From 98f43889c427cda5668ab2ca7d61df16914c77b8 Mon Sep 17 00:00:00 2001
From: David Greenspan <dgreenspan@alum.mit.edu>
Date: Thu, 25 Jul 2013 07:57:26 -0700
Subject: [PATCH] basic fields, `set`, event.component

---
 packages/ui/fields.js   |  8 ++++++++
 packages/ui/template.js | 24 +++++++++++++++++++++---
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/packages/ui/fields.js b/packages/ui/fields.js
index 9a6a2606e1..5271133463 100644
--- a/packages/ui/fields.js
+++ b/packages/ui/fields.js
@@ -72,6 +72,14 @@ _extend(UI.Component, {
   lookup: function (id) {
     return this.get(id, true);
   },
+  set: function (id, value) {
+    var comp = findComponentWithProp(id, this);
+    if (! comp || ! comp[id])
+      throw new Error("Can't find field: " + id);
+    if (! comp[id].$set)
+      throw new Error("Not a settable field: " + id);
+    comp[id].$set(value);
+  },
   // convenient syntax
   withData: function (data) {
     return this.extend({data: data});
diff --git a/packages/ui/template.js b/packages/ui/template.js
index a58d7bbe43..61436e45b0 100644
--- a/packages/ui/template.js
+++ b/packages/ui/template.js
@@ -27,7 +27,24 @@ UI.makeTemplate = function (underlying) {
         var oldProp = underlying[k];
         var givenProp = options[k];
 
-        if (k.indexOf(' ') >= 0) {
+        if (k === 'fields') {
+          // XXX basic fields impl
+          // XXX could support functions as initial field values
+          _.each(givenProp, function (fieldValue, fieldName) {
+            var getter = function () {
+              getter.$dep.depend();
+              return getter.$value;
+            };
+            getter.$value = fieldValue; // initial value
+            getter.$dep = new Deps.Dependency;
+            getter.$set = function (v) {
+              getter.$value = v;
+              getter.$dep.changed();
+            };
+            underlying[fieldName] = getter;
+          });
+
+        } else if (k.indexOf(' ') >= 0) {
           // event handler
           // XXX clean up
           var eventType = k.slice(0, k.indexOf(' '));
@@ -40,8 +57,9 @@ UI.makeTemplate = function (underlying) {
             handler: (function (handler) {
               return function (evt) {
                 // XXX
-                var data = UI.body.findByElement(
-                  evt.currentTarget).get();
+                var comp = UI.body.findByElement(evt.target);
+                evt.component = comp;
+                var data = comp.get();
                 handler.call(data, evt);
               };
             })(givenProp)