Programming on OSX

[Mike Parker]

On 1/1/2012 7:38 PM, Joel Christensen wrote:
> On 01-Jan-12 3:27 AM, Jacob Carlborg wrote:
>> On 2011-12-31 00:50, Joel Christensen wrote:
>>> I've got an Mac with OSX. But I have a few problems with using it
>>> with D.
>>>
>>> 1. I haven't got any media programming going.
>>
>> Could you please elaborate. Derelict is a library that contains bindings
>> for OpenGL, OpenAL, SDL and DevIL among others.
>
> Thanks for replying Jacob.
>
> I looked up Derelict and it seem to say Derelict's SDL didn't work with
> OSX yet. I haven't done much digging though. I'm more interested in
> Allegro5 working with OSX, there's one Allegro library that works with
> Windows and Linux, but not OSX.

DerelictSDL works fine on Mac. The Derelict 2 branch also has a binding 
for Allegro 5 which should work on Mac after a minor update. I'm using 
the DerelictAllegro binding for a couple of projects right now.


>
> On a bit different note. What's the differences with a library, a
> wrapper, and a binding?
>

A /library/ is a collection of resuable code. SDL and Allegro5 are 
libraries.

A /binding/ is a kind of library that provides a bridge to use a library 
written in a language different from what it was written with.The 
details of how that happens depends entirely on the language the binding 
is written for. For example, in Java, bindings to C or C++ libraries are 
effectively wrappers, because of the way the bindings must be written. 
But in D, because it is compatible with the C ABI, bindings can be 
one-to-one. Meaning, as long as a C function or type has a declaration 
in D, it can be used in D. Derelict is an example of a binding (well, 
several bindings).

A /wrapper/ is a kind of library that encloses an existing library in a 
different interface. Usually, it's a free function interface being 
wrapped in an object-oriented interface. For example, Allegro is written 
in C. A D (or C++) wrapper might be written to give it an 
object-oriented interface, as long as it had a binding to work with. In 
other words, it allows you to do this (:

Bitmap bmp = new Bitmap();

instead of this:

ALLEGRO_BITMAP* bmp = al_create_bmp(...);

So to use a wrapper of a C library in D, you would have this setup:

C Library -> D binding library (allows C functions to be called in D) -> 
D Wrapper library (giving an object oriented interface) -> application

Of course, the wrapper could also be the binding.

Personally, I think wrappers are a waste of time, but some people prefer 
them to using a C API directly.