From 26105034da4fcce7ac883c899d781f016559310d Mon Sep 17 00:00:00 2001
From: ruki <waruqi@gmail.com>
Date: Thu, 8 Nov 2018 00:38:48 +0800
Subject: switch to vuepress

---
 .../math-expression-evaluator/src/postfix.js       | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100755 node_modules/math-expression-evaluator/src/postfix.js

(limited to 'node_modules/math-expression-evaluator/src/postfix.js')

diff --git a/node_modules/math-expression-evaluator/src/postfix.js b/node_modules/math-expression-evaluator/src/postfix.js
new file mode 100755
index 00000000..9c8dd424
--- /dev/null
+++ b/node_modules/math-expression-evaluator/src/postfix.js
@@ -0,0 +1,50 @@
+
+    var Mexp=require('./lexer.js');
+
+	Mexp.prototype.toPostfix = function () {
+		'use strict';
+		var post=[],elem,popped,prep,pre,ele;
+    	var stack=[{value:"(",type:4,pre:0}];
+		var arr=this.value;
+		for (var i=1; i < arr.length; i++) {
+			if(arr[i].type===1||arr[i].type===3||arr[i].type===13){	//if token is number,constant,or n(which is also a special constant in our case)
+				if(arr[i].type===1)
+					arr[i].value=Number(arr[i].value);
+				post.push(arr[i]);
+			}
+			else if(arr[i].type===4){
+				stack.push(arr[i]);
+			}
+			else if(arr[i].type===5){
+				while((popped=stack.pop()).type!==4){
+					post.push(popped);
+				}
+			}
+			else if(arr[i].type===11){
+				while((popped=stack.pop()).type!==4){
+					post.push(popped);
+				}
+				stack.push(popped);
+			}
+			else {
+				elem=arr[i];
+				pre=elem.pre;
+				ele=stack[stack.length-1];
+				prep=ele.pre;
+				var flag=ele.value=='Math.pow'&&elem.value=='Math.pow';
+				if(pre>prep)stack.push(elem);
+				else {
+					while(prep>=pre&&!flag||flag&&pre<prep){
+						popped=stack.pop();
+						ele=stack[stack.length-1];
+						post.push(popped);
+						prep=ele.pre;
+						flag=elem.value=='Math.pow'&&ele.value=='Math.pow';
+					}
+					stack.push(elem);
+				}
+			}
+		}
+		return new Mexp(post);
+	};
+    module.exports=Mexp;
\ No newline at end of file
-- 
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