Well, you can do this, but it is a sort of silly thing to do. A better solution would be to put the time in to actually evaluate the user's input and act on that. If you really want to build a calculator, I'd suggest using reverse polish notation on your first go (see dc(1)) because it is easier to parse (less ambiguous) than standard notation. Now for the silly way (which is worth seeing since evaluating strings as code is sometimes useful): 
#!/usr/bin/perl -w
use strict;

my $eq = <STDIN>;
print eval $eq, "\n";

[download]
This will do what you want, but it is very DANGEROUS because any arbitrary code can be embedded in the expression (although this isn't exactly a production project anyway). If you wanted to go to the trouble to catch non-calc-related code, you might as well code up a real calculator. If not, call perl -e and do a calulation on the command line.

In reply to Re: Inputing an Operator is it possible? by dbp
in thread Inputing an Operator is it possible? by $Variable_B

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