ ? say "\$2=$2" :
>> say "fail"'
>> $1=a
>> fail
>>
>>> *can* access capture groups defined(The code block itself can use C<$1>, etc.,
> to refer to the enclosing patterns capture groups.)
>>> outside itself. Either the documentation or the code should be changed.
>>
>> Maybe the documentation should be clarified. Do you have any suggestions?
>>
>
> I hope I have clarified this sufficiently with commit b271183.
>
I'm afraid I don't understand this "(The code block itself can use
C<$1>, etc., to refer to the enclosing patterns capture groups.)"
Should "patterns" be "pattern's", or is something else intended?
Thread Previous
|
Thread Next