I enjoyed seeing the positive feedback on my idea. Here is some code to help you out:
//setPackage will create a new table with the same name as package_name//It will then set a metatable on the globals table to handle//getting values out of nonexisting keys and setting values for//nonexistant keys.void CLua::setPackage(const char* package_name){ m_packageName = (char*)package_name; lua_pushstring(m_L,package_name); //push the key name lua_rawget(m_L,LUA_GLOBALSINDEX); //Get the table in the globals table if (lua_type(m_L,-1) != LUA_TTABLE) //if it's not a table then it was not found, so create it { //create the table lua_newtable(m_L); //Create the new table on top of stack lua_pushstring(m_L,package_name); //Push the key name lua_pushvalue(m_L,-2); //Push the table lua_rawset(m_L,LUA_GLOBALSINDEX); //Create the element in the globals table to point to the new table } lua_pushstring(m_L,m_packageName); lua_rawget(m_L,LUA_GLOBALSINDEX); lua_newtable(m_L); //pushes the metatable onto the stack -3 lua_pushstring(m_L,"__newindex"); //pushes the key name for the metatable -2 lua_pushvalue(m_L,-3); //push the value of the new key on to the stack -1 lua_rawset(m_L,-3); //set the metatable event (metatable is now at the top of the stack) lua_pushstring(m_L,"__index"); lua_pushvalue(m_L,-3); //push the value of the new key on to the stack -1 lua_rawset(m_L,-3); //set the metatable event (metatable is now at the top of the stack) lua_setmetatable(m_L,LUA_GLOBALSINDEX); //Assign the metatable at the top of the stack to the GLOBALS table lua_pop(m_L,2); // Pop the package table and the new metatable}//createPackage will create a package table if one doesn't already//exist. It does not set the current package. Normally you will//not need to use this function but instead just call setPackage(...)//which will create and set the package.//This function is more of a synonym for "createTable(...)" which can be//useful to have.void CLua::createPackage(const char* package_name){ lua_pushstring(m_L,package_name); //push the key name lua_rawget(m_L,LUA_GLOBALSINDEX); //Get the table in the globals table if (lua_type(m_L,-1) != LUA_TTABLE) //if it's not a table then it was not found, so create it { //create the table lua_newtable(m_L); //Create the new table on top of stack lua_pushstring(m_L,package_name); //Push the key name lua_pushvalue(m_L,-2); //Push the table lua_rawset(m_L,LUA_GLOBALSINDEX); //Create the element in the globals table to point to the new table } lua_pop(m_L,1); //Clean up the stack}//Release package will set the specified package table to null and then also//remove the metatable from the GLOBALS table.void CLua::releasePackage(const char* package_name){ lua_pushnil(m_L); lua_setmetatable(m_L,LUA_GLOBALSINDEX); lua_pushstring(m_L,package_name); lua_pushnil(m_L); lua_settable(m_L,LUA_GLOBALSINDEX); }//Close package simply removes the metatable from the globals table.//The package table still remains and it is possible from any script//to do something like:// PackageName.myVariable = "hello";void CDysLua::closePackage(void){ lua_pushnil(m_L); lua_setmetatable(m_L,LUA_GLOBALSINDEX); }
Some key points about the above code.
I wrapped Lua using a class named CLua. CLua has the following member variables that need to be declared in the class:
lua_State* m_L; //Pointer to the Lua state
char* m_packageName; //Name of the current package
Trying to read the code is not too easy but hopefully the comments help.
Technically these functions could have been more elegantly implemented in native Lua code and then executed, but I like to think that implementing these functions in C is more efficient and fits better into the engine.
Along with functions for handling packages my wrapper also makes it easy to call Lua functions in scripts from C. It also makes it easy for a C function to easily open up tables and get values and then open tables inside tables, etc. Very fun features but I don't normally allow C functions to work directly with Lua variables but it's nice to know that feature is there
If you would like to see the code for the whole wrapper I would be more then willing to post it.
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[edited by - Computability on April 1, 2003 4:13:13 AM]
