Merge pull request #698 from kostya/subscript

fix #661 simplify array subscript access nil check

spec/tags/core/array/element_reference_tags.txt

@@ -1,9 +1,3 @@
 fails:Array#[] raises a RangeError when the start index is out of range of Fixnum
 fails:Array#[] raises a RangeError when the length is out of range of Fixnum
-fails:Array#[] with a subclass of Array returns a subclass instance with [n, m]
-fails:Array#[] with a subclass of Array returns a subclass instance with [-n, m]
-fails:Array#[] with a subclass of Array returns a subclass instance with [n..m]
-fails:Array#[] with a subclass of Array returns a subclass instance with [n...m]
-fails:Array#[] with a subclass of Array returns a subclass instance with [-n..-m]
-fails:Array#[] with a subclass of Array returns a subclass instance with [-n...-m]
 fails:Array.[] can unpack 2 or more nested referenced array

spec/tags/core/array/slice_tags.txt

@@ -1,8 +1,2 @@
 fails:Array#slice raises a RangeError when the start index is out of range of Fixnum
 fails:Array#slice raises a RangeError when the length is out of range of Fixnum
-fails:Array#slice with a subclass of Array returns a subclass instance with [n, m]
-fails:Array#slice with a subclass of Array returns a subclass instance with [-n, m]
-fails:Array#slice with a subclass of Array returns a subclass instance with [n..m]
-fails:Array#slice with a subclass of Array returns a subclass instance with [n...m]
-fails:Array#slice with a subclass of Array returns a subclass instance with [-n..-m]
-fails:Array#slice with a subclass of Array returns a subclass instance with [-n...-m]

topaz/objects/arrayobject.py

@@ -75,7 +75,7 @@ def method_subscript(self, space, w_idx, w_count=None):
         elif as_range:
             assert start >= 0
             assert end >= 0
-            return space.newarray(self.items_w[start:end])
+            return W_ArrayObject(space, self.items_w[start:end], space.getnonsingletonclass(self))
         else:
             return self.items_w[start]
 
@@ -87,7 +87,7 @@ def method_subscript_assign(self, space, w_idx, w_count_or_obj, w_obj=None):
             w_count = w_count_or_obj
         else:
             w_obj = w_count_or_obj
-        start, end, as_range, nil = space.subscript_access(len(self.items_w), w_idx, w_count=w_count)
+        start, end, as_range, _ = space.subscript_access(len(self.items_w), w_idx, w_count=w_count)
 
         if w_count and end < start:
             raise space.error(space.w_IndexError,

topaz/objspace.py

@@ -653,6 +653,7 @@ def subscript_access(self, length, w_idx, w_count):
         inclusive = False
         as_range = False
         end = 0
+        nil = False
 
         if isinstance(w_idx, W_RangeObject) and not w_count:
             start = self.int_w(self.convert_type(w_idx.w_start, self.w_fixnum, "to_int"))
@@ -665,9 +666,14 @@ def subscript_access(self, length, w_idx, w_count):
                 end = self.int_w(self.convert_type(w_count, self.w_fixnum, "to_int"))
                 if end >= 0:
                     as_range = True
+                else:
+                    if start < 0:
+                        start += length
+                    return (start, end, False, True)
 
         if start < 0:
             start += length
+
         if as_range:
             if w_count:
                 end += start
@@ -679,9 +685,10 @@ def subscript_access(self, length, w_idx, w_count):
                 end = start
             elif end > length:
                 end = length
+            nil = start < 0 or end < 0 or start > length
+        else:
+            nil = start < 0 or start >= length
 
-        nil = ((not as_range and start >= length) or
-            start < 0 or end < 0 or (start > 0 and start > length))
         return (start, end, as_range, nil)
 
     def convert_type(self, w_obj, w_cls, method, raise_error=True):