implem-nested-prop.patch

diff --git a/kivy/lang.py b/kivy/lang.py
index 10cdd21..5fa43bc 100644
--- a/kivy/lang.py
+++ b/kivy/lang.py
@@ -613,6 +613,7 @@ class ParserRule(object):
     '''
 
     __slots__ = ('ctx', 'line', 'name', 'children', 'id', 'properties',
+            'nested_properties',
             'canvas_before', 'canvas_root', 'canvas_after',
             'handlers', 'level', 'cache_marked')
 
@@ -632,6 +633,8 @@ class ParserRule(object):
         self.id = None
         #: Properties associated to the rule
         self.properties = OrderedDict()
+        #: Nested properties
+        self.nested_properties = OrderedDict()
         #: Canvas normal
         self.canvas_root = None
         #: Canvas before
@@ -651,6 +654,8 @@ class ParserRule(object):
     def precompile(self):
         for x in self.properties.itervalues():
             x.precompile()
+        for x in self.nested_properties.itervalues():
+            x.precompile()
         for x in self.handlers:
             x.precompile()
         for x in self.children:
@@ -671,6 +676,12 @@ class ParserRule(object):
         for name in self.properties:
             if not hasattr(widget, name):
                 widget.create_property(name)
+        for name in self.nested_properties:
+            key = name.split('.', 1)[0]
+            if not hasattr(widget, key):
+                rule = self.nested_properties[name]
+                raise ParserException(rule.ctx, rule.line,
+                    'No property {0} in {1}'.format(key, widget.__class__))
 
     def _forbid_selectors(self):
         c = self.name[0]
@@ -737,7 +748,7 @@ class Parser(object):
     CLASS_RANGE = range(ord('A'), ord('Z') + 1)
     PROP_RANGE = range(ord('A'), ord('Z') + 1) + \
                  range(ord('a'), ord('z') + 1) + \
-                 range(ord('0'), ord('9') + 1) + [ord('_')]
+                 range(ord('0'), ord('9') + 1) + [ord('_'), ord('.')]
 
     __slots__ = ('rules', 'templates', 'root', 'sourcecode',
         'directives', 'filename')
@@ -940,7 +951,10 @@ class Parser(object):
                         if name[:3] == 'on_':
                             current_object.handlers.append(rule)
                         else:
-                            current_object.properties[name] = rule
+                            if '.' in name:
+                                current_object.nested_properties[name] = rule
+                            else:
+                                current_object.properties[name] = rule
                     else:
                         current_property = name
                         current_propobject = None
@@ -968,8 +982,12 @@ class Parser(object):
                         if current_property[:3] == 'on_':
                             current_object.handlers.append(current_propobject)
                         else:
-                            current_object.properties[current_property] = \
-                                current_propobject
+                            if '.' in name:
+                                current_object.nested_properties[current_property] = \
+                                    current_propobject
+                            else:
+                                current_object.properties[current_property] = \
+                                    current_propobject
                     else:
                         current_propobject.value += '\n' + content
 
@@ -1010,7 +1028,14 @@ def create_handler(iself, element, key, value, rule, idmap):
         e_value = eval(value, idmap)
         if __debug__:
             trace('Builder: call_fn => value=%r' % (e_value, ))
-        setattr(element, key, e_value)
+        if type(key) is tuple:
+            _key, subkey = key
+            subelement = getattr(element, _key)
+            if subelement is None:
+                return
+            setattr(subelement, subkey, e_value)
+        else:
+            setattr(element, key, e_value)
 
     # bind every key.value
     if rule.watched_keys is not None:
@@ -1228,6 +1253,7 @@ class BuilderBase(object):
         assert(rule not in self.rulectx)
         self.rulectx[rule] = rctx = {
             'ids': {'root': widget},
+            'nset': [],
             'set': [], 'hdl': []}
 
         # extract the context of the rootrule (not rule!)
@@ -1311,6 +1337,8 @@ class BuilderBase(object):
         # append the properties and handlers to our final resolution task
         if rule.properties:
             rctx['set'].append((widget, rule.properties.values()))
+        if rule.nested_properties:
+            rctx['nset'].append((widget, rule.nested_properties.values()))
         if rule.handlers:
             rctx['hdl'].append((widget, rule.handlers))
 
@@ -1331,6 +1359,19 @@ class BuilderBase(object):
                             value, rule, rctx['ids'])
                 setattr(widget_set, key, value)
 
+        # now apply nested handlers
+        for widget_set, rules in reversed(rctx['nset']):
+            for rule in rules:
+                assert(isinstance(rule, ParserRuleProperty))
+                key, subkey = rule.name.split('.', 1)
+                value = rule.co_value
+                if type(value) is CodeType:
+                    value = create_handler(widget_set, widget_set, (key, subkey),
+                            value, rule, rctx['ids'])
+                element = getattr(widget_set, key)
+                if element is not None:
+                    setattr(element, subkey, value)
+
         # build handlers
         for widget_set, rules in rctx['hdl']:
             for crule in rules:

main.py

from kivy.app import App
from kivy.lang import Builder
from kivy.clock import Clock

'''
Facts:

1. can't use "self.texture_1.tex_coords", texture_1 have a bind() method, but doesn't correspond to the Property bind().
2. self.tex_coords_1 or (0, 0, 0, 0, 0, 0, 0, 0) is needed because self.tex_coords_1 is None by default
3. can't use "self.texture_1.tex_coords" because texture_1 is None at the start
'''

root = Builder.load_string(
'''
#:import Image kivy.core.image.Image
#:import time time.time
Widget:
    boottime: 0
    texture_1: Image('Sky_back_layer.png').texture
    texture_2: Image('Vegetation_(middle_layer).png').texture
    texture_3: Image('Ground_(front_layer).png').texture

    texture_1.wrap: 'repeat'
    texture_2.wrap: 'repeat'
    texture_3.wrap: 'repeat'

    texture_1.uvpos: root.boottime * 0.001, 0
    texture_2.uvpos: root.boottime * 0.01, 0
    texture_3.uvpos: root.boottime * 0.1, 0

    tex_coords_1: (getattr(self.texture_1, 'tex_coords'), root.boottime)[0]
    tex_coords_2: (getattr(self.texture_2, 'tex_coords'), root.boottime)[0]
    tex_coords_3: (getattr(self.texture_3, 'tex_coords'), root.boottime)[0]

    canvas:
        Rectangle:
            pos: self.pos
            size: self.size
            texture: self.texture_1
            tex_coords: self.tex_coords_1 or (0, 0, 0, 0, 0, 0, 0, 0)

        Rectangle:
            pos: self.pos
            size: self.size
            texture: self.texture_2
            tex_coords: self.tex_coords_2 or (0, 0, 0, 0, 0, 0, 0, 0)

        Rectangle:
            pos: self.pos
            size: self.size
            texture: self.texture_3
            tex_coords: self.tex_coords_3 or (0, 0, 0, 0, 0, 0, 0, 0)

''')


class MyApp(App):
    def build(self):
        Clock.schedule_interval(self.set_time, 0)
        return root

    def set_time(self, dt):
        self.root.boottime = Clock.get_boottime()



if __name__ == '__main__':
    MyApp().run()