postfix_evaluator.js
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var Mexp=require('./postfix.js');
Mexp.prototype.postfixEval = function (UserDefined) {
'use strict';
UserDefined=UserDefined||{};
UserDefined.PI=Math.PI;
UserDefined.E=Math.E;
var stack=[],pop1,pop2,pop3;
var disp=[];
var temp='';
var arr=this.value;
var bool=(typeof UserDefined.n!=="undefined");
for(var i=0;i<arr.length;i++){
if(arr[i].type===1){
stack.push({value:arr[i].value,type:1});
}
else if(arr[i].type===3){
stack.push({value:UserDefined[arr[i].value],type:1});
}
else if(arr[i].type===0){
if(typeof stack[stack.length-1].type==="undefined"){
stack[stack.length-1].value.push(arr[i]);
}
else stack[stack.length-1].value=arr[i].value(stack[stack.length-1].value);
}
else if(arr[i].type===7){
if(typeof stack[stack.length-1].type==="undefined"){
stack[stack.length-1].value.push(arr[i]);
}
else stack[stack.length-1].value=arr[i].value(stack[stack.length-1].value);
}
else if(arr[i].type===8){
pop1=stack.pop();
pop2=stack.pop();
stack.push({type:1,value:arr[i].value(pop2.value,pop1.value)});
}
else if(arr[i].type===10){
pop1=stack.pop();
pop2=stack.pop();
if(typeof pop2.type==="undefined"){
pop2.value=pop2.concat(pop1);
pop2.value.push(arr[i]);
stack.push(pop2);
}
else if (typeof pop1.type==="undefined") {
pop1.unshift(pop2);
pop1.push(arr[i]);
stack.push(pop1);
}
else{
stack.push({type:1,value:arr[i].value(pop2.value,pop1.value)});
}
}
else if(arr[i].type===2||arr[i].type===9){
pop1=stack.pop();
pop2=stack.pop();
if(typeof pop2.type==="undefined"){
console.log(pop2);
pop2=pop2.concat(pop1);
pop2.push(arr[i]);
stack.push(pop2);
}
else if (typeof pop1.type==="undefined") {
pop1.unshift(pop2);
pop1.push(arr[i]);
stack.push(pop1);
}
else{
stack.push({type:1,value:arr[i].value(pop2.value,pop1.value)});
}
}
else if(arr[i].type===12){
pop1=stack.pop();
if (typeof pop1.type!=="undefined") {
pop1=[pop1];
}
pop2=stack.pop();
pop3=stack.pop();
stack.push({type:1,value:arr[i].value(pop3.value,pop2.value,new Mexp(pop1))});
}
else if(arr[i].type===13){
if(bool){
stack.push({value:UserDefined[arr[i].value],type:3});
}
else stack.push([arr[i]]);
}
}
if (stack.length>1) {
throw(new Mexp.exception("Uncaught Syntax error"));
}
return stack[0].value>1000000000000000?"Infinity":parseFloat(stack[0].value.toFixed(15));
};
Mexp.eval=function(str,tokens,obj){
if (typeof tokens==="undefined") {
return this.lex(str).toPostfix().postfixEval();
}
else if (typeof obj==="undefined") {
if (typeof tokens.length!=="undefined")
return this.lex(str,tokens).toPostfix().postfixEval();
else
return this.lex(str).toPostfix().postfixEval(tokens);
}
else
return this.lex(str,tokens).toPostfix().postfixEval(obj);
};
module.exports=Mexp;