Re^2: Evaluate arbitrary boolean expressions

Thanks for the quick response.

In answer to your question: I am only interested in whether the expression I generate is true or false. I do not need to do any algebraic symbolic reduction of the terms.

Comment on Re^2: Evaluate arbitrary boolean expressions

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Re^3: Evaluate arbitrary boolean expressions
by Corion (Patriarch) on Mar 13, 2018 at 11:42 UTC

A simplicistic approach would be to repeatedly apply these three rules to simplify things:

replace F || X with X and T && Y with Y
replace F && X with F and T || Y with T
replace an atomar term within parenthes with that atomar term

#!perl -w
use strict;
my @terms = (
    '( ( T || F ) && T )',
    '( ( T || F ) && ( F && F ))'
);

sub simplify {
    my( $term ) = @_;
    $term =~ s!\s+!!g; # eliminate all whitespace
    my $changed;
    do {
        $changed = 0;
        $changed ||= ($term =~ s!F\|\|!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!\|\|F!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!T\&\&!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!\&\&T!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!F\&\&!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!\&\&F!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!T\|\|!!g);
        #print "$term ($changed)\n";
        $changed ||= ($term =~ s!\|\|T!!g);
        #print "$term ($changed)\n";

        $changed ||= ($term =~ s!\(([FT])\)!$1!g);
        #print "$term ($changed)\n";
    } while $changed;
    return $term
}

for my $t (@terms) {
    print "$t => " . simplify( $t ), "\n";
};
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