Arguments for a module loader
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- Subject: Arguments for a module loader
- From: Matthias Kluwe <mkluwe@...>
- Date: Tue, 7 Aug 2012 16:59:51 +0200
Hi!
I must admit that I don't really understand the documentation of
require (as given by
http://www.lua.org/manual/5.2/manual.html#pdf-require).
After reading it several times I gave up and decided to help myself by
some example code. I wrote the following simple module:
#include <stdio.h>
#include <lua5.2/lua.h>
int luaopen_mod( lua_State *L ) {
printf( "stack size : %d\n", lua_gettop( L ) );
printf( "typename 1: %s\n", lua_typename( L, 1 ) );
printf( "typename 2: %s\n", lua_typename( L, 2 ) );
printf( "value 1: %d\n", lua_toboolean( L, 1 ) );
printf( "isuserdata 2: %d\n", lua_isuserdata( L, 2 ) );
printf( "isstring 2: %d\n", lua_isstring( L, 2 ) );
printf( "value 2: %s\n", lua_tolstring( L, 2, 0 ) );
lua_newtable( L );
return 1;
}
and compiled it with gcc -shared -o mod.so mod.c.
When called by `require 'mod'` the output is
stack size : 2
typename 1: boolean
typename 2: userdata
value 1: 1
isuserdata 2: 0
isstring 2: 1
value 2: ./mod.so
Ok, two arguments as mentioned in the manual. But:
On position 2 I've got a userdata which is none according to
isuserdata(). This argument may be the modname. I didn't understand
what this is exactly, but somehow I expected 'mod' rather than
'./mod.so'.
On position 1 I've got a boolean true, which means 'the loader does
not return a non-nil value and has not assigned any value to
package.loaded[modname]'? What's the "loader" in this case exactly?
Regards,
Matthias