a more consistent const syntax

[Rioshin an'Harthen]

"Chris Nicholson-Sauls" <ibisbasenji at gmail.com> kirjoitti viestissä 
news:f951kq$2fss$1 at digitalmars.com...
> Daniel919 wrote:
>> 3. const P func(P p) { ... }
>> reads like: func returns a const(P)
>
> Which is, indeed, a problem -- in that I agree.

I agree, as well. It reads like returning a const P.

>> const / invariant alone (without brackets) is an attribute and has no 
>> other meaning
>> further proposal: returned types in a bracket at the end:
>> 3. const func (P p) (P) { ... }
>> //templated syntax: const func!(T) (T p) (T) { ... }
>
> Uhm.  Ew.  No, seriously, I just could not possibly handle that; I would 
> keep thinking I saw templates where there aren't any.  Worse yet, for a 
> long time I'll see the '!(' and keep wondering how I could be 
> instantiating a template in that position, when its really a template 
> declaration.  T'is a naughty naughty thing to mix the two -- would give 
> both the compiler and the user headaches.  IMHO, its the 
> 'const'/'invariant' keyword on methods that needs to move -- not sure 
> where it should go, though.  What looks best down here?  ;)  (First 
> listing is the current state, for reference.)
>
> const P       vunc       (P p)       { ... }
>       P const func       (P p)       { ... }
>       P const:func       (P p)       { ... }
>       P const(func)      (P p)       { ... }
>       P       func const (P p)       { ... }
>       P       func:const (P p)       { ... }
>       P       func       (P p) const { ... }

Definitely the last one. It's immediately familiar to anyone with a C++ 
background, which I guess most of those coming to D has, and which I think 
are the people Walter is especially targetting. It also has the added bonus 
of not complicating method declaration grammar too much.

Same list, this time a const func returning a const return value:

const const(P) func (P p)
const(P) const func (P p)
const(P) const(func) (P p)
const(P) func const (P p)
const(P) func:const (P p)
const(P) func (P p) const

I definitely prefer the last one as the cleanest of these.