Thanks, ikegami.

The documentation "The range operator (in list context) makes use of the magical auto-increment algorithm if the operands are strings." didn't quite shed any light on it, as I'm already familiar with the magical auto-increment feature.  (But I think hbm got it below, which clarified something that the documenation could possibly use better wording for).

As to the second, however, you say the workaround is to use a "modifiable copy": 

for ('a'..'f') {
   my $letter = $_;  # Make modifiable copy
   ...
}

[download]

But why isn't the my that I'm using here: 

    foreach my $letter ('a' ... 'c', 'd' ... 'f') {
        print " $letter";
        $letter = uc $letter;
    }

[download]

doing exactly that??

Update:  Actually, I see why. Of course, because it's assigning to a modifiable lvalue of the variable. Never mind.

But I'm still curious why this: 

#!/usr/bin/perl -w

use strict;
use warnings;

sub letters {
    foreach my $letter ('a' ... 'c') {
        print " $letter";
        $letter = uc $letter;
    }
    print "\n";
}

letters();
letters();
letters();

[download]

Doesn't exhibit the same behavior? Is it simply that it doesn't undergo the same optimization step you referred to?

s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/

In reply to Re^2: Two Range Operator Anomalies by liverpole
in thread Two Range Operator Anomalies by liverpole

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