This is probably a bad idea, but from my readings of the dmd source, I noticed some preprocessor defines that looked useful, along the lines of

#define CASES case A:case B: (etc)

I'd kinda like something similar in D, but a naive attempt with mixins doesn't work, e.g.

immutable string cases = "case 1: case 2:"; //my d2fu sucks

..

switch(x){
    mixin(cases);
      dosomething();
    default:
      dosomething();
}

Any ideas (not including concatenating cases with body of case)?

Ellery Newcomer wrote:
> This is probably a bad idea, but from my readings of the dmd source, I
> noticed some preprocessor defines that looked useful, along the lines of
> 
> #define CASES case A:case B: (etc)
> 
> I'd kinda like something similar in D, but a naive attempt with mixins
> doesn't work, e.g.
> 
> immutable string cases = "case 1: case 2:"; //my d2fu sucks
> 
> ..
> 
> switch(x){
>     mixin(cases);
>       dosomething();
>     default:
>       dosomething();
> }
> 
> Any ideas (not including concatenating cases with body of case)?

D supports case ranges:

switch(x) {
	case 1: .. case 10:
		doSomething();
	default:
		doSomething();
}

On Sat, Oct 10, 2009 at 8:45 PM, Ellery Newcomer <ellery-newcomer@utulsa.edu> wrote:
> This is probably a bad idea, but from my readings of the dmd source, I noticed some preprocessor defines that looked useful, along the lines of
>
> #define CASES case A:case B: (etc)
>
> I'd kinda like something similar in D, but a naive attempt with mixins doesn't work, e.g.
>
> immutable string cases = "case 1: case 2:"; //my d2fu sucks
>
> ..
>
> switch(x){
>    mixin(cases);
>      dosomething();
>    default:
>      dosomething();
> }
>
> Any ideas (not including concatenating cases with body of case)?

A single string mixin must consist of an entire, fully-formed statement, expression, or declaration (depending on where it's used). Case labels do not, on their own, count as a statement.

In addition, there is a bug that prevents you from string-mixing-in cases inside a switch. For some reason you have to mix in the entire switch statement.

Jarrett Billingsley wrote:
> On Sat, Oct 10, 2009 at 8:45 PM, Ellery Newcomer <ellery-newcomer@utulsa.edu> wrote:
>> This is probably a bad idea
> 
> A single string mixin must consist of an entire, fully-formed statement, expression, or declaration (depending on where it's used). Case labels do not, on their own, count as a statement.

Yeah they do. Ever wonder why you can do things like duff's device? Or

case 1:
case 2:

or

switch(x){
case 3:
}

> 
> In addition, there is a bug that prevents you from string-mixing-in cases inside a switch. For some reason you have to mix in the entire switch statement.


http://d.puremagic.com/issues/show_bug.cgi?id=1534

Hey! there's even a patch for it! And it works! Rainier, you da man!

Ellery Newcomer wrote:
> Jarrett Billingsley wrote:
>> On Sat, Oct 10, 2009 at 8:45 PM, Ellery Newcomer
>> <ellery-newcomer@utulsa.edu> wrote:
>>> This is probably a bad idea
>> A single string mixin must consist of an entire, fully-formed
>> statement, expression, or declaration (depending on where it's used).
>> Case labels do not, on their own, count as a statement.
> 
> Yeah they do. Ever wonder why you can do things like duff's device? Or

No, you can put multiple case labels together. A case "statement" is just a special category of label.

Christopher Wright wrote:
> Ellery Newcomer wrote:
>> Jarrett Billingsley wrote:
>>> On Sat, Oct 10, 2009 at 8:45 PM, Ellery Newcomer <ellery-newcomer@utulsa.edu> wrote:
>>>> This is probably a bad idea
>>> A single string mixin must consist of an entire, fully-formed statement, expression, or declaration (depending on where it's used). Case labels do not, on their own, count as a statement.
>>
>> Yeah they do. Ever wonder why you can do things like duff's device? Or
> 
> No, you can put multiple case labels together. A case "statement" is just a special category of label.

We're probably thinking on different levels. I'm down on the syntactic level. parseStatement(flag) can parse 'case x:' and nothing more if there's nothing more.