Re: [Swig-user] Get C++ constants in LUA

[Mark G. <ma...@go...>]

> 
> We recently upgraded SWIG from version 1.1.31 to 1.1.36 and
> have hit a small problem (probably nothing, just can't
> figure it out). C++ constant variables used to be SWIGed,
> and accessible through module.ConstName_get() from a LUA
> script in the oldest of the two versions. However, there
> doesn't seem to be a function to obtain the variable
> value in the newest version. I have tried to obtain the
> value with in different ways, but have not been able to.
> It's also the same for every variable contained in the
> swig_variables array. Thanks for enlightening me as to how I
> should procede to get the constant value.
> 
> St?fan Beauchamp

Hello St?fan,
The quick answer is I removed it. 
When I first wrote the Lua bindings.

const Foo ConstName;

Would produce a function module.ConstName_get(), so in Lua you could do.

a=module.ConstName_get()
-- or
b=module.ConstName

However sometime back (probably about 1.3.33 or so), I discovered how to stop adding the module.ConstName_get() and just use module.ConstName

So, you can just use module.ConstName instead, which is IMHO much nicer. The following code will work:
a=module.ConstName
someFunction(module.ConstName)
module.ConstName:someMethod(1,2,3)
This code will not
module.ConstName=something
It will generate an error ("this variable is immutable")

If you _really_ wanted the function back the following code would add it in.

%native(ConstName_get) int _wrap_ConstName_get(luaState*);

Hope this clarifies the matter.

PS. For shared variables, the get and set functions have vanished for the same reasons.

Hope this helps,
Mark