Primitives for all constant blocks (add screen dimensions, update colors)

  - Use the get() method of the CONSTANTS dict to retrieve the values of
    constants, but export it as CONSTANTS['key'].
  - Introduce the new class TypedSubscript for Subscript ASTs with a type.

6 files changed, 74 insertions, 32 deletions

diff --git a/TurtleArt/tabasics.py b/TurtleArt/tabasics.py
index fc769b0..d84b169 100644
--- a/TurtleArt/tabasics.py
+++ b/TurtleArt/tabasics.py
@@ -1422,5 +1422,5 @@ variable'))
                           prim_name=block_name,
                           logo_command=value)
         self.tw.lc.def_prim(block_name, 0,
-            Primitive(Primitive.identity, return_type=TYPE_COLOR,
-                      arg_descs=[ConstantArg(constant)]))
+            Primitive(CONSTANTS.get, return_type=TYPE_COLOR,
+                      arg_descs=[ConstantArg(str(constant))]))
diff --git a/TurtleArt/taexportpython.py b/TurtleArt/taexportpython.py
index db00add..d41ec98 100644
--- a/TurtleArt/taexportpython.py
+++ b/TurtleArt/taexportpython.py
@@ -136,6 +136,7 @@ def _walk_action_stack(top_block, lc, convert_me=True):
     block = top_block
 
     # value blocks don't have a primitive
+    # (but constant blocks (colors, screen dimensions, etc.) do)
     if block.is_value_block():
         raw_value = block.get_value(add_type_prefix=False)
         if convert_me:
diff --git a/TurtleArt/taprimitive.py b/TurtleArt/taprimitive.py
index 956f50d..f969e96 100644
--- a/TurtleArt/taprimitive.py
+++ b/TurtleArt/taprimitive.py
@@ -452,6 +452,12 @@ class Primitive(object):
                 raise ValueError("Primitive.identity got unexpected number "
                                  "of arguments (%d)" % (len(new_arg_asts)))
 
+        # constant
+        elif self == CONSTANTS.get:
+            return TypedSubscript(value=ast.Name(id='CONSTANTS', ctx=ast.Load),
+                                  slice_=ast.Index(value=new_arg_asts[0]),
+                                  return_type=self.return_type)
+
         # group of Primitives or sandwich-clamp block
         elif self in (Primitive.group, LogoCode.prim_clamp):
             ast_list = []
@@ -1052,17 +1058,11 @@ def value_to_ast(value, *args_for_prim, **kwargs_for_prim):
                 ast_list.append(item_ast)
         return ast.List(elts=ast_list, ctx=ast.Load)
     elif isinstance(value, Color):
-        if str(value) in CONSTANTS:
-            # repr(str(value)) is necessary; it first converts the Color to a
-            # string and then adds appropriate quotes around that string
-            return ast.Name(id='CONSTANTS[%s]' % repr(str(value)),
-                            ctx=ast.Load)
-        else:
-            # call to the Color constructor with this object's values,
-            # e.g., Color('red', 0, 50, 100)
-            return get_call_ast('Color', [value.name, value.color,
-                                          value.shade, value.gray],
-                                return_type=TYPE_COLOR)
+        # call to the Color constructor with this object's values,
+        # e.g., Color('red', 0, 50, 100)
+        return get_call_ast('Color', [value.name, value.color,
+                                      value.shade, value.gray],
+                            return_type=TYPE_COLOR)
     else:
         raise ValueError("unknown type of raw value: " + repr(type(value)))
 
diff --git a/TurtleArt/tatype.py b/TurtleArt/tatype.py
index 752f71b..9a8c17d 100644
--- a/TurtleArt/tatype.py
+++ b/TurtleArt/tatype.py
@@ -350,7 +350,17 @@ def convert(x, new_type, old_type=None, converter=None):
         return _apply_converter(converter, x)
 
 
-class TypedCall(ast.Call):
+class TypedAST(ast.AST):
+
+    @property
+    def return_type(self):
+        if self._return_type is None:
+            return get_type(self.func)[0]
+        else:
+            return self._return_type
+
+
+class TypedCall(ast.Call,TypedAST):
     """ Like a Call AST, but with a return type """
 
     def __init__(self, func, args=None, keywords=None, starargs=None,
@@ -366,12 +376,15 @@ class TypedCall(ast.Call):
 
         self._return_type = return_type
 
-    @property
-    def return_type(self):
-        if self._return_type is None:
-            return get_type(self.func)[0]
-        else:
-            return self._return_type
+
+class TypedSubscript(ast.Subscript,TypedAST):
+    """ Like a Subscript AST, but with a return type """
+
+    def __init__(self, value, slice_, ctx=ast.Load, return_type=None):
+
+        ast.Subscript.__init__(self, value=value, slice=slice_, ctx=ctx)
+
+        self._return_type = return_type
 
 
 def get_call_ast(func_name, args=None, kwargs=None, return_type=None):
diff --git a/plugins/turtle_blocks_extras/turtle_blocks_extras.py b/plugins/turtle_blocks_extras/turtle_blocks_extras.py
index 041dc24..8538d89 100644
--- a/plugins/turtle_blocks_extras/turtle_blocks_extras.py
+++ b/plugins/turtle_blocks_extras/turtle_blocks_extras.py
@@ -880,7 +880,9 @@ Journal objects'))
                           prim_name='lpos',
                           logo_command='lpos',
                           help_string=_('xcor of left of screen'))
-        self.tw.lc.def_prim('lpos', 0, lambda self: CONSTANTS['leftpos'])
+        self.tw.lc.def_prim('lpos', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('leftpos')]))
 
         palette.add_block('bottompos',
                           style='box-style',
@@ -888,7 +890,9 @@ Journal objects'))
                           prim_name='bpos',
                           logo_command='bpos',
                           help_string=_('ycor of bottom of screen'))
-        self.tw.lc.def_prim('bpos', 0, lambda self: CONSTANTS['bottompos'])
+        self.tw.lc.def_prim('bpos', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('bottompos')]))
 
         palette.add_block('width',
                           style='box-style',
@@ -896,7 +900,9 @@ Journal objects'))
                           prim_name='hres',
                           logo_command='width',
                           help_string=_('the canvas width'))
-        self.tw.lc.def_prim('hres', 0, lambda self: CONSTANTS['width'])
+        self.tw.lc.def_prim('hres', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('width')]))
 
         palette.add_block('rightpos',
                           style='box-style',
@@ -904,7 +910,9 @@ Journal objects'))
                           prim_name='rpos',
                           logo_command='rpos',
                           help_string=_('xcor of right of screen'))
-        self.tw.lc.def_prim('rpos', 0, lambda self: CONSTANTS['rightpos'])
+        self.tw.lc.def_prim('rpos', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('rightpos')]))
 
         palette.add_block('toppos',
                           style='box-style',
@@ -912,7 +920,9 @@ Journal objects'))
                           prim_name='tpos',
                           logo_command='tpos',
                           help_string=_('ycor of top of screen'))
-        self.tw.lc.def_prim('tpos', 0, lambda self: CONSTANTS['toppos'])
+        self.tw.lc.def_prim('tpos', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('toppos')]))
 
         palette.add_block('height',
                           style='box-style',
@@ -920,7 +930,9 @@ Journal objects'))
                           prim_name='vres',
                           logo_command='height',
                           help_string=_('the canvas height'))
-        self.tw.lc.def_prim('vres', 0, lambda self: CONSTANTS['height'])
+        self.tw.lc.def_prim('vres', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('height')]))
 
         palette.add_block('titlex',
                           hidden=True,
@@ -929,7 +941,9 @@ Journal objects'))
                           label=_('title x'),
                           logo_command='titlex',
                           prim_name='titlex')
-        self.tw.lc.def_prim('titlex', 0, lambda self: CONSTANTS['titlex'])
+        self.tw.lc.def_prim('titlex', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('titlex')]))
 
         palette.add_block('titley',
                           hidden=True,
@@ -938,7 +952,9 @@ Journal objects'))
                           label=_('title y'),
                           logo_command='titley',
                           prim_name='titley')
-        self.tw.lc.def_prim('titley', 0, lambda self: CONSTANTS['titley'])
+        self.tw.lc.def_prim('titley', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('titley')]))
 
         palette.add_block('leftx',
                           hidden=True,
@@ -947,7 +963,9 @@ Journal objects'))
                           label=_('left x'),
                           prim_name='leftx',
                           logo_command='leftx')
-        self.tw.lc.def_prim('leftx', 0, lambda self: CONSTANTS['leftx'])
+        self.tw.lc.def_prim('leftx', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('leftx')]))
 
         palette.add_block('topy',
                           hidden=True,
@@ -956,7 +974,9 @@ Journal objects'))
                           label=_('top y'),
                           prim_name='topy',
                           logo_command='topy')
-        self.tw.lc.def_prim('topy', 0, lambda self: CONSTANTS['topy'])
+        self.tw.lc.def_prim('topy', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('topy')]))
 
         palette.add_block('rightx',
                           hidden=True,
@@ -965,7 +985,9 @@ Journal objects'))
                           label=_('right x'),
                           prim_name='rightx',
                           logo_command='rightx')
-        self.tw.lc.def_prim('rightx', 0, lambda self: CONSTANTS['rightx'])
+        self.tw.lc.def_prim('rightx', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('rightx')]))
 
         palette.add_block('bottomy',
                           hidden=True,
@@ -974,7 +996,9 @@ Journal objects'))
                           label=_('bottom y'),
                           prim_name='bottomy',
                           logo_command='bottomy')
-        self.tw.lc.def_prim('bottomy', 0, lambda self: CONSTANTS['bottomy'])
+        self.tw.lc.def_prim('bottomy', 0,
+            Primitive(CONSTANTS.get, return_type=TYPE_INT,
+                arg_descs=[ConstantArg('bottomy')]))
 
     def _myblocks_palette(self):
         ''' User-defined macros are saved as a json-encoded file;
diff --git a/util/codegen.py b/util/codegen.py
index 5f768f8..6e4d383 100644
--- a/util/codegen.py
+++ b/util/codegen.py
@@ -477,6 +477,10 @@ class SourceGenerator(NodeVisitor):
         self.write('[')
         self.visit(node.slice)
         self.write(']')
+    visit_TypedSubscript = visit_Subscript
+
+    def visit_Index(self, node):
+        self.visit(node.value)
 
     def visit_Slice(self, node):
         if node.lower is not None: