my %symtab;

while (<FILE>) {
   chomp;
   if (/^(\w+)\|(\d+)$/) {
      $symtab{$1} = $2;
   } else {
      # Error
   }
}

print($symtab{A} + $symtab{B}, $/);
print($symtab{A} + $symtab{B} + $symtab{C}, $/);
print($symtab{C} + $symtab{A} + $symtab{D}, $/);
[download]

Like this, or do you need to parse the equations too? Update: Here's a version that parses sums too:

my %symtab;

while (<DATA>) {
   chomp;
   if (/^(\w+)\|(\d+)$/) {
      $symtab{$1} = $2;
   } else {
      # Error
   }
}

foreach (
   'A+B',
   'A+B+C',
   'C+A+D',
) {
   my $sum = 0;

   foreach (split(/\+/, $_)) {
      my $ident = $_;
      $ident =~ s/^\s+//;
      $ident =~ s/\s+$//;
      if (exists($symtab{$ident})) {
         $sum += $symtab{$ident};
      } else {
         # Error
      }
   }

   print("$_=$sum$/");
}

__DATA__
A|10
B|20
C|20
D|40
[download]

Probably it is better to simply use split, so that you don't need to worry about things like the format of the number.

use strict;
use warnings;

my ($A, $B, $C, $D);
while (<DATA>) {
    chomp;
    my @parts = split /\|/;
    print "\$$parts[0] = $parts[1]\n";
    eval("\$$parts[0] = $parts[1]");
}
print "$A\n";
print "$B\n";
print "$C\n";
print "$D\n";

__DATA__
A|-10
B|20_000
C|20.1234
D|2E-3
[download]

Then you can do whatever you want with those variables.

If he wants a more flexible number format than \d+, one of the perlfaqs gives a regexp that matches what Perl considers a number.

Your code handles A|system("rm -rf /") quite interestingly. If you call that a feature (plausible), then A|$B||$C is buggy. Using split(/\|/, $_, 2) instead of the current split solves it.

Your code also handles A = system("rm -rf /")|0 quite interestingly, and I can't see that being called a feature.

one of the perlfaqs gives a regexp that matches what Perl considers a number

That would be perldoc -q whole, also available online.

File B:
Group Name: Small
Junk: lll
Product Name:
AAA
BBB
Group Name: Big
Junk: ggg
Product Name:
AAA
CCC
DDD
more<bg> I need to print out:<br Group Small:
AAA 10
BBB 20
Total 20
Group Big:
AAA 10
CCC 30
DDD 40
Total 80 Thanks!