Refactoring how _position is called to be promise-based

The render method now returns a promise. Once this promise is resolved,
the _position method for that node will be called (if applicable). This
promise must be resolved only after all subordinate nodes have completed
their render phase (the promise returned by subordinate node's render
method has resolved). Node that do not have subordinates can return the
result of calling terminalRender, and proxied renders only need to
return the result of calling proxy.

With this change, it is no longer necessary to explicitly position
subordinate nodes. They will already be positioned once their render
promise is resolved.

src/js/parser/javascript/any_character.js

@@ -6,5 +6,6 @@ export default _.extend({}, Base, {
 
   _render() {
     this.renderLabel('any character');
+    return this.terminalRender();
   }
 });

src/js/parser/javascript/base.js

@@ -1,4 +1,5 @@
 import _ from 'lodash';
+import Q from 'q';
 
 export default {
   setContainer(container) {
@@ -50,37 +51,43 @@ export default {
     }
 
     this._labelGroups = [];
-    this._render();
-  },
-
-  position() {
-    if (this._proxy) {
-      this._proxy.position();
-    } else {
+    return this._render().then((function() {
+      if (!this._proxy) {
         _.each(this._labelGroups, this.positionLabel.bind(this));
         this._position();
       }
+
+      return this;
+    }).bind(this));
   },
 
   proxy(node) {
     this._proxy = node;
-    this._proxy.render(this.container);
+    return this._proxy.render(this.container);
+  },
+
+  terminalRender() {
+    var deferred = Q.defer();
+
+    setTimeout(() => { deferred.resolve() });
+    return deferred.promise;
   },
 
   _render() {
-    console.log(this);
+    console.log(this.type, this);
 
     this.container.addClass('placeholder');
 
-    this.renderLabel(this.textValue)
+    this.renderLabel(this.type + ': ' + this.textValue)
       .select('rect').attr({
         rx: 10,
         ry: 10
       });
+
+    return this.terminalRender();
   },
 
-  _position() {
-  },
+  _position() {},
 
   spaceHorizontally(items, options) {
     var verticalCenter = 0;

src/js/parser/javascript/charset.js

@@ -1,4 +1,5 @@
 import _ from 'lodash';
+import Q from 'q';
 import Base from './base.js';
 
 export default _.extend({}, Base, {
@@ -9,14 +10,12 @@ export default _.extend({}, Base, {
 
     this.partContainer = this.container.group();
 
-    _.each(this.parts.elements, (part => {
-      part.render(this.partContainer.group());
-    }).bind(this));
+    return Q.all(_.map(this.parts.elements, (part => {
+      return part.render(this.partContainer.group());
+    }).bind(this)));
   },
 
   _position() {
-    _.invoke(this.parts.elements, 'position');
-
     this.spaceVertically(this.parts.elements, {
       padding: 5
     });

src/js/parser/javascript/charset_range.js

@@ -1,23 +1,23 @@
 import _ from 'lodash';
+import Q from 'q';
 import Base from './base.js';
 
 export default _.extend({}, Base, {
   type: 'charset-range',
 
   _render() {
-    this.first.render(this.container.group());
-    this.last.render(this.container.group());
-
     this.hyphen = this.container.text()
       .attr({
         text: '-'
       });
+
+    return Q.all([
+      this.first.render(this.container.group()),
+      this.last.render(this.container.group())
+    ]);
   },
 
   _position() {
-    this.first.position();
-    this.last.position();
-
     this.spaceHorizontally([this.first, this.hyphen, this.last], {
       padding: 5
     });

src/js/parser/javascript/escape.js

@@ -18,6 +18,8 @@ export default _.extend({}, Base, {
         rx: 3,
         ry: 3
       });
+
+    return this.terminalRender();
   },
 
   // Escape code mappings

src/js/parser/javascript/literal.js

@@ -10,5 +10,7 @@ export default _.extend({}, Base, {
         rx: 3,
         ry: 3
       });
+
+    return this.terminalRender();
   }
 });

src/js/parser/javascript/match.js

@@ -1,4 +1,5 @@
 import _ from 'lodash';
+import Q from 'q';
 import Base from './base.js';
 
 export default _.extend({}, Base, {
@@ -18,20 +19,17 @@ export default _.extend({}, Base, {
     }
 
     if (this.contents.anchor_start || this.contents.anchor_end || this.contents.parts.length !== 1) {
-      _.each(this.contents.parts, (function(part) {
-        part.render(this.container.group());
-      }).bind(this));
+      return Q.all(_.map(this.contents.parts, (function(part) {
+        return part.render(this.container.group());
+      }).bind(this)));
     } else {
-      this.proxy(this.contents.parts[0]);
+      return this.proxy(this.contents.parts[0]);
     }
   },
 
   _position() {
-    var items;
+    var items = _(this.contents).at('anchor_start', 'parts', 'anchor_end').flatten().compact().value();
 
-    _.invoke(this.contents.parts, 'position');
-
-    items = _(this.contents).at('anchor_start', 'parts', 'anchor_end').flatten().compact().value();
     this.spaceHorizontally(items, {
       padding: 10
     });

src/js/parser/javascript/match_fragment.js

@@ -6,16 +6,15 @@ export default _.extend({}, Base, {
 
   _render() {
     if (this._repeat.textValue === '') {
-      this.proxy(this._content);
+      return this.proxy(this._content);
     } else {
-      this._content.render(this.container.group());
+      return this._content.render(this.container.group());
     }
   },
 
   _position() {
     var box, paths = [];
 
-    this._content.position();
     this._content.transform(this._repeat.contentPosition());
 
     box = this._content.getBBox();

src/js/parser/javascript/regexp.js

@@ -1,4 +1,5 @@
 import _ from 'lodash';
+import Q from 'q';
 import Base from './base.js';
 
 export default _.extend({}, Base, {
@@ -8,14 +9,14 @@ export default _.extend({}, Base, {
     var matches = this.matches();
 
     if (matches.length === 1) {
-      this.proxy(matches[0]);
+      return this.proxy(matches[0]);
     } else {
       this.matchContainer = this.container.group()
         .addClass('regexp-matches');
 
-      _.each(matches, (match => {
-        match.render(this.matchContainer.group());
-      }).bind(this));
+      return Q.all(_.map(matches, (match => {
+        return match.render(this.matchContainer.group());
+      }).bind(this)));
     }
   },
 
@@ -24,8 +25,6 @@ export default _.extend({}, Base, {
         containerBox,
         paths;
 
-    _.invoke(matches, 'position');
-
     this.spaceVertically(matches, {
       padding: 5
     });

src/js/parser/javascript/root.js

@@ -5,7 +5,7 @@ export default _.extend({}, Base, {
   type: 'root',
 
   _render() {
-    this.regexp.render(this.container.group());
+    var promise = this.regexp.render(this.container.group());
     this.regexp.transform(Snap.matrix()
       .translate(10, 0));
 
@@ -15,14 +15,12 @@ export default _.extend({}, Base, {
     this.end = this.container.circle()
       .addClass('pin')
       .attr({ r: 5 });
+
+    return promise;
   },
 
   _position() {
-    var contentBox;
-
-    this.regexp.position();
-
-    contentBox = this.regexp.getBBox();
+    var contentBox = this.regexp.getBBox();
 
     this.start.transform(Snap.matrix()
       .translate(0, contentBox.cy));

src/js/parser/javascript/subexp.js

@@ -18,15 +18,13 @@ export default _.extend({}, Base, {
     if (label) {
       this.renderLabeledBox(label);
 
-      this.regexp.render(this.container.group());
+      return this.regexp.render(this.container.group());
     } else {
-      this.proxy(this.regexp);
+      return this.proxy(this.regexp);
     }
   },
 
   _position() {
-    this.regexp.position();
-
     this.positionLabeledBox(this.regexp, {
       padding: 10
     });

src/js/regexper.js

@@ -88,18 +88,11 @@ export default class Regexper {
     parser.resetGroupCounter();
 
     return Q.fcall(parser.parse.bind(parser), expression)
+      .then(null, this.showError.bind(this))
+      .invoke('render', snap.group())
       .then((result) => {
-        result.render(snap.group());
-        return result;
-      }, this.showError.bind(this))
-      .then((result) => {
-        var deferred = Q.defer();
-
-        setTimeout(() => {
         var box;
 
-          result.position();
-
         box = result.getBBox();
         result.container.transform(Snap.matrix()
           .translate(padding - box.x, padding - box.y));
@@ -107,11 +100,6 @@ export default class Regexper {
           width: box.width + padding * 2,
           height: box.height + padding * 2
         });
-
-          deferred.resolve();
-        });
-
-        return deferred.promise;
       });
   }
 }