calculate.pl dialog

$ ./calculate.pl
EQUALS
 (undefined)
OK
CLEAR
OK
EQUALS

 = 0
OK
PLUS 42
OK
EQUALS
 = 42
OK
OVER 7
OK
TIMES 3
OK
MINUS 3

OK
EQUALS
 = 15
OK
explode
Invalid statement

##</code><code>##

$ ./calculate.pl
> EQUALS
 (undefined)
OK
> CLEAR

OK
> EQUALS
 = 0
OK 
> PLUS 42
OK
> EQUALS
 = 42
OK
> OVER 7

OK
> TIMES 3
OK
> MINUS 3
OK
> EQUALS
 = 15
OK
> explode

Invalid statement
>

##</code><code>##

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

my $total;
print "> ";
while(my $line = <>){
  chomp $line;
  my ($cmd, $num) = split " ", $line, 2;
  process($cmd,$num,$total);
  print "OK\n\>";
}

sub process{
  my($cmd,$num,$total) = @_;
  print "COMMAND: $cmd, VALUE: $num, TOTAL: $total \n";
}