Add PyCall.setattr and PyCall.delattr

Author: mrkn

ext/pycall/libpython.c

@@ -110,6 +110,7 @@ pycall_init_libpython_api_table(VALUE libpython_handle)
   INIT_API_TABLE_ENTRY(PyObject_GetAttrString, required);
   INIT_API_TABLE_ENTRY(PyObject_SetAttrString, required);
   INIT_API_TABLE_ENTRY(PyObject_HasAttrString, required);
+  INIT_API_TABLE_ENTRY(PyObject_DelAttrString, optional);
   INIT_API_TABLE_ENTRY(PyObject_GetItem, required);
   INIT_API_TABLE_ENTRY(PyObject_SetItem, required);
   INIT_API_TABLE_ENTRY(PyObject_DelItem, required);

ext/pycall/pycall.c

@@ -861,6 +861,51 @@ pycall_libpython_helpers_m_hasattr_p(VALUE mod, VALUE pyptr, VALUE name)
   return res ? Qtrue : Qfalse;
 }
 
+static VALUE
+pycall_libpython_helpers_m_setattr(VALUE mod, VALUE pyptr, VALUE name, VALUE val)
+{
+  PyObject *pyobj, *pyval;
+
+  if (!is_pycall_pyptr(pyptr)) {
+    rb_raise(rb_eTypeError, "PyCall::PyPtr is required");
+  }
+
+  pyobj = get_pyobj_ptr(pyptr);
+
+  if (RB_TYPE_P(name, T_SYMBOL)) {
+    name = rb_sym_to_s(name);
+  }
+
+  pyval = pycall_pyobject_from_ruby(val);
+  if (Py_API(PyObject_SetAttrString)(pyobj, StringValueCStr(name), pyval) == -1) {
+    pycall_pyerror_fetch_and_raise("PyObject_SetAttrString");
+  }
+
+  return Qnil;
+}
+
+static VALUE
+pycall_libpython_helpers_m_delattr(VALUE mod, VALUE pyptr, VALUE name)
+{
+  PyObject *pyobj;
+
+  if (!is_pycall_pyptr(pyptr)) {
+    rb_raise(rb_eTypeError, "PyCall::PyPtr is required");
+  }
+
+  pyobj = get_pyobj_ptr(pyptr);
+
+  if (RB_TYPE_P(name, T_SYMBOL)) {
+    name = rb_sym_to_s(name);
+  }
+
+  if (Py_API(PyObject_DelAttrString)(pyobj, StringValueCStr(name)) == -1) {
+    pycall_pyerror_fetch_and_raise("PyObject_DelAttrString");
+  }
+
+  return Qnil;
+}
+
 static VALUE
 pycall_libpython_helpers_m_callable_p(VALUE mod, VALUE pyptr)
 {
@@ -2074,11 +2119,24 @@ pycall_pystring_from_formatv(char const *format, va_list vargs)
 
 /* ==== Python ==== */
 
+int
+pycall_PyObject_DelAttrString(PyObject *pyobj, const char *attr_name)
+{
+  /* PyObject_DelAttrString is defined by using PyObject_SetAttrString in CPython's abstract.h */
+  return Py_API(PyObject_SetAttrString)(pyobj, attr_name, NULL);
+}
+
 static void
 init_python(void)
 {
   static char const *argv[1] = { "" };
 
+  /* optional functions */
+  if (! Py_API(PyObject_DelAttrString)) {
+    /* The case of PyObject_DelAttrString as a macro */
+    Py_API(PyObject_DelAttrString) = pycall_PyObject_DelAttrString;
+  }
+
   Py_API(Py_InitializeEx)(0);
   Py_API(PySys_SetArgvEx)(0, (char **)argv, 0);
 
@@ -2301,6 +2359,8 @@ Init_pycall(void)
   rb_define_module_function(mHelpers, "compare", pycall_libpython_helpers_m_compare, 3);
   rb_define_module_function(mHelpers, "getattr", pycall_libpython_helpers_m_getattr, -1);
   rb_define_module_function(mHelpers, "hasattr?", pycall_libpython_helpers_m_hasattr_p, 2);
+  rb_define_module_function(mHelpers, "setattr", pycall_libpython_helpers_m_setattr, 3);
+  rb_define_module_function(mHelpers, "delattr", pycall_libpython_helpers_m_delattr, 2);
   rb_define_module_function(mHelpers, "callable?", pycall_libpython_helpers_m_callable_p, 1);
   rb_define_module_function(mHelpers, "call_object", pycall_libpython_helpers_m_call_object, -1);
   rb_define_module_function(mHelpers, "getitem", pycall_libpython_helpers_m_getitem, 2);

ext/pycall/pycall_internal.h

@@ -568,6 +568,7 @@ typedef struct {
   PyObject * (* PyObject_GetAttrString)(PyObject *, char const *);
   int (* PyObject_SetAttrString)(PyObject *, char const *, PyObject *);
   int (* PyObject_HasAttrString)(PyObject *, char const *);
+  int (* PyObject_DelAttrString)(PyObject *, char const *);
   PyObject * (* PyObject_GetItem)(PyObject *, PyObject *);
   int (* PyObject_SetItem)(PyObject *obj, PyObject *key, PyObject *value);
   int (* PyObject_DelItem)(PyObject *, PyObject *);

lib/pycall.rb

@@ -59,6 +59,14 @@ def hasattr?(obj, name)
     LibPython::Helpers.hasattr?(obj.__pyptr__, name)
   end
 
+  def setattr(obj, name, val)
+    LibPython::Helpers.setattr(obj.__pyptr__, name, val)
+  end
+
+  def delattr(obj, name)
+    LibPython::Helpers.delattr(obj.__pyptr__, name)
+  end
+
   def same?(left, right)
     case left
     when PyObjectWrapper

test/python/pycall/simple_class.py

@@ -0,0 +1,13 @@
+class SimpleClass(object):
+    class NestedClass:
+        pass
+
+    def __init__(self, x=0):
+        self.x = x
+
+    def initialize(self, x):
+        self.x = x
+        return 'initialized'
+
+class SimpleSubClass(SimpleClass):
+    pass

test/test-pycall.rb

@@ -3,6 +3,24 @@ def test_VERSION
     assert_not_nil(PyCall::VERSION)
   end
 
+  def test_setattr
+    simple_class = PyCall.import_module("pycall.simple_class").SimpleClass
+    pyobj = simple_class.new(42)
+    before = pyobj.x
+    PyCall.setattr(pyobj, :x, 1)
+    assert_equal([42, 1],
+                 [before, pyobj.x])
+  end
+
+  def test_delattr
+    simple_class = PyCall.import_module("pycall.simple_class").SimpleClass
+    pyobj = simple_class.new(42)
+    PyCall.delattr(pyobj, :x)
+    assert do
+      not PyCall.hasattr?(pyobj, :x)
+    end
+  end
+
   def test_iterable
     simple_iterable = PyCall.import_module("pycall.simple_iterable")
     int_gen = simple_iterable.IntGenerator.new(10, 25)