Re: Lua binding: How to implement C enum

[Marc Balmer <marc@...>]

Am 15.12.11 15:34, schrieb Ezequiel García:
> Hi!
> I am working on a Lua binding for a library that makes extensive use
> of enums to pass on flags, capabilities, and such. Like this:
> 
> typedef enum {
>      UNKNOWN    = 0x00000000,
>      FRONTONLY  = 0x00000001,      
>      BACKVIDEO  = 0x00000002,      
>      BACKSYSTEM = 0x00000004,
>      TRIPLE     = 0x00000008,
>      WINDOWS    = 0x00000010
> } BufferMode;
> 
> So I would like to know the community opinion on this: How to implement this kind of C enums?
> 
> So far, my solution is this: translate each symbol of the like 'UNKNOWN'
> into a Lua numeric global variable. The global is not mandatory, for I could
> pushed it into the module itself. But, in that case, I would have to type:
> 
>   module_name.UNKNOWN
> 
> each time and I am too lazy for that.
> 
> The numeric part comes because I want to add flags and such, like this:
> 
>   buffermode = TRIPLE + WINDOWS
> 
> Fortunately I don't need to OR, and if needed one could use any bit library.
> The cons of this solution is not having any "type checking" or somekind
> of "type enforcement" since variables or just variables, I could even mispell
> and end up with a nil value. 
> The pro of the solution is (at least to me): ease of implementation, ease of usage.
> 
> So, what do you think?

I do it more or less the same way, and until now I did not run into
problems.

> 
> Thanks a lot,
> Ezequiel.
> 
>