[pypy-commit] pypy can_cast: document some equivalences with numpy's C source

[rlamy]

Author: Ronan Lamy <ronan.lamy at gmail.com>
Branch: can_cast
Changeset: r77155:b37ce09bf154
Date: 2015-05-05 20:34 +0100
http://bitbucket.org/pypy/pypy/changeset/b37ce09bf154/

Log:	document some equivalences with numpy's C source

diff --git a/pypy/module/micronumpy/casting.py b/pypy/module/micronumpy/casting.py
--- a/pypy/module/micronumpy/casting.py
+++ b/pypy/module/micronumpy/casting.py
@@ -56,6 +56,7 @@
     UnicodeType.kind: 7, VoidType.kind: 8, ObjectType.kind: 9}
 
 def can_cast_type(space, origin, target, casting):
+    # equivalent to PyArray_CanCastTypeTo
     if casting == 'no':
         return origin.eq(space, target)
     elif casting == 'equiv':
@@ -72,6 +73,7 @@
         return origin.can_cast_to(target)
 
 def can_cast_array(space, w_from, target, casting):
+    # equivalent to PyArray_CanCastArrayTo
     origin = w_from.get_dtype()
     if w_from.is_scalar():
         return can_cast_scalar(
@@ -80,6 +82,7 @@
         return can_cast_type(space, origin, target, casting)
 
 def can_cast_scalar(space, from_type, value, target, casting):
+    # equivalent to CNumPy's can_cast_scalar_to
     if from_type == target or casting == 'unsafe':
         return True
     if not from_type.is_number() or casting in ('no', 'equiv'):
@@ -90,7 +93,7 @@
     if target.is_unsigned():
         dtypenum = altnum
     dtype = get_dtype_cache(space).dtypes_by_num[dtypenum]
-    return can_cast_type(space, dtype, target, casting)  # XXX: stub impl
+    return can_cast_type(space, dtype, target, casting)
 
 def is_scalar_w(space, w_arg):
     return (isinstance(w_arg, W_GenericBox) or
diff --git a/pypy/module/micronumpy/descriptor.py b/pypy/module/micronumpy/descriptor.py
--- a/pypy/module/micronumpy/descriptor.py
+++ b/pypy/module/micronumpy/descriptor.py
@@ -96,6 +96,7 @@
         return self.itemtype.box_complex(real, imag)
 
     def can_cast_to(self, other):
+        # equivalent to PyArray_CanCastTo
         result = self.itemtype.can_cast_to(other.itemtype)
         if result:
             if self.num == NPY.STRING:
diff --git a/pypy/module/micronumpy/types.py b/pypy/module/micronumpy/types.py
--- a/pypy/module/micronumpy/types.py
+++ b/pypy/module/micronumpy/types.py
@@ -135,6 +135,7 @@
         return rffi.sizeof(cls.T)
 
     def can_cast_to(self, other):
+        # equivalent to PyArray_CanCastSafely
         return casting_table[self.num][other.num]
 
 class Primitive(object):