[phobos] phobos commit, revision 1737

[Andrei Alexandrescu]

On 07/08/2010 11:01 AM, Shin Fujishiro wrote:
> Michel Fortin<michel.fortin at michelf.com>  wrote:
>> Le 2010-07-08 à 8:13, Andrei Alexandrescu a écrit :
>>
>>> This is solid work! There's an opportunity here - it overlaps a LOT
>>> with std.variant.Algebraic.
>>
>>
>> Indeed. It's great. But why is the protection level set to 'package'?
>> Isn't it meant to be used outside of Phobos?
>
> I needed it to implement native codeset support in stdio.  I just went
> conservative for adding a public stuff that people might not use...

Cool, looking forward to seeing the result. For all I know Ruby was very 
successful in Japan because it had support for the Japanese character 
sets from day one.

>> One thing I've missed about Algebraic is the ability to switch on the
>> type, somewhat like this:
>>
>> 	Algebraic!(A, B, C) x;
>> 	switch (x.type) {
>> 		case x.typecode!A:
>> 		case x.typecode!B:
>> 		case x.typecode!C:
>> 			...
>> 	}
>>
>> Seems like this would be easy by switching on Any's _duckID, but this
>> facility isn't exposed (it's all private).
>
> It's nice.  I'll add it!
>
> switch (x.Algebraic.type) {
>      case x.Algebraic.typeCode!A:
>      case x.Algebraic.typeCode!B:
>     ...
>      default:
> }

I don't think that's very useful because you need to follow each case 
with a peek() or something. I was thinking it would be great to define a 
dispatcher a la Sean's receive():

x.Algebraic.dispatch(
     (A obj) {  writeln("saw an A"); },
     (B obj) {  writeln("saw a B"); },
     ...
);

Such a dispatch function could come in two flavors: strict and non-strict.


Andrei