Re: Lua language extension for complex number and vector values

[Luiz Henrique de Figueiredo <lhf@...>]

> > The only way out that I can see is to use an explicit block as in say
> > 	complex.enter()
> > 	complex.eval(a * exp(i*z) + b, a*b+z)
> > 	complex.exit()
>
> Would you care to explain how you can get the above to work?  I thought maybe you mean that inside the block, everything is temporary, but I'm not sure that would work.

Yes, I mean that inside the block, everything is temporary and stored
in static vars in C. The complex C library would have 256 static
pointers to hold temporary userdata, say allocated at the start in
luaopen_complex. complex.enter would start using them instead of
allocating new ones. The expressions in complex.eval would be evaluated
as usual by Lua, but using the temporary userdata. However, complex.eval
would duplicate the userdata corresponding to its arguments, using real
allocation, so that they can be returned. I should have written
	val1, val2 = complex.eval(a * exp(i*z) + b, a*b+z)

complex.exit would clear the internal counter. Perhaps it is not needed
and this can be done in complex.eval, but it seems clear to explicitly
bracket blocks.