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Talk:Parsing/RPN to infix conversion: Difference between revisions
Talk:Parsing/RPN to infix conversion (view source)
Revision as of 05:49, 17 December 2011
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== Examples Incorrect ==
Several examples (i.e. Python, and TCL) don't deal with associativity correctly - the code doesn't even refer to the attribute - it's defined and not used. I'm not sure of the Ruby code. The following "1 2 + 3 4 + ^ 5 6 + ^" should produce "( ( 1 + 2 ) ^ ( 3 + 4 ) ) ^ ( 5 + 6 )". --[[User:Dgamey|Dgamey]] 04:03, 17 December 2011 (UTC)
: It's actually a matter of precedence rather than associativity. RPN per se doesn't need to worry about if an op is left or right associated, but for infix notation brackets are needed for ops at same precedence level. To wit: <code>1 2 3 + -</code> is <code>1 - (2 + 3)</code>, not the same as <code>1 - 2 + 3</code>. Generally the easiest way is wrap the expression with parens whenever you pop a binary op off the stack, which will be unsightly, but correct: <code>1 2 3 4 5 + + + +</code> becomes <code>(1 + (2 + (3 + (4 + 5))))</code> --[[User:Ledrug|Ledrug]] 05:49, 17 December 2011 (UTC)
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