On Sep 20, 2009, at 6:32 PM, Greg Ewing wrote:
> Tan Swee Heng wrote:
>
>> Looking at app.c:
>>
>> // if expensive(i, 0) and expensive(i, 1): #
>> <<<<<<<<<<<<<<
>> if (__pyx_f_3app_expensive(__pyx_v_i, 0)) {
>> __pyx_t_2 = __pyx_f_3app_expensive(__pyx_v_i, 1);
>> } else {
>> __pyx_t_2 = __pyx_f_3app_expensive(__pyx_v_i, 0);
>> }
>
>> Q: For the short-circuit, would the right behaviour be to store the
>> result of the first evaluation in a temporary variable instead?
>
> I'd say so. Pyrex generates this:
>
> __pyx_5 = __pyx_f_3app_expensive(__pyx_v_i,0);
> if (__pyx_5) {
> __pyx_5 = __pyx_f_3app_expensive(__pyx_v_i,1);
> }
Yep, a bug for sure. Not just optimization, but if expensive() has
side effects than it disobeys Python semantics.
- Robert
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