I was playing with some recursive parsing, and made a simple program to parse apart text based on a given list of precedence. I was quite pleased with the result. :)

#!/usr/bin/perl
use warnings;
use strict;
use Data::Dumper;
$Data::Dumper::Terse=1;


my $precedence=[qr/&&/,qr/\|\|/,qr/\+/,qr/-/,qr/\//,qr/\*/];

sub parse;

while(<>){
        my $tree = parse($precedence,$_);
        print Dumper($tree);
}

sub parse{

        my ($regex,$input)=@_;
        my ($node,$before,$op,$after);
        $input=~s/\s//g;
        for(@$regex){
                $input=~m/(.+)($_)(.+)/;
                if($3){
                        ($before,$op,$after)=($1,$2,$3);
                        last;
                }
        }
        return $input if !defined($after);

        $node->{$op}=[parse($regex,$before),parse($regex,$after)];
        return $node;
}
[download]

input

5+4*3&&COND||COND2||COND3&&ANOTHER
[download]

output

{
  '&&' => [
            {
              '&&' => [
                        {
                          '+' => [
                                   '5',
                                   {
                                     '*' => [
                                              '4',
                                              '3'
                                            ]
                                   }
                                 ]
                        },
                        {
                          '||' => [
                                    {
                                      '||' => [
                                                'COND',
                                                'COND2'
                                              ]
                                    },
                                    'COND3'
                                  ]
                        }
                      ]
            },
            'ANOTHER'
          ]
}
[download]

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