move cython shadow module to fontTools.misc

Lib/fontTools/cu2qu.py

@@ -19,19 +19,7 @@ try:
     import cython
 except ImportError:
     # if cython not installed, use mock module with no-op decorators and types
-    from types import SimpleNamespace
-
-    def _empty_decorator(x):
-        return x
-
-    cython = SimpleNamespace()
-    cython.compiled = False
-    for name in ("double", "complex", "int"):
-        setattr(cython, name, None)
-    for name in ("cfunc", "inline"):
-        setattr(cython, name, _empty_decorator)
-    cython.locals = lambda **_: _empty_decorator
-    cython.returns = lambda _: _empty_decorator
+    from fontTools.misc import cython
 
 import math
 

Lib/fontTools/misc/cython.py

@@ -0,0 +1,25 @@
+""" Exports a no-op 'cython' namespace similar to
+https://github.com/cython/cython/blob/master/Cython/Shadow.py
+
+This allows to optionally compile @cython decorated functions
+(when cython is available at built time), or run the same code
+as pure-python, without runtime dependency on cython module.
+
+We only define the symbols that we use. E.g. see fontTools.cu2qu
+"""
+
+from types import SimpleNamespace
+
+def _empty_decorator(x):
+    return x
+
+compiled = False
+
+for name in ("double", "complex", "int"):
+    globals()[name] = None
+
+for name in ("cfunc", "inline"):
+    globals()[name] = _empty_decorator
+
+locals = lambda **_: _empty_decorator
+returns = lambda _: _empty_decorator