Re: Validate parameters to Lua functions

[Sean Conner <sean@...>]

It was thus said that the Great C++ RTMP Server once stated:
> Hello all,
> 
> I'm just trying the depth of the ocean with my finger here...
> 
> Is it somehow possible to validate the number/types of parameters for lua
> functions from C/C++? More details ...
> 
> 
> I already embedded lua as scripting engine in my project. What I do is to
> load the lua script, inspect the existence of certain lua functions in the
> script and if they exists I will call them when the time comes. Now, is it
> possible to also introspect/reflect on the number/types of parameters?
> 
> Some pseudo code:
> 
> if unable to load lua script
> 	return false
> 
> foreach functionName in functionsNamesList do
> 	if functionName doesn't exist //this works just fine
> 		continue

  Yes, this you can do.

> 	if functionName parameters count different from expected //maybe possible
> 		continue

  Nope.  All you can really do is see if the function exists.  It's up to
the function itself to check the paramters it gets.  

> 	if functionName parameters types different from expected //I bet that this is not possible....
> 		continue

  Nope.

> 	mark function as callable
> done


> Bottom line:

> Is there any lua api for further describe a LUA_TFUNCTION in greater
> detail? (parameters count, types, return type, etc)? Even if I have only
> parameters count is still better than nothing.

  Sorry, all you can do is see if it's a function, and when it's time to
call it, push what you think is the appropriate data onto the Lua stack and
call it.  

  -spc