[CMake] CMake and Lua

[Peter Kümmel]

Ken Martin wrote:
> In VTK and ITK we did design a language independent toolkit and wrapped it
> into Tcl, Python, Java etc so we have done that and have a good feel for it.
> But for CMake I do not think it is a good idea for a couple reasons. One is
> fragmentation of the community/support. 

Every time this fear of fragmentation/forks.
Should we really care about it? I don't know.

> 
> The other is that a non-trivial portion of CMake is written in the scripting
> language ala the Modules directory. So supporting multiple languages becomes
> problematic. Most languages are not designed to mix with other languages. I
> doubt you can mix python and Lua and expect them to be able to access each
> other's variables out of the box. But with the Modules directory we either
> have to have a copy of each module for every possible scripting language, on
> the fly converters between any two scripting languages, or something like
> that to make it work. Trying to figure out how to manage the mixed
> CMakeScript/Lua variables by itself is already a bit of an issue to
> providing a Lua binding much less adding other languages on top of that.
> Hopefully that makes some sense :)

Yes, the existing modules are a problem. It makes no sense to support
multiple languages there.

Then it is only possible to provide a C++ interface so that all the
module stuff works "behind the scene" (behind the interface), using one
scripting language only. And if a new module should go upstream it
must use this language.

But all official-shipped modules could be made accessible through the
C++ interface, so that one still could call the generator functions
from a other language.


Anyway, I'm not sure any more if my initial idea was really that good.

Peter