#include "lua-properties.h" static void register_cfuncs(lua_State* L, const luaL_Reg reg_table[]) { const luaL_Reg* reg; for (reg = reg_table; reg->name; reg++) { lua_pushstring(L, reg->name); lua_pushcfunction(L, reg->func); lua_rawset(L, -3); } } static int properties_index (lua_State *L) { lua_pushvalue(L, 2); /* push the key */ lua_rawget(L, lua_upvalueindex(1)); /* lookup into methods' table (upvalue) */ if (lua_isnil(L, -1)) /* if the method does not exists */ { lua_pushvalue(L, 2); /* push the key */ lua_rawget(L, lua_upvalueindex(2)); /* lookup into getters table (upvalue) */ if (lua_isnil(L, -1)) /* if getter function does not exists */ return 1; /* return nil */ /* the getter exists: */ lua_pushvalue(L, 1); /* push the object itself (plot) */ lua_call(L, 1, 1); /* call the getter and return the result */ return 1; } /* the method exists. We return it (a function). */ return 1; } static int properties_newindex (lua_State *L) { lua_pushvalue(L, 2); /* push the key */ lua_rawget(L, lua_upvalueindex(1)); /* lookup into setters table (upvalue) */ if (!lua_isnil(L, -1)) /* if setter function does exists */ { lua_pushvalue(L, 1); /* push the object itself (plot) */ lua_pushvalue(L, 3); /* push the value for the setter */ /* call the setter function with the plot and value as arguments */ lua_call(L, 2, 0); return 0; } return 0; } /* Assume that we have on top of the stack a table and add a __index and __newindex function to access the methods and properties getters. Leave the table on top of the stack. */ void register_properties_index(lua_State* L, const luaL_Reg methods[], const luaL_Reg getters[], const luaL_Reg setters[]) { lua_pushstring(L, "__index"); lua_newtable(L); /* create a new table to hold the methods */ register_cfuncs(L, methods); /* register all the methods into the table */ lua_newtable(L); /* create a new table to hold the getters */ register_cfuncs(L, getters); /* register all the getters into the table */ /* create a closure with the methods and getters tables as upvalues */ lua_pushcclosure(L, properties_index, 2); lua_rawset(L, -3); /* bind the newly created closure to __index */ lua_pushstring(L, "__newindex"); lua_newtable(L); /* create a new table to hold the setters */ register_cfuncs(L, setters); /* register all the setters into the table */ /* create a closure with the setters' table as upvalue */ lua_pushcclosure(L, properties_newindex, 1); lua_rawset(L, -3); /* bind the newly created closure to __newindex */ }