Postfix traversal to generate code

Let us use our running logical expression example to do a traversal through the tree to generate a code list. The actions are similar to that of a postfix traversal though the tree.

( X & Y ) | ( ( ! X ) & ( ! Y ) )

Here is the JavaScript code.

var treeList1 = [
	"op2",
	"or",
	[
		"op2",
		"and",
		["var", "x"],
		["var", "y"],
		],
	[
		"op2",
		"and",
		[
			"op1",
			"not",
			["var", "x"],
			],
		[
			"op1",
			"not",
			["var", "y"],
			],
		]
	];

function generate(tree1) {
	var type1 = tree1[0];
	if (type1 == "op1") {
		var op1 = tree1[1];
		var right1 = tree1[2];
		generate(right1);
		codeList1.push([type1,op1]);
		}
	else if (type1 == "op2") {
		var op2 = tree1[1];
		var left1 = tree1[2];
		var right1 = tree1[3];
		generate(left1);
		generate(right1);
		codeList1.push([type1,op2]);
		}
	else if (type1 == "var") {
		var name1 = tree1[1];
		codeList1.push([type1,name1]);
		}
	else if (type1 == "int") {
		var value1 = tree1[1];
		codeList1.push([type1,value1]);
		}
	}
var codeList1 = [];
generate(treeList1);

var n1 = codeList1.length;
for (i1=0; i1 <= n1-1; i1++) {
	var code1 = codeList1[i1];
	var type1 = code1[0];
	var value1 = code1[1];
	console.log(i1+". [\""+type1+"\",\""+value1+"\"]\n");
	}

Here is the output of the JavaScript code.

0. ["var","x"]

1. ["var","y"]

2. ["op2","and"]

3. ["var","x"]

4. ["op1","not"]

5. ["var","y"]

6. ["op1","not"]

7. ["op2","and"]

8. ["op2","or"]