allow list literals with a constant multiplier to be assigned to C arrays,...

allow list literals with a constant multiplier to be assigned to C arrays, extend array assignment tests

Cython/Compiler/ExprNodes.py

@@ -3947,6 +3947,11 @@ class SliceIndexNode(ExprNode):
                     "default encoding required for conversion from '%s' to '%s'" %
                     (self.base.type, dst_type))
             self.type = dst_type
+        if dst_type.is_array and self.base.type.is_array:
+            if not self.start and not self.stop:
+                # redundant slice building, copy C arrays directly
+                return self.base.coerce_to(dst_type, env)
+            # else: check array size if possible
         return super(SliceIndexNode, self).coerce_to(dst_type, env)
 
     def generate_result_code(self, code):
@@ -6553,16 +6558,25 @@ class ListNode(SequenceNode):
             self.obj_conversion_errors = []
             if not self.type.subtype_of(dst_type):
                 error(self.pos, "Cannot coerce list to type '%s'" % dst_type)
-        elif self.mult_factor:
-            error(self.pos, "Cannot coerce multiplied list to '%s'" % dst_type)
         elif (dst_type.is_array or dst_type.is_ptr) and dst_type.base_type is not PyrexTypes.c_void_type:
+            array_length = len(self.args)
+            if self.mult_factor:
+                if isinstance(self.mult_factor.constant_result, (int, long)):
+                    if self.mult_factor.constant_result <= 0:
+                        error(self.pos, "Cannot coerce non-positively multiplied list to '%s'" % dst_type)
+                    else:
+                        array_length *= self.mult_factor.constant_result
+                else:
+                    error(self.pos, "Cannot coerce dynamically multiplied list to '%s'" % dst_type)
             base_type = dst_type.base_type
-            self.type = PyrexTypes.CArrayType(base_type, len(self.args))
+            self.type = PyrexTypes.CArrayType(base_type, array_length)
             for i in range(len(self.original_args)):
                 arg = self.args[i]
                 if isinstance(arg, CoerceToPyTypeNode):
                     arg = arg.arg
                 self.args[i] = arg.coerce_to(base_type, env)
+        elif self.mult_factor:
+            error(self.pos, "Cannot coerce multiplied list to '%s'" % dst_type)
         elif dst_type.is_struct:
             if len(self.args) > len(dst_type.scope.var_entries):
                 error(self.pos, "Too may members for '%s'" % dst_type)
@@ -6619,11 +6633,23 @@ class ListNode(SequenceNode):
                 report_error(err)
             self.generate_sequence_packing_code(code)
         elif self.type.is_array:
+            if self.mult_factor:
+                code.putln("{")
+                code.putln("Py_ssize_t %s;" % Naming.quick_temp_cname)
+                code.putln("for ({i} = 0; {i} < {count}; {i}++) {{".format(
+                    i=Naming.quick_temp_cname, count=self.mult_factor.result()))
+                offset = '+ (%d * %s)' % (len(self.args), Naming.quick_temp_cname)
+            else:
+                offset = ''
             for i, arg in enumerate(self.args):
-                code.putln("%s[%s] = %s;" % (
+                code.putln("%s[%s%s] = %s;" % (
                     self.result(),
                     i,
+                    offset,
                     arg.result()))
+            if self.mult_factor:
+                code.putln("}")
+                code.putln("}")
         elif self.type.is_struct:
             for arg, member in zip(self.args, self.type.scope.var_entries):
                 code.putln("%s.%s = %s;" % (

tests/run/arrayassign.pyx

@@ -9,6 +9,15 @@ def test_literal_list():
     a = [1,2,3,4,5]
     return (a[0], a[1], a[2], a[3], a[4])
 
+def test_literal_list_multiplied():
+    """
+    >>> test_literal_list_multiplied()
+    (1, 2, 1, 2, 1, 2)
+    """
+    cdef int a[6]
+    a = [1,2] * 3
+    return (a[0], a[1], a[2], a[3], a[4], a[5])
+
 def test_literal_list_slice_all():
     """
     >>> test_literal_list_slice_all()
@@ -297,3 +306,34 @@ def assign_to_wrong_csize():
     v[2] = 3
     d = v
     return d
+
+
+def assign_full_array_slice_to_array():
+    """
+    >>> assign_full_array_slice_to_array()
+    [1, 2, 3]
+    """
+    cdef int[3] x, y
+    x[0] = 1
+    x[1] = 2
+    x[2] = 3
+    y = x[:]
+    return y
+
+
+cdef class ArrayOwner:
+    cdef readonly int[3] array
+
+    def __init__(self, a, b, c):
+        self.array = (a, b, c)
+
+
+def assign_from_array_attribute():
+    """
+    >>> assign_from_array_attribute()
+    [1, 2, 3]
+    """
+    cdef int[3] v
+    a = ArrayOwner(1, 2, 3)
+    v = a.array[:]
+    return v