Better parse tree example

examples/parsetree.jade

@@ -1,5 +1,8 @@
 :conditionals
   if role == 'admin'
-    p User #{name} is an administrator
+    if name == 'tj'
+      p User is a wicked cool administrator
+    else
+      p User #{name} is an administrator
   else
     p User #{name} is a guest

examples/parsetree.js

@@ -5,6 +5,7 @@
  */
 
 var jade = require('./../lib/jade'),
+    Compiler = jade.Compiler,
     nodes = jade.nodes;
 
 var options = {
@@ -20,26 +21,39 @@ jade.renderFile(__dirname + '/parsetree.jade', options, function(err, html){
     console.log(html);
 });
 
-// To support nesting etc you will need to create a more
-// robust compiler, view ./lib/compiler.js for the core example.
+jade.filters.conditionals = function(block, compiler){
+    return new Visitor(block).compile();
+};
 
-// Without our filter we could either construct an entirely new string,
-// and simply return it (using "buf.push('buffered text')") etc, or utilize
-// the core compiler which is passed
+function Visitor(node) {
+    this.node = node;
+}
 
-jade.filters.conditionals = function(block, compiler){
-    block.nodes.forEach(function(node, i){
-        switch (node.name) {
-            case 'if':
-                block.nodes[i] = new nodes.Code('if (' + node.block.nodes[0].lines[0] + ')');
-                node.block.nodes.shift();
-                block.nodes[i].block = node.block;
-                break;
-            case 'else':
-                block.nodes[i] = new nodes.Code('else');
-                block.nodes[i].block = node.block;
-                break;
-        }
-    });
-    compiler.visit(block);
-};
+Visitor.prototype.__proto__ = Compiler.prototype;
+
+Visitor.prototype.visit = function(node){
+    if (node.name != 'else') this.line(node);
+    this.visitNode(node);
+};
+
+Visitor.prototype.visitTag = function(node){
+    switch (node.name) {
+        case 'if':
+            var condition = node.block.nodes[0].lines[0],
+                block = node.block;
+            block.nodes.shift();
+            node = new nodes.Code('if (' + condition + ')', false);
+            node.block = block;
+            this.visit(node);
+            break;
+        case 'else':
+            var block = node.block;
+            node = new nodes.Code('else', false);
+            node.block = block;
+            node.instrumentLineNumber = false;
+            this.visit(node);
+            break;
+        default:
+            Compiler.prototype.visitTag.call(this, node);
+    }
+};

lib/compiler.js

@@ -74,6 +74,7 @@ Compiler.prototype = {
      */
 
     line: function(node){
+        if (node.instrumentLineNumber === false) return;
         this.buf.push('_.lineno = ' + node.line + ';');
     },
 
@@ -85,11 +86,19 @@ Compiler.prototype = {
      */
 
     visit: function(node){
-        var name = node.constructor.name;
-        if (name != 'Code' || !node.val.match(/^ *else/)) {
-            this.line(node);
-        }
-        return this['visit' + name](node);
+        this.line(node);
+        return this.visitNode(node);
+    },
+
+    /**
+     * Visit `node`.
+     *
+     * @param {Node} node
+     * @api private
+     */
+
+    visitNode: function(node){
+        return this['visit' + node.constructor.name](node);
     },
 
     /**
@@ -228,9 +237,9 @@ Compiler.prototype = {
             this.buf.push(code.val);
         }
         if (code.block) {
-            this.buf.push('(function(){');
+            this.buf.push('  (function(){');
             this.visit(code.block);
-            this.buf.push('}).call(this);');
+            this.buf.push('  }).call(this);');
         }
     },
 

lib/nodes/code.js

@@ -6,6 +6,7 @@ var Code = module.exports = function Code(val, buffer, escape) {
     this.val = val;
     this.buffer = buffer;
     this.escape = escape;
+    if (/^ *else/.test(val)) this.instrumentLineNumber = false;
 };
 
 Code.prototype.__proto__ = Node.prototype;

test/jade.test.js

@@ -594,6 +594,22 @@ module.exports = {
             '<p class="noFoo">no foo</p>'
         ].join('');
 
+        assert.equal(html, render(str));
+
+        var str = [
+            '- var foo;',
+            '- if (foo)',
+            '  p.hasFoo= foo',
+            '- else if (true)',
+            '  p kinda foo',
+            '- else',
+            '  p.noFoo no foo'
+        ].join('\n');
+
+        var html = [
+            '<p>kinda foo</p>'
+        ].join('');
+
         assert.equal(html, render(str));
 
         var str = [