Short list with things to finish for D2

[Bill Baxter]

On Thu, Nov 19, 2009 at 1:26 PM, Walter Bright
<newshound1 at digitalmars.com> wrote:
> aarti_pl wrote:
>>
>> I know that quite a few people here doesn't like to allow users to define
>> their own operators, because it might obfuscate code. But it doesn't have to
>> be like this. Someone here already mentioned here that it is not real
>> problem for programs in C++. Good libraries don't abuse this functionality.
>
> The problem with user defined operators is:
>
>  1. User defined tokens - mixes up lexing with semantic analysis
>
>  2. User defined syntax - mixes up parsing with semantic analysis
>
> and then we're in C++ land :-(
>
> Unless such have a unique grammar that can be lexed and parsed:
>
>    a :string: b
>
> where string is the user defined name, so you can do things like:
>
>    a :^^: b
>
> and define your own pow operator. The problem with this approach is the
> sheer ugliness of it.

You also have to wedge precedence in there somehow.
Maybe instead of :string: you use +string+ or *string* and the
first/last character tells the precedence.

Oh wait, downs already has code that does this.  The question, I
think, is how to make it reasonably fast and less cumbersome to
declare.
Though I'm not sure it's really worth the effort.

--bb