Call function by its string name

[John Colvin]

On Saturday, 19 October 2013 at 17:17:47 UTC, aldanor wrote:
> On Saturday, 19 October 2013 at 16:56:50 UTC, John Colvin wrote:
>> On Saturday, 19 October 2013 at 16:33:11 UTC, aldanor wrote:
>>> I was wondering if it was possible to call D functions by 
>>> their names (strings that are not known at compile time) and 
>>> couldn't find the answer anywhere in the documentation. Kinda 
>>> like we can instantiate objects with Object.factory, would it 
>>> be possible to somehow do the same with module-level 
>>> functions? Or maybe with non-static class methods?
>>
>> You could make an associative array of function pointers with 
>> strings as keys. Probably not the best solution but it should 
>> work.
>
> Thanks for the reply, this is something I thought about of 
> course. But what if I have hundreds of functions to dispatch 
> to? The current (C) implementation does exactly that, 
> autogenerates a sort of an associative array, but that's very 
> ugly and requires an extra preprocessing step.
>
> I was thinking runtime reflections can help do this, but I'm 
> not quite sure where to start (and there is also the 
> performance question).

No matter what happens, if you want to take a runtime string and 
work out what function it corresponds to then you're going to 
have to use some sort of string matching.

Unless you have a very specific function name format then a hash 
is probably the fastest way to do this, especially in the case of 
hundreds of functions.

D's compile-time reflection could probably make building the 
associative array neat and easy.