Perl calculator

See how Perl can handle a calculator program efficiently

#!/usr/bin/perl
# Simple Perl Calculator
use strict;
use warnings;

sub calculator {
    print("Perl Calculator\n");
    print("Type a formula (e.g., 12+34*2) and press Enter. Type 'exit' to quit.\n");

    while (1) {
        print("Enter formula: ");
        my $input = <STDIN>;
        chomp($input);

        last if $input =~ /^exit$/i;

        # Allow only numbers, spaces, and arithmetic operators
        if ($input =~ /^[\d\s\+\-\*\/\(\)\.]+$/) {
            my $result = eval $input;
            if ($@) {
                print "Error in formula: $@\n";
            } else {
                print "Result: $result\n";
            }
        } else {
            print "Invalid input. Only numbers and + - * / ( ) are allowed.\n";
        }
    }
}

calculator();