Re: Using qr// with substitution and group-interpolation inthesubstitution part

On 11/21/23 20:08, gordonfish wrote:
> On 10/25/23 10:32, Josef Wolf wrote:
> 
> [...]
> 
>> Basically, I want to do the same as
>>
>>
>>    $data =~ s/^foo (whatever) bar$/bar $1 baz/mg;
>>
>>
>> but with a different interface (because it has to be embedded into a 
>> bigger
>> project), So I have come with this;
>>
>>
>>    sub substitute_lines {
>>        my ($contents, $regex, $subst) = @_;
>>            $contents =~ s/$regex/$subst/mg;
>>            return $contents;
>>        }
>>    }
>>
>>    &substitute_lines ($data, qr/^foo (whatever) bar$/mg, 'bar $1 baz');
>>
>>
>> Which (mostly) works as expected. Unfortunately, this won't 
>> interpolate the
>> matched group $1.
> [...]


---Reposting due to code indents being eaten---


You could so something like:

use feature qw(signatures);

sub substitute_lines($contents, $regex, $subst) {
     $contents =~ s/$regex/$subst->()/emgr;
}

...

substitute_lines
     $data,
     qr/^foo (whatever) bar$/,
     sub { "bar $1 baz" };


This will pass an anonymous sub routine which will be called from s/// 
replacement side thanks to the /e modifier that allows code to be 
executed there.

Also of some note is that the /r modifier is used so that s/// returns 
the resulting string instead of modifying $contents, and being the last 
statement, said resulting string is the return value.

-- 
gordonfish