Update README.md

README.md

@@ -7,20 +7,24 @@ variables.
 
 ActionScript 3:
 
-			var expectedResult:Number = a + 2 - (+3 * (+b - -c) * 2 * (Math.max(2, 1))) - Math.min(1, d_e)
-			var exp:String =           'a + 2 - (+3 * (+b - -c) * 2 * (     max(2, 1))) -      min(1, d_e)'
-
-			var tree:ASTree = ASTreeParser.parse(exp)
-			tree.setVariable('a', a)
-			tree.setVariable('b', b)
-			tree.setVariable('c', c)
-			tree.setVariable('d_e', d_e)
-			tree.setFunction('min', Math.min) // min() is built-in
-			actually, as well as max().
-			var actualResult:Number = tree.calculate()
-
-			trace(tree.toStringWithVariablesReplaced(), '=', actualResult)
-			Utils.assert(expectedResult == actualResult)
+	var expectedResult:Number = a + 2 - (+3 * (+b - -c) * 2 * (Math.max(2, 1))) - Math.min(1, d_e)
+	var exp:String =           'a + 2 - (+3 * (+b - -c) * 2 * (     max(2, 1))) -      min(1, d_e)'
+
+	// Step 1: Parse expression string.
+	var tree:ASTree = ASTreeParser.parse(exp)
+
+	// Step 2: Set variables and functions
+	tree.setVariable('a', a)
+	tree.setVariable('b', b)
+	tree.setVariable('c', c)
+	tree.setVariable('d_e', d_e)
+	tree.setFunction('min', Math.min) // min() is built-in actually, as well as max().
+
+	// Step 3: Get the result. Step 2, 3 could be done repeatly.
+	var actualResult:Number = tree.calculate()
+
+	trace(tree.toStringWithVariablesReplaced(), '=', actualResult)
+	Utils.assert(expectedResult == actualResult)
 
 
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