[Python-Dev] Dictionary evaluation order

[Gustavo Niemeyer]

I was just looking at the bug

    [#448679] Left to right

It mentions that code like that

    {f1():f2(), f3():f4()}

Will call these functions in the order f2, f1, f4, f3. What should we
do about it? Tim mentions that "When [Tim] asked Guido about that
some years ago, he agreed it was a bug.". Is it too late to fix it, or
is it still a desirable fix?

The fix should be as easy as that:

diff -u -r2.264 compile.c
--- Python/compile.c    3 Oct 2002 09:50:47 -0000       2.264
+++ Python/compile.c    26 Nov 2002 04:02:27 -0000
@@ -1527,9 +1527,9 @@
                   It wants the stack to look like (value) (dict) (key) */
                com_addbyte(c, DUP_TOP);
                com_push(c, 1);
-               com_node(c, CHILD(n, i+2)); /* value */
-               com_addbyte(c, ROT_TWO);
                com_node(c, CHILD(n, i)); /* key */
+               com_node(c, CHILD(n, i+2)); /* value */
+               com_addbyte(c, ROT_THREE);
                com_addbyte(c, STORE_SUBSCR);
                com_pop(c, 3);
        }

(compiler module should be fixed as well, as it mimicks that behavior)

So I belive it just a matter of deciding what should be done.

-- 
Gustavo Niemeyer

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