Re: Eval a Lua expression

[Eugen-Andrei Gavriloaie <shiretu@...>]

On Apr 3, 2008, at 12:19 AM, Enrico Colombini wrote:

> Eugen-Andrei Gavriloaie wrote:
> > 3. I think the entire script will be executed entirely on each  
> > lua_evaluate_expression because of lua_pcall(L,0,1,0). This is not  
> > acceptable because I want to use this approach on other occasions.  
> > Here is ok, because we have to deal with a configuration file, but  
> > I will definitively have to deal with other types of Lua scripts  
> > that are not supposed to run over and over again. Am I right?
>
> If I understood correctly what you are looking for, have a look at  
> the "Generic call function" in PiL2 (25.4).
>
>  Enrico
Unfortunately this is not what I'm looking for. All I want is a way to  
evaluate an Lua expression (not calling a function). Something like

lua_evaluate_expression(L,"#applications")

where `applications` is a table of objects defined in the Lua file  
loaded previously. As you can see is not a function. I'd like to have  
a number
present on the Lua stack after returning from lua_evaluate_expression  
function.

Another example of a more complex expression:

lua_evaluate_expression(L,"some_lua_function_that_returns_a_string().. 
\" some other string\"")

where some_lua_function_that_returns_a_string is a Lua function that  
returns a string. On the result we append `some other string` string

The expression evaluation would be made on the lua_State context, so  
any expression can be made using all the things already present in the  
Lua script.