Added classes

src/bindings/classes.c

@@ -0,0 +1,107 @@
+#include "classes.h"
+#include "../lu5_logger.h"
+
+#include <lauxlib.h>
+
+/**
+ * Get the number of arguments based on a function declaration 
+ * 
+ * @param L The lua state
+ *
+ * @return int The number of arguments
+ */
+static int lu5_get_declaration_argc(lua_State *L, int index) {
+	// Get arg count from declaration
+	lua_getglobal(L, "debug");
+
+	// Push debug.getinfo
+	lua_getfield(L, -1, "getinfo");
+	lua_pushvalue(L, index);
+
+	// Push the what string
+	lua_pushstring(L, "u");
+
+	// Call debug.getinfo(func, "u")
+	lua_call(L, 2, 1);
+
+	// Get nparams from the result
+	lua_getfield(L, -1, "nparams");
+
+	// Get argc
+	int result = lua_tointeger(L, -1);
+
+	// Cleanup stack
+	lua_pop(L, 3);
+
+	return result;
+}
+
+static int lu5_call(lua_State *L) {
+	// Create the instance table
+	lua_newtable(L); 
+
+	// Set the class table as the metatable of the instance
+	lua_pushvalue(L, 1); 
+	lua_setmetatable(L, -2);
+
+	// Get the 'init' method from the class table
+	lua_getfield(L, 1, "init");
+	if (!lua_isfunction(L, -1)) {
+		luaL_error(L, "class does not have an 'init' method");
+		return 0;
+	}
+
+	// Check if arg count matches
+	int declaration_argc = lu5_get_declaration_argc(L, -3);
+	int caller_argc = lua_gettop(L)-2;
+
+	if (declaration_argc != caller_argc) {
+		LU5_ERROR("Expected %i arguments in constructor, recieved %i", declaration_argc-1, caller_argc-1);
+		lua_pushvalue(L, -1);
+		return 1;
+	}
+
+	// Prepare to call 'init'
+	lua_pushvalue(L, -2);  // Push the instance (newly created table)
+
+	// Push all arguments from the into the 'init' call
+	for (int i = 2; i <= declaration_argc; i++) {
+		lua_pushinteger(L, lua_tointeger(L, i));
+	}
+
+	// Call 'init'
+	if (lua_pcall(L, declaration_argc, 1, 0) != LUA_OK) {
+		luaL_error(L, lua_tostring(L, -1));
+		lua_pop(L, 1);  
+		return 0;
+	}
+
+	// Return the new instance
+	return 1;
+}
+
+int lu5_class(lua_State *L) {
+	// Get the class name
+	const char *name = luaL_checkstring(L, 1);
+
+	// Create class table
+	lua_newtable(L);
+
+	// Set class name in class table for possible use
+	lua_pushstring(L, name);
+	lua_setfield(L, -2, "__name");
+
+	// Set __index to itself
+	lua_pushvalue(L, -1);
+	lua_setfield(L, -2, "__index");
+
+	// Set new metamethod in the metatable
+	lua_newtable(L);
+	lua_pushcfunction(L, lu5_call);
+	lua_setfield(L, -3, "new");
+
+	// set the new table as its own metatable
+	lua_setmetatable(L, -2);
+
+	return 1; // Return new class
+}

src/bindings/classes.h

@@ -0,0 +1,41 @@
+#ifndef _LU5_CLASSES_H_
+#define _LU5_CLASSES_H_
+#include <lua.h>
+/**
+ * Create a metatable
+ * 
+ * @param name The class name
+ *
+ * @example
+ * local Player = class('Player');
+ *
+ * function Player:init(x, y)
+ *   self.x = x;
+ *   self.y = y;
+ *   return self;
+ * end
+ *
+ * function Player:draw()
+ *   circle(self.x, self.y, 16);
+ * end
+ *
+ *
+ * -- Create 2 players and draw them
+ * local p1 = Player:new(100, 200);
+ * local p2 = Player:new(300, 200);
+ *
+ * function setup()
+ *   createWindow(400, 400);
+ * end
+ * 
+ * function draw()
+ *   background(51);
+ *
+ *   p1:draw();
+ *   p2:draw();
+ * end
+ * @example
+ */
+int lu5_class(lua_State *L);
+
+#endif

src/lu5_bindings.c

@@ -7,6 +7,7 @@
 #include "bindings/shapes.h"
 #include "bindings/lu5_math.h"
 #include "bindings/loaders.h"
+#include "bindings/classes.h"
 
 #include "lu5_defs.h"
 
@@ -40,6 +41,8 @@ void lu5_register_symbols(lua_State *L)
 
 	LUA_ADD_FUNCTION(L, print);
 
+	LUA_ADD_FUNCTION_BY_NAME(L, "class", lu5_class);
+
 	LUA_ADD_FUNCTION(L, createWindow);
 	LUA_ADD_FUNCTION(L, background);
 	LUA_ADD_FUNCTION(L, frameRate);