Expression evaluater

LICENSE

Copyright (c) 2015 Jack Dalton



Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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math.js

function evalMath(expr) { // evaluates an addition / subtraction expression
    expr = expr.replace(/-/g, "+-"); // we don't subtract, we just add negative numbers (3-2 -> 3+(-2))
    expr = expr.replace(/[a-zA-Z\ ]/g, ""); // strips crap (non numbers)
    var terms = expr.split(/\+/g); // splits into terms (3+2-1 -> [3, 2, -1])
    var sum = 0;
    for (var i = 0; i < terms.length; i++) { // iterate through our terms
        sum += Number(terms[i]); // add term to sum (Note that we don't need to parse anything as a number until now)
    }
    return sum; // returns our calculated sum!
}