Merge pull request #539 from krekoten/method_arity

Method arity almost completed

spec/tags/core/method/arity_tags.txt

@@ -1,6 +1 @@
-fails:Method#arity returns n, where n is the number of required arguments, when there are zero or more required arguments only
-fails:Method#arity returns n, where n is the number of required arguments and method created via defined_method
-fails:Method#arity returns -(n+1), where n is the number of required arguments, when there is at least one optional argument
-fails:Method#arity returns -(n+1), where n is the number of required arguments, when there is a splat argument, regardless of optional arguments
-fails:Method#arity returns the same value regardless of the presence of a block
 fails:Method#arity for a Method generated by respond_to_missing? returns -1

topaz/objects/functionobject.py

@@ -17,6 +17,9 @@ def __deepcopy__(self, memo):
         obj.w_class = copy.deepcopy(self.w_class, memo)
         return obj
 
+    def arity(self, space):
+        return space.newint(0)
+
 
 class W_UserFunction(W_FunctionObject):
     _immutable_fields_ = ["bytecode", "lexical_scope"]
@@ -43,6 +46,13 @@ def call(self, space, w_receiver, args_w, block):
             frame.handle_args(space, self.bytecode, args_w, block)
             return space.execute_frame(frame, self.bytecode)
 
+    def arity(self, space):
+        args_count = len(self.bytecode.arg_pos) - len(self.bytecode.defaults)
+        if len(self.bytecode.defaults) > 0 or self.bytecode.splat_arg_pos != -1:
+            args_count = -(args_count + 1)
+
+        return space.newint(args_count)
+
 
 class W_BuiltinFunction(W_FunctionObject):
     _immutable_fields_ = ["func"]

topaz/objects/methodobject.py

@@ -1,4 +1,7 @@
 from topaz.module import ClassDef
+from topaz.objects.blockobject import W_BlockObject
+from topaz.objects.functionobject import W_UserFunction
+from topaz.objects.moduleobject import AttributeWriter, DefineMethodBlock
 from topaz.objects.objectobject import W_Object
 
 
@@ -58,6 +61,10 @@ def method_eql(self, space, w_other):
         else:
             return space.w_false
 
+    @classdef.method("arity")
+    def method_arity(self, space):
+        return self.w_function.arity(space)
+
 
 class W_UnboundMethodObject(W_Object):
     classdef = ClassDef("UnboundMethod", W_Object.classdef, filepath=__file__)

topaz/objects/moduleobject.py

@@ -30,6 +30,9 @@ def call(self, space, w_obj, args_w, block):
         space.set_instance_var(w_obj, self.varname, w_value)
         return w_value
 
+    def arity(self, space):
+        return space.newint(1)
+
 
 class UndefMethod(W_FunctionObject):
     _immutable_fields_ = ["name"]
@@ -53,6 +56,13 @@ def call(self, space, w_obj, args_w, block):
         method_block = self.block.copy(w_self=w_obj)
         return space.invoke_block(method_block, args_w, block)
 
+    def arity(self, space):
+        args_count = len(self.block.bytecode.arg_pos) - len(self.block.bytecode.defaults)
+        if len(self.block.bytecode.defaults) > 0 or self.block.bytecode.splat_arg_pos != -1:
+            args_count = -(args_count + 1)
+
+        return space.newint(args_count)
+
 
 class DefineMethodMethod(W_FunctionObject):
     _immutable_fields_ = ["name", "w_unbound_method"]