I'd like to run a few lines of code on each instance of a string of a particular form. To accomplish this I've been using a regex of the form:

$s =~ /(string)(?{
  print $^N, $/;
})(?!)/;

[download]

While this works to print all occurances of the string in question (see Global Regex sans //g), I cannot seem to get this to work in list (or perhaps array) context:

my @letters = ('a'..'z');
for my $letter (0..$#letters) {
  $letters[$letter] =~ /(?{ print $letter })(?!)/;
}

[download]

The code seems to run each iteration; however instead of printing the current value of $letter, it returns the following error:

Use of uninitialized value in print at (re_eval 1) line 1.

As I type this I wonder if the regex and the embeded code are being compiled prior to the instantion of the variable? I tried running it through Deparse, but it appeared to be more or less unaltered. Should this be the case, I'd surmise it happens afterwards -- perhaps at runtime?

How can I print the current value of the iteration from within the regex -- preferrably sans eval?

In reply to Iterating over code embeded in regex by eibwen

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