typedef: what's it good for?

[Justin Johansson]

rmcguire Wrote:

> Justin Johansson <no at spam.com> wrote:
>  
> > Walter Bright Wrote:
> > 
> >> When I originally worked out ideas for D, there were many requests from 
> >> the C and C++ community for a 'strong' typedef, and so I put one in D. I 
> >> didn't think about it too much, just assumed that it was a good idea.
> >> 
> >> Now I'm not so sure. Maybe it should be removed for D2.
> >> 
> >> Does anyone use typedef's?
> >> 
> >> What do you use them for?
> >> 
> >> Do you need them?
> > 
> > Early on (2 months ago) when I was just getting into D I asked about typedefs 
> on this forum
> > and some discussion transpired.
> > 
> > http://www.digitalmars.com/d/archives/digitalmars/D/
> Is_typedef_an_alien_96658.html#N96658
> > 
> > (btw. There are a few responses from blasts from recent pasts in that thread.)
> > 
> > Anyway, grepping for typedef over my current "scripting-language in D" project 
> source
> > shows only old versions of my project using typedefs.  Accordingly it looks 
> like I have
> > since managed to convert *all* of my previous typedef incarnations to structs 
> so as to
> > take advantage of struct's support for static opCall so as to synthesize 
> "constructors"
> > (as well enabling use of struct methods).
> > 
> > Maybe I didn't know enough about D back then, but the big problem with D 
> typedefs
> > (for me at least) was there was no support for typedef constructors and code 
> otherwise
> > blotted with cast-to-typedef-type is yuk in my way of thinking.
> > 
> > I think there are only two sensible courses of action for D:  support typedef 
> constructors 
> > (and methods???) or remove 'em.  I'm not sure which option I prefer (is the 
> first even 
> > an option?)
> > 
> > Cheers
> > Justin Johansson
> > 
> > 
> 
> I like typedef for making header files for c libraries.
> For example, so that you can't just pass an int to a function expecting 
> an id.


Yep; I agree that's a good use for typedefs too .. but in the current D
formulation, you still need to use a cast don't you?