Equation (expression) parser with precedence?

Question

I\'ve developed an equation parser using a simple stack algorithm that will handle binary (+, -, |, &, *, /, etc) operators, unary (!) operators, and parenthesis.

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Answer 1

A Python solution using pyparsing can be found here. Parsing infix notation with various operators with precedence is fairly common, and so pyparsing also includes the infixNotation (formerly operatorPrecedence) expression builder. With it you can easily define boolean expressions using "AND", "OR", "NOT", for example. Or you can expand your four-function arithmetic to use other operators, such as ! for factorial, or '%' for modulus, or add P and C operators to compute permutations and combinations. You could write an infix parser for matrix notation, that includes handling of '-1' or 'T' operators (for inversion and transpose). The operatorPrecedence example of a 4-function parser (with '!' thrown in for fun) is here and a more fully featured parser and evaluator is here.