[Python-3000] Betas today - I hope

[Georg Brandl]

Nick Coghlan schrieb:

> 2. Method lookup MAY bypass __getattribute__, shadowing the attribute in 
> the instance dictionary MAY have ill effects. (slots such as __enter__ 
> and __exit__ that are looked up via normal attribute lookup in CPython 
> will fit into this category)

I would argue that the __enter__ and __exit__ behavior should be changed too.
The reason for the current behavior is this:

   2           0 LOAD_GLOBAL              0 (a)
               3 DUP_TOP
               4 LOAD_ATTR                1 (__exit__)
               7 STORE_FAST               0 (_[1])
              10 LOAD_ATTR                2 (__enter__)
              13 CALL_FUNCTION            0
              16 STORE_FAST               1 (_[2])
              19 SETUP_FINALLY           18 (to 40)

IOW, when "with" is compiled, the attributes are retrieved using bytecode.
It wouldn't be hard to have a WITH_SETUP opcode (along with the already
existing WITH_CLEANUP) that would make the bytecode read like:

   2           0 LOAD_GLOBAL              0 (a)
               3 WITH_SETUP               0 (_[1])
               6 STORE_FAST               1 (_[2])
               9 SETUP_FINALLY           18 (to 40)

Georg