Hi there friends,

We have complicated expressions like this, which may also contain deep nesting:

  ((A & B)' | (A & C & (A & B & D)'));

[download]

Every time we see sub expressions like:
(1)  (A & B)\' and
(2)  (A & C & (A & B & D)')
we have to substitute them with the following:
 !(A & B) for (1) above
and  (A & C & !(A & B & D)) for (2) above.

I wrote the following but it obviously requires some more improvements. Can you help me know what I am doing wrong? 

#!/usr/bin/perl
use strict;
use warnings;

my $x = '((A & B)\' | (A & C & (A & B & D)\'))'; 

print "Given: $x\n"; 

$x =~ s/(\(.*?\))\'/\!$1/g; 

print "Calculated: ",$x,"\n";

[download]

That prints: 

Given: ((A & B)' | (A & C & (A & B & D)')) 
Calculated: (!(A & B) | !(A & C & (A & B & D)))

[download]

The second part of the sub expression is incorrect as my regex match did not do what is intended, which is: substitute  (A & B & D)' with  !(A & C & (A & B & D))
Thank you friends.
Bill Murphy.

In reply to Regex matching and substitution by Learning_Perl_2017

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