Replacing the comma operator

[Andrei Alexandrescu]

Stewart Gordon wrote:
> Jarrett Billingsley wrote:
> <snip>
>> For two, what problem did Andrei point out?  Order of evaluation of
>> function arguments?  On the contrary, he said "now that order of
>> evaluation will be defined to be left-to-right in D, the semantics
>> would be quite the same".  Your code is what you'd have to use in D1,
>> but in D2, the simpler version would suffice.
> 
> What do you understand by the combination of "now" and "will be"?
> 
> I understood that he was speaking either sarcastically or hypothetically.
> 
> Or can you find any official statement of this change, let alone a 
> rationale for it?

No, sorry. Usually I strive to be precise, but this time I just wasn't. 
The plan is to define order of evaluation to be lexical order. Somehow I 
can't convince Walter that that means assignment too!

e1[e2] = e3;

means:

1. Evaluate e1

2. Evaluate e2

3. Evaluate []

4. Evaluate e3

5. Evaluate assignment.

Walter wants:

1. Evaluate e3. Why in the world, I have no idea.

2, 3. Evaluate e1 and e2, I'm not sure in which order he thinks is right

4. Evaluate []

4. Evaluate =

Lexical order rules. Lexical order dammit!

Walter and I see eye to eye probably 95% of the time, which has two 
disadvantages: (a) everybody here thinks one is influencing the other 
when in fact most of the time we arrive at the same conclusion from very 
different paths, (b) the remaining 5% are disconcerting. This is one of 
those cases.


Andrei