convert to new primitive type

1 files changed, 16 insertions, 7 deletions

diff --git a/pysamples/uturn.py b/pysamples/uturn.py
index cdeb96d..60683a0 100644
--- a/pysamples/uturn.py
+++ b/pysamples/uturn.py
@@ -1,4 +1,4 @@
-#Copyright (c) 2011, Walter Bender
+ #Copyright (c) 2011-2013, Walter Bender
 
 # This procedure is invoked when the user-definable block on the
 # "extras" palette is selected.
@@ -8,11 +8,22 @@
 # can use the u-turn block as you would any other block.
 
 
-def myblock(tw, arg):
+def myblock(tw, args):
     ''' Add a uturn block to the 'turtle' palette '''
 
+    # def_prim takes 3 arguments: the primitive name, the number of
+    # arguments -- 0 in this case -- and the function to call -- in this
+    # case, we define the _prim_uturn function to set heading += 180.
+    def _prim_uturn(tw):
+        value = tw.turtles.get_active_turtle().get_heading() + 180
+        tw.turtles.get_active_turtle().set_heading(value)
+        # We also update the label on the heading block to indicate
+        # the current heading value
+        if tw.lc.update_values:
+            tw.lc.update_label_value('heading', value)
+
     from TurtleArt.tapalette import make_palette, palette_name_to_index
-    from TurtleArt.talogo import primitive_dictionary
+    from TurtleArt.taprimitive import Primitive, ConstantArg
     from gettext import gettext as _
 
     # Choose a palette for the new block.
@@ -23,12 +34,10 @@ def myblock(tw, arg):
                       style='basic-style-extended-vertical',
                       label=_('uturn'),
                       prim_name='uturn',
-                      help_string=_('make a uturn'))
+                      help_string=_('turns the turtle 180 degrees'))
 
     # Add its primitive to the LogoCode dictionary.
-    tw.lc.def_prim('uturn', 0,
-                   lambda self: primitive_dictionary['set']
-                   ('heading', tw.canvas.seth, tw.canvas.heading + 180))
+    tw.lc.def_prim('uturn', 0, Primitive(_prim_uturn, arg_descs=[ConstantArg(tw)]))
 
     # Regenerate the palette, which will now include the new block.
     tw.show_toolbar_palette(palette_name_to_index('turtle'),