Merge pull request #154 from mikeric/view-context-updating

View context updating

@@ -14,7 +14,7 @@ class Rivets.Binding
   # All information about the binding is passed into the constructor; the
   # containing view, the DOM node, the type of binding, the model object and the
   # keypath at which to listen for changes.
-  constructor: (@view, @el, @type, @model, @keypath, @options = {}) ->
+  constructor: (@view, @el, @type, @key, @keypath, @options = {}) ->
     unless @binder = @view.binders[type]
       for identifier, value of @view.binders
         if identifier isnt '*' and identifier.indexOf('*') isnt -1
@@ -25,11 +25,9 @@ class Rivets.Binding
             @args.shift()
 
     @binder or= @view.binders['*']
-
-    if @binder instanceof Function
-      @binder = {routine: @binder}
-
+    @binder = {routine: @binder} if @binder instanceof Function
     @formatters = @options.formatters || []
+    @model = @view.models[@key]
 
   # Applies all the current formatters to the supplied value and returns the
   # formatted value.
@@ -125,6 +123,13 @@ class Rivets.Binding
 
         @view.config.adapter.unsubscribe model, keypath, @sync
 
+  # Updates the binding's model from what is currently set on the view. Unbinds
+  # the old model first and then re-binds with the new model.
+  update: =>
+    @unbind()
+    @model = @view.models[@key]
+    @bind()
+
 # A collection of bindings built from a set of parent elements.
 class Rivets.View
   # The DOM elements and the model objects for binding are passed into the
@@ -182,17 +187,17 @@ class Rivets.View
             options.formatters = pipes
             options.bypass = path.indexOf(':') != -1
             if splitPath[0]
-              model = @models[splitPath.shift()]
+              key = splitPath.shift()
             else
-              model = @models
+              key = null
               splitPath.shift()
             keypath = splitPath.join '.'
 
-            if model
+            if @models[key]?
               if dependencies = context.shift()
                 options.dependencies = dependencies.split /\s+/
 
-              @bindings.push new Rivets.Binding @, node, type, model, keypath, options
+              @bindings.push new Rivets.Binding @, node, type, key, keypath, options
 
         attributes = null if attributes
 
@@ -224,6 +229,12 @@ class Rivets.View
   publish: =>
     binding.publish() for binding in @select (b) -> b.binder.publishes
 
+  # Updates the view's models along with any affected bindings.
+  update: (models = {}) =>
+    for key, model of models
+      @models[key] = model
+      binding.update() for binding in @select (b) -> b.key is key
+
 # Cross-browser event binding.
 bindEvent = (el, event, handler, context) ->
   fn = (e) -> handler.call context, e