added ScadInterface (SolidCode#181, SolidCode#180, SolidCode#178, SolidCode#165, #61)

Author: jeff-dh

solid/__init__.py

@@ -6,6 +6,7 @@
 from .solidpython import OpenSCADObject, IncludedOpenSCADObject
 from .objects import *
 from .patch_euclid import run_euclid_patch
+from .scad_interface import ScadInterface
 
 # Type hints
-from .objects import P2, P3, P4, Vec3 , Vec4, Vec34, P3s, P23, Points, Indexes, ScadSize, OpenSCADObjectPlus
+from .objects import P2, P3, P4, Vec3 , Vec4, Vec34, P3s, P23, Points, Indexes, ScadSize, OpenSCADObjectPlus

solid/examples/scad_interface_example.py

@@ -0,0 +1,15 @@
+from solid import *
+
+scad = ScadInterface()
+
+scad.set_global_var("$fn", 6)
+
+scad.register_customizer_var("cyl_pos", "[1, 2, 3]")
+
+cube_pos = scad.get("cyl_pos")
+
+c = translate(cube_pos) (
+        cylinder(r=scad.inline("$t * 3"), h=scad.inline("$t * 10"))
+    )
+
+scad_render_to_file(c, scad_interface=scad)

solid/scad_interface.py

@@ -0,0 +1,40 @@
+from .solidpython import OpenSCADObject
+
+class OpenSCADConstant(OpenSCADObject):
+    def __init__(self, code):
+        super().__init__("not valid openscad code !?!?!", {})
+        self.code = code
+
+    def __repr__(self):
+        return self._render()
+
+    def _render(self, render_holes=42):
+        return self.code
+
+class ScadInterface:
+    def __init__(self):
+        self.header = ''
+
+    def register_customizer_var(self, name, value, options=''):
+        self.header += f'{name} = {value}; //{options}\n'
+
+    def set_global_var(self, name, value):
+        self.header += f'{name} = {value};\n'
+
+    def get_header_str(self):
+        return self.header
+
+    def register_font(self, filename):
+        self.header += f'use <{filename}>\n'
+
+    @staticmethod
+    def get(name):
+        return ScadInterface.inline(name)
+
+    @staticmethod
+    def inline(code):
+        return scad_inline(code)
+
+def scad_inline(code):
+    return OpenSCADConstant(code)
+

solid/solidpython.py

@@ -395,7 +395,6 @@ def _get_include_path(self, include_file_path):
         # No loadable SCAD file was found in sys.path.  Raise an error
         raise ValueError(f"Unable to find included SCAD file: {include_file_path} in sys.path")
 
-
 # =========================================
 # = Rendering Python code to OpenSCAD code=
 # =========================================
@@ -412,7 +411,7 @@ def _find_include_strings(obj: Union[IncludedOpenSCADObject, OpenSCADObject]) ->
             include_strings.update(_find_include_strings(param))
     return include_strings
 
-def scad_render(scad_object: OpenSCADObject, file_header: str = '') -> str:
+def scad_render(scad_object: OpenSCADObject, file_header: str = '', scad_interface=None) -> str:
     # Make this object the root of the tree
     root = scad_object
 
@@ -424,6 +423,9 @@ def scad_render(scad_object: OpenSCADObject, file_header: str = '') -> str:
     includes = ''.join(include_strings) + "\n"
     scad_body = root._render()
 
+    if scad_interface != None:
+        file_header += scad_interface.get_header_str()
+
     if file_header and not file_header.endswith('\n'): 
         file_header += '\n'
 
@@ -507,14 +509,15 @@ def scad_render_to_file(scad_object: OpenSCADObject,
                         filepath: PathStr=None, 
                         out_dir: PathStr=None,
                         file_header: str='', 
-                        include_orig_code: bool=True) -> str:
+                        include_orig_code: bool=True,
+                        scad_interface = None) -> str:
     header = file_header
     if include_orig_code:
         version = _get_version()
         date = datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")
         header = f"// Generated by SolidPython {version} on {date}\n" + file_header
 
-    rendered_string = scad_render(scad_object, header)
+    rendered_string = scad_render(scad_object, header, scad_interface=scad_interface)
     return _write_code_to_file(rendered_string, filepath, out_dir, include_orig_code)
 
 def _write_code_to_file(rendered_string: str,