# Math Processor //JavaScript Repository

## Description

Mathematical expression parser using reverse polish notation and binary tree.
Created: 2005.10.07

``````//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/classes/math-processor [rev. #1]

MathProcessor = function(){
var o = this;
o.o = {
"+": function(a, b){ return +a + b; },
"-": function(a, b){ return a - b; },
"%": function(a, b){ return a % b; },
"/": function(a, b){ return a / b; },
"*": function(a, b){ return a * b; },
"^": function(a, b){ return Math.pow(a, b); },
"~": function(a, b){ return Math.sqrt(a, b); }
};
o.s = { "^": 3, "~": 3, "*": 2, "/": 2, "%": 1, "+": 0, "-": 0 };
o.u = {"+": 1, "-": -1}, o.p = {"(": 1, ")": -1};
};
with({p: MathProcessor.prototype}){
p.methods = {
div: function(a, b){ return parseInt(a / b); },
fra: function(a){ return a - parseInt(a); },
sum: function(n1, n2, n3, n){ for(var r = 0, a, l = (a = arguments).length; l; r += a[--l]); return r; },
medium: function(n1, n2, n3, n){ for(var r = 0, a, l = (a = arguments).length; l; r += a[--l]); return r / a.length; }
};
p.parse = function(e){
for(var n, x, _ = this, o = [], s = [x = _.RPN(e.replace(/ /g, "").split(""))]; s.length;)
for((n = s[s.length-1], --s.length); n[2]; o[o.length] = n, s[s.length] = n[3], n = n[2]);
for(; (n = o.pop()) != undefined; n[0] = _.o[n[0]](isNaN(n[2][0]) ? _.f(n[2][0]) : n[2][0], isNaN(n[3][0]) ? _.f(n[3][0]) : n[3][0]));
return +x[0];
};
p.RPN = function(e){
var x, r, _ = this, c = r = [, , , 0];
if(e[0] in _.u || !e.unshift("+"))
for(; e[1] in _.u; e[0] = _.u[e.shift()] * _.u[e[0]] + 1 ? "+" : "-");
(c[3] = [_.u[e.shift()], c, , 0])[1][0] = "*", (r = [, , c, 0])[2][1] = r;
(c[2] = _.v(e))[1] = c;
(!e.length && (r = c)) || (e[0] in _.s && ((c = r)[0] = e.shift(), !e.length && _.error()));
while(e.length){
if(e[0] in _.u){
for(; e[1] in _.u; e[0] = _.u[e.shift()] * _.u[e[0]] + 1 ? "+" : "-");
(c = c[3] = ["*", c, , 0])[2] = [-1, c, , 0];
}
(c[3] = _.v(e))[1] = c;
e[0] in _.s && (c = _.s[e[0]] > _.s[c[0]] ?
((c[3] = (x = c[3], c[2]))[1][2] = [e.shift(), c, x, 0])[2][1] = c[2]
: r == c ? (r = [e.shift(), , c, 0])[2][1] = r
: ((r[2] = (x = r[2], [e.shift(), r, ,0]))[2] = x)[1] = r[2]);
}
return r;
};
p.v = function(e){
var i, j, l, _ = this;
if("0123456789.".indexOf(e[0]) + 1){
for(i = -1, l = e.length; ++i < l && "0123456789.".indexOf(e[i]) + 1;);
return [+e.splice(0,i).join(""), , , 0];
}
else if(e[0] == "("){
for(i = 0, l = e.length, j = 1; ++i < l && (e[i] in _.p && (j += _.p[e[i]]), j););
return _.RPN(l = e.splice(0,i), l.shift(), !j && e.shift());
}
else{
if(((j = e[0].toLowerCase()) >= "a" && j <= "z") || j == "_"){
for(i = 0; ((j = e[++i].toLowerCase()) >= "a" && j <= "z") || j == "_" || (j >= 0 && j <= 9););
if(j == "("){
for(var l = e.length, j = 1; ++i < l && (e[i] in _.p && (j += _.p[e[i]]), j););
return [e.splice(0,i+1).join(""), , , 0];
}
}
}
_.error();
};
p.f = function(e){
var n, i = 0, _ = this;
if(((e = e.split(""))[i] >= "a" && e[i] <= "z") || e[i] == "_"){
while((e[++i] >= "a" && e[i] <= "z") || e[i] == "_" || (e[i] >= 0 && e[i] <= 9));
if(e[i] == "("){
!_.methods[n = e.splice(0, i).join("")] && _.error("Fun??o \"" + n + "\" n?o encontrada"), e.shift();
for(var a = [], i = -1, j = 1; e[++i] && (e[i] in _.p && (j += _.p[e[i]]), j);)
j == 1 && e[i] == "," && (a.push(_.parse(e.splice(0, i).join(""))), e.shift(), i = -1);
a.push(_.parse(e.splice(0,i).join(""))), !j && e.shift();
}
return _.methods[n].apply(_, a);
}
};
p.error = function(s){
throw new Error("MathProcessor: " + (s || "Erro na express?o"));
};
}``````

## Example (Example)

``````<form id="math" action="#">
<fieldset>
<legend>MathProcessor</legend>
<label>Express?o</label><input type="text" name="exp" value="(medium(sum(1, 0, 1), 1) + .5) / 2 * 2 + 1" /><br /><br />
<input type="submit" value="MathProcessor.parse()" />
</fieldset>
</form>

<script type="text/javascript">
//<![CDATA[

var p = new MathProcessor(), f = document.forms.math;

e.preventDefault();
try{
}catch(e){
}
});

//]]>
</script>``````

## Help

#### Constructor

MathProcessor(void)
Generates an instance of MathProcessor.

#### Properties

MathProcessor.methods: Array
It's an associative array that allows users to increase the parser by adding your own functions.

#### Methods

MathProcessor.parse(expression: String): Number
Parses a set of pre-defined commands to make a mathematical expression.
expression
mathematical expression that will be parsed

#### Basic operations

( and )
Precedence operator
+
-
Subtraction
*
Multiplication
/
Division
^
Power
~
Square Root
%
Division Reminder