Basic support for some elements of ImplicitCAD, as suggested in #134

Author: etjones-erisyon

solid/implicit.py

@@ -0,0 +1,58 @@
+#! /usr/bin/env python
+import solid.objects
+from solid.solidpython import calling_module, OpenSCADObject
+
+from textwrap import dedent
+from typing import  Dict, Callable
+
+def implicitCAD_patch_objects():
+    """
+    Usage: 
+    `from solid.implicit import *`, (rather than `from solid import *`)
+    All other usage should be like normal SolidPython.
+
+    Monkey-patching for basic compatibility with Christopher Olah's ImplicitCAD
+    (https://github.com/colah/ImplicitCAD)
+    NOTE that this *only* enables `r` arguments to a number of geometry classes.
+    ImplicitCAD has a number of other syntax features that are still unsupported,
+    notably functions as arguments to some functions. PRs for that are welcome!
+    -ETJ 22 January 2020
+
+    """
+    to_add_rad = [ 
+        'square', 'polygon', 
+        'cube', 'cylinder', 'polyhedron', 
+        'union', 'intersection', 'difference'
+    ]
+        
+    cur_mod = calling_module(stack_depth=1)
+
+    for cls_name, cls in solid.objects.__dict__.items():
+        if cls_name in to_add_rad:
+            args_dict_orig = method_args_dict(cls.__init__)
+            args_str_orig = ', '.join(['self'] + [f'{k} = {v}' for k, v in args_dict_orig.items()])
+            args_str = ', '.join([args_str_orig, 'r = 0'])
+            super_args_str = ', '.join([f'{k} = {k}' for k in args_dict_orig.keys()])
+
+            cls_str = dedent(f'''
+            class {cls_name}(solid.objects.{cls_name}):
+                def __init__({args_str}):
+                    super().__init__({super_args_str})
+                    self.params['r'] = r
+
+            ''')
+            exec(cls_str)
+
+            cls = locals()[cls_name]
+
+        # Add the class (original or new subclass) to this module's top level namespace
+        setattr(cur_mod, cls_name, cls)
+
+def method_args_dict(method:Callable) -> Dict:
+    var_names = method.__code__.co_varnames
+    var_names = tuple((v for v in var_names if v is not 'self'))
+    default_vals = method.__defaults__ or [None] # type:ignore
+
+    return dict(zip(var_names, default_vals))
+
+implicitCAD_patch_objects()