PythonFunctionGenerator: add decorator support

Author: matthiasdiener

pytools/py_codegen.py

@@ -52,10 +52,14 @@ def get_picklable_module(self, name=None):
 
 
 class PythonFunctionGenerator(PythonCodeGenerator):
-    def __init__(self, name, args):
+    def __init__(self, name, args, decorators=None):
         PythonCodeGenerator.__init__(self)
         self.name = name
 
+        if decorators:
+            for decorator in decorators:
+                self(decorator)
+
         self("def {}({}):".format(name, ", ".join(args)))
         self.indent()
 

pytools/test/test_py_codegen.py

@@ -2,6 +2,8 @@
 
 import sys
 
+import pytest
+
 import pytools
 import pytools.py_codegen as codegen
 
@@ -30,6 +32,41 @@ def test_picklable_function():
     assert f() == 1
 
 
+def test_function_decorators(capfd):
+    cg = codegen.PythonFunctionGenerator("f", args=(), decorators=["@staticmethod"])
+    cg("return 42")
+
+    assert cg.get_function()() == 42
+
+    cg = codegen.PythonFunctionGenerator("f", args=(), decorators=["@classmethod"])
+    cg("return 42")
+
+    with pytest.raises(TypeError):
+        cg.get_function()()
+
+    cg = codegen.PythonFunctionGenerator("f", args=(),
+                                         decorators=["@staticmethod", "@classmethod"])
+    cg("return 42")
+
+    with pytest.raises(TypeError):
+        cg.get_function()()
+
+    cg = codegen.PythonFunctionGenerator("f", args=("x"),
+                decorators=["from functools import lru_cache", "@lru_cache"])
+    cg("print('Hello World!')")
+    cg("return 42")
+
+    f = cg.get_function()
+
+    assert f(0) == 42
+    out, _err = capfd.readouterr()
+    assert out == "Hello World!\n"
+
+    assert f(0) == 42
+    out, _err = capfd.readouterr()
+    assert out == ""  # second print is not executed due to lru_cache
+
+
 if __name__ == "__main__":
     if len(sys.argv) > 1:
         exec(sys.argv[1])