Perl regex replace in same case

Question

If you have a simple regex replace in perl as follows:

($line =~ s/JAM/AAA/g){

how would I modify it so that it looks at the match and makes the replacement the same case as the match for example:

'JAM' would become 'AAA' and 'jam' would become 'aaa'

Answer 1

Unicode-based solution:

use Unicode::UCD qw(charinfo);
my %category_mapping = (
    Lu  # upper-case Letter
        => 'A',
    Ll  # lower-case Letter
        => 'a',
);

join q(), map { $category_mapping{charinfo(ord $_)->{category}} } split //, 'jam';
# returns aaa

join q(), map { $category_mapping{charinfo(ord $_)->{category}} } split //, 'JAM';
# returns AAA

Here the unhandled characters resp. their categories are a bit easier to see than in the other answers.