Code golf: Reverse Polish notation (postfix) evaluator

Posted by Dario on Stack Overflow See other posts from Stack Overflow or by Dario
Published on 2009-10-08T16:31:30Z Indexed on 2010/06/06 20:32 UTC
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After having had code-golf contests on ordinary mathematical expressions, I just thought it would also be quite interesting how short an evaluation function for postfix notation (RPN) can be.

Examples for RPN:

1 2 + == 3
1 2 + 3 * == 9
0 1 2 3 + + - 2 6 * + 3 / 1 - == 1
3 2 / 2.0 + == 3.5

To make things shorter, only +, -, * and /, all just in their binary version, must be supported. Operators/Operands are delimited by one space, divsions by zero don't have to be handled.

The resulting code should be a function that takes the postfix string as input and returns the resulting number.

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