Make 'del a[b]' work for cypclass containers

Cython/Compiler/ExprNodes.py

@@ -3835,7 +3835,13 @@ class IndexNode(_IndexingBaseNode):
             error(self.pos, "Assignment to non-lvalue of type '%s'" % node.type)
         return node
 
-    def analyse_base_and_index_types(self, env, getting=False, setting=False,
+    def analyse_del_expression(self, env):
+        node = self.analyse_base_and_index_types(env, setting=True, deleting=True)
+        if node is self and not node.is_lvalue():
+            error(self.pos, "Deleting non-lvalue of type '%s'" % node.type)
+        return node
+
+    def analyse_base_and_index_types(self, env, getting=False, setting=False, deleting=False,
                                      analyse_base=True):
         # Note: This might be cleaned up by having IndexNode
         # parsed in a saner way and only construct the tuple if
@@ -3894,6 +3900,8 @@ class IndexNode(_IndexingBaseNode):
             return self.analyse_as_pyobject(env, is_slice, getting, setting)
         elif base_type.is_ptr or base_type.is_array:
             return self.analyse_as_c_array(env, is_slice)
+        elif base_type.is_cyp_class:
+            return self.analyse_as_cyp(env, setting, deleting)
         elif base_type.is_cpp_class:
             return self.analyse_as_cpp(env, setting)
         elif base_type.is_cfunction:
@@ -3975,8 +3983,6 @@ class IndexNode(_IndexingBaseNode):
 
     def analyse_as_cpp(self, env, setting):
         base_type = self.base.type
-        if base_type.is_cyp_class and setting:
-            return self.analyse_as_cyp_setitem(env)
         function = env.lookup_operator("[]", [self.base, self.index])
         if function is None:
             error(self.pos, "Indexing '%s' not supported for index type '%s'" % (base_type, self.index.type))
@@ -3999,32 +4005,55 @@ class IndexNode(_IndexingBaseNode):
             error(self.pos, "Can't set non-reference result '%s'" % self.type)
         return self
 
-    def analyse_as_cyp_setitem(self, env):
+    def analyse_as_cyp(self, env, setting, deleting):
+        if not setting:
+            return self.analyse_as_cpp(env, setting)
+        else:
+            return self.analyse_as_cyp_setitem_or_delitem(env, deleting)
+
+    def analyse_cyp_setitem_or_delitem_method(self, env, deleting):
         base_type = self.base.type
-        function = base_type.scope.lookup_here("__setitem__")
+        function_name = "__delitem__" if deleting else "__setitem__"
+        function = base_type.scope.lookup_here(function_name)
         if function is None:
-            error(self.pos, "Setting item '%s' not supported for index type '%s'" % (base_type, self.index.type))
-            self.type = PyrexTypes.error_type
-            self.result_code = "<error>"
-            return self
+            action = "Deleting" if deleting else "Setting"
+            error(self.pos, "%s item '%s' not supported for index type '%s'" % (action, base_type, self.index.type))
+            return None
         if len(function.all_alternatives()) > 1:
-            error(self.pos, "%s.__setitem__ has several alternatives" % base_type)
+            error(self.pos, "%s.%s has several alternatives" % (function_name, base_type))
+            return None
+        func_type = function.type
+        expected_nargs = 1 if deleting else 2
+        if len(func_type.args) != expected_nargs:
+            error(self.pos, "%s.%s takes wrong number of arguments" % (function_name, base_type))
+            return None
+        return func_type
+
+    def analyse_as_cyp_setitem_or_delitem(self, env, deleting):
+        base_type = self.base.type
+        func_type = self.analyse_cyp_setitem_or_delitem_method(env, deleting)
+        if func_type is None:
             self.type = PyrexTypes.error_type
             self.result_code = "<error>"
             return self
-        func_type = function.type
         self.exception_check = func_type.exception_check
         self.exception_value = func_type.exception_value
         if self.exception_check:
             if self.exception_value is None:
                 env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
-        if len(func_type.args) != 2:
-            error(self.pos, "%s.__setitem__ takes wrong number of arguments" % base_type)
+        self.index = self.index.coerce_to(func_type.args[0].type, env)
+        if not deleting:
+            self.type = func_type.args[1].type
+        else:
+            setitem_type = self.analyse_cyp_setitem_or_delitem_method(env, deleting=False)
+            if setitem_type is None:
+                # we use the setitem method to determine the contained type
+                # so we require it be defined, as we need it to add elements anyway
+                error(self.pos, "Deleting element from collection without a __setitem__ method")
                 self.type = PyrexTypes.error_type
                 self.result_code = "<error>"
                 return self
-        self.index = self.index.coerce_to(func_type.args[0].type, env)
-        self.type = func_type.args[1].type
+            self.type = setitem_type.args[1].type
         return self
 
     def analyse_as_c_function(self, env):
@@ -4488,8 +4517,26 @@ class IndexNode(_IndexingBaseNode):
             value_code = '((unsigned char)%s)' % value_code
         return value_code
 
+    def generate_cyp_delitem_code(self, code):
+        function = self.base.type.scope.lookup_here("__delitem__")
+        function_code = function.cname
+        setitem_code = "%s->%s(%s);" % (
+                        self.base.result(),
+                        function_code,
+                        self.index.result())
+        if self.exception_check and self.exception_check == "+":
+            translate_cpp_exception(code, self.pos,
+                    setitem_code,
+                    None,
+                    self.exception_value, self.in_nogil_context)
+        else:
+            code.putln(setitem_code)
+
     def generate_deletion_code(self, code, ignore_nonexisting=False):
         self.generate_subexpr_evaluation_code(code)
+        if self.base.type.is_cyp_class:
+            self.generate_cyp_delitem_code(code)
+        else:
             #if self.type.is_pyobject:
             if self.index.type.is_int:
                 function = "__Pyx_DelItemInt"

Cython/Compiler/Nodes.py

@@ -6505,6 +6505,9 @@ class DelStatNode(StatNode):
 
     def analyse_expressions(self, env):
         for i, arg in enumerate(self.args):
+            if arg.is_subscript:
+                arg = self.args[i] = arg.analyse_del_expression(env)
+            else:
                 arg = self.args[i] = arg.analyse_target_expression(env, None)
             arg.ensure_lhs_locked(env)
             if arg.type.is_pyobject or (arg.is_name and arg.type.is_memoryviewslice):
@@ -6535,7 +6538,8 @@ class DelStatNode(StatNode):
         for arg in self.args:
             if (arg.type.is_pyobject or
                     arg.type.is_memoryviewslice or
-                    arg.is_subscript and arg.base.type is Builtin.bytearray_type):
+                    arg.is_subscript and arg.base.type is Builtin.bytearray_type or
+                    arg.is_subscript and arg.base.type.is_cyp_class):
                 arg.generate_deletion_code(
                     code, ignore_nonexisting=self.ignore_nonexisting)
             elif arg.type.is_ptr and arg.type.base_type.is_cpp_class:
@@ -6547,6 +6551,7 @@ class DelStatNode(StatNode):
                 arg.generate_evaluation_code(code)
                 if arg.type.lock_mode == "autolock" and self.was_locked:
                     code.putln("Cy_UNLOCK(%s);" % arg.result())
+                else:
                     code.putln("Cy_DECREF(%s);" % arg.result())
                     code.putln("%s = NULL;" % arg.result())
                 arg.generate_disposal_code(code)