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- Subject: RE: 5.0 changes question
- From: "Kevin Baca" <kbaca@...>
- Date: Thu, 6 Mar 2003 15:09:16 -0800
To get a named global use the macro:
lua_getglobal( L, var_name ); //declared in lua.h
As for accessing data as a hierarchy:
getValue( "a/b/c/d" )
I do something very similar (except mine looks like getRef( "a.b.c.d" ))
I use lua_ref, lua_getref, lua_unref (formerly functions, but now macros
lua_ref returns an integer identifier that you can later use to retrieve
a reference to the value that's currently on the top of the stack.
Call lua_getref( L, id ) to restore the value to the top of the stack.
To prevent lua from gc'ing the data, pass a non-zero as the 2nd arg to
lua_ref. Then, when you're finished with the ref, allow it to be gc'd
by calling lua_unref.
(Regarding the lock value - it looks like it's been deprecated. Anyone
know if this is this the case?)
Here's an example:
getRef( "a.b.c" ); is equivalent to:
Ref ref = getGlobalRef( "a" );
ref = ref.getRef( "b" );
ref = ref.getRef( "c" );
Using lua functions/macros:
lua_getglobal( L, "a" );
int i_ref_a = lua_ref( L, 1 ); //lua_ref pops top of stack
lua_getref( L, i_ref_a ); //restore value at "a" to top of
lua_pushstring( L, "b" );
lua_gettable( L, -1 );
int i_ref_b = lua_ref( L, 1 );
lua_getref( L, i_ref_b ); //restore value at "b" to top of
lua_pushstring( L, "c" );
lua_gettable( L, -1 ); //value stored at "a.b.c" is now
I hope I got that right.
> -----Original Message-----
> From: email@example.com
> [mailto:firstname.lastname@example.org] On Behalf Of Brian Hook
> Sent: Thursday, March 06, 2003 12:21 PM
> To: Multiple recipients of list
> Subject: Re: 5.0 changes question
> Actually what I'm doing is (I think) really simple, but since I have
> yet to seriously use Lua, I'm probably doing this all wrong, like
> bitflags =).
> I have an API call in my framework to "set the current table" so that
> I can then iterate over its members or find a member. Since I wasn't
> aware of a special table name for the globals, I would simply call
> lua_getglobals() if I wanted to select the global table.
> I had a fairly simple scanner that would then allow me to reference
> items in C code as if it were a directory structure, e.g. if I wanted
> to access foo.x.y I could specify it as:
> getValue( "/foo/x/y" );
> but if "foo" was already selected, I could also do:
> selectTable( "x" );
> getValue( "y" );
> So the important bit is that sometimes I wanted to set the global
> table as current, and other times I wanted to select a named table,
> depending on where I was trying to search the name space.
> Does this make sense?