postfix with functions

Author: dominhhai

app.js

@@ -3,6 +3,7 @@ const calc = require('./calc')
 
 module.exports = function app (exp) {
   var type = postfixer.getExpressionType(exp)
+  console.log(type)
   var rst = null
   if (type === postfixer.PREFIX) {
     rst = calcPrefix(exp)
@@ -58,6 +59,16 @@ function calcPostfix (exp) {
         var o1 = getValue(stack.pop())
         var rst = calc(token, o1, o2)
         stack.push(rst)
+      } else if (token[token.length - 1] === '(') {
+        var args = []
+        var o = stack.pop()
+        while (o !== ')') {
+          args.push(o)
+          o = stack.pop()
+        }
+        args.reverse()
+        var rst = Math[token.substr(0, token.length - 1)].apply(null, args)
+        stack.push(rst)
       } else {
         stack.push(token)
       }

postfixer.js

@@ -17,7 +17,7 @@ const MATH_EXTEND = {
 const isOperator = require('./calc').isOperator
 
 function getExpressionType (exp) {
-  if (isOperator(exp[exp.length - 1])) return POSTFIX
+  if (isOperator(exp[exp.length - 1]) || exp[exp.length - 1] === '(') return POSTFIX
   if (isOperator(exp[0])) {
     // negative number -> infix notation
     if (exp.length > 1 && exp[1] >= '0' && exp[1] <= '9') return INFIX

test/z.js

@@ -0,0 +1,16 @@
+const test = require('tape')
+var app = require('../app')
+
+test('func - postfix test', function (t) {
+  t.equal(app('1 3 +'), 4)
+
+  t.equal(app(') 3 0 -2 19 min('), 4)
+
+  t.equal(app(') 3 0 -2 19 max('), 4)
+
+  t.equal(app(') -1 abs( 10 +'), 4)
+
+  t.equal(app(') 2 ) 2 3 pow( - max('), 4)
+
+  t.end()
+})