Thanks a lot, I wouldn't have thought myself to check the variant that you suggested. There are about 30 (plus or minus) key-value pairs in my HoA, and, 'external conditions' being constant during a single replacement, it can be 'flattened' to a hash -- it means your pattern will have 30 alterations. Will it be more efficient than my regexp i.e. with code injection? Here's the test:

use strict;
use warnings;
use 5.020;
use String::Random 'random_string';
use Benchmark 'cmpthese';

my $s = random_string( 'b' x 10000 );

my %h = map { chr, chr( $_ + 30 + rand 10) } 0 .. 29;
my $re = join '|', 
    map { quotemeta( $_.$h{$_} ) } keys %h;
    
my ( $s1, $s2 );

cmpthese( -5, {
    1 => sub { $_ = $s; s/([\x00-\x1D])(.)(?(?{ $2 ne $h{$1} })(*FAIL)
+)/xx/sg; $s1 = $_ },
    2 => sub { $_ = $s; s/$re/xx/sg; $s2 = $_ },
} );

say 'OK' if $s1 eq $s2;

__END__

     Rate    1    2
1  1028/s   -- -91%
2 11069/s 977%   --
OK

[download]

It's absolutely wonderful there are sites like this one.

In reply to Re^2: Using sub-matches to interpolate hash keys (array indices)? by vr
in thread Using sub-matches to interpolate hash keys (array indices)? by vr

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