Adding Unicode operators to D

[Andrei Alexandrescu]

Bill Baxter wrote:
> On Mon, Oct 27, 2008 at 11:43 AM, Andrei Alexandrescu
> <SeeWebsiteForEmail at erdani.org> wrote:
>> Bill Baxter wrote:
>>> On Mon, Oct 27, 2008 at 9:04 AM, Andrei Alexandrescu
>>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>
>>>>>> What's the precedence of your user-defined in-fix operator?
>>>>>>
>>>>>> --bb
>>>>> Yup, I realized this myself as well. Seemed like such a great idea when
>>>>> I
>>>>> only thought of it for three seconds. :p
>>>> An operator could always be defined to have the same precedent as an
>>>> existing operator, which it has to specify.
>>> Walter said in a previous post a few days ago when I suggested it that
>>> that would kill D's easy parsability.
>>> You say no?  I'm no parser expert, so hard for me to say.
>> It can be done, but it's kinda involved. You define a grammar in which all
>> operators have the same precedence. Consequently you compile any expression
>> into a list of operands and operators. That makes the language parsable
>> without semanting info. Then the semantic stage transforms the list into a
>> tree. Cecil does that.
> 
> I see.  So the price you pay is that you defer more decisions till
> semantic stage.
> 
> I.e. "a b c d e" is allowed to parse into an amorphous list, then in
> the semantic pass you decide if 'b' and 'd' are actually legal
> operators or not.

Yah. Something tells me Walter won't embark on that soon.

Andrei