Fio:LuaBinder

From Fio

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-	<font color=blue>''"Like a bridge over troubled water..."''</font> - Simon And Garfunkel	+	<font color=blue>''"Like a bridge over troubled water..."''</font> - Simon and Garfunkel
	<font color=red>still in ctoring</font>		<font color=red>still in ctoring</font>
	==Lua Binder==		==Lua Binder==
		+	Fio use [http://www.lua.org Lua] as scripting language to implement the game logic which include(in a broad sense):
		+	* UI design and switching
		+	* event handler
		+	* combat scheduler
		+	* npc behavior
		+
		+	All the logics/policies are build on the mechanims carried out by c++ classes which will do the real work of rendering, timing, event dispatching etc. This seperate is to make the game fully data driven - thru scripting the logic itself is taken as data which can be easily modified without the compile-link of the mechanism part(or the engine).
		+
		+	Lua has provided a bunch of API for "the host program to communicate with Lua". For each function call from lua into c++, we have to:
		+	* extract the arguments from lua stack;
		+	* check the argument/return value type;
		+	* call c++ function;
		+	* push the return value onto lua stack;
		+	* take care the return value life time.
		+
		+	thru Lua APIs.
		+
		+	As the number of classes need to be embedded into lua increases, these routine work will be a burden to write and maintain for each function call. There're quite a few [http://lua-users.org/wiki/LuaAddons binders] out there to make the embedding easier. In Fio we implement a home brew binder - LuaUtil.
	===Quick Tour===		===Quick Tour===

---

Revision as of 15:24, 15 September 2006

"Like a bridge over troubled water..." - Simon and Garfunkel

still in ctoring

Contents 1 Lua Binder 1.1 Quick Tour 1.2 The Lua Application Program Interface 1.3 Construct An Object 1.4 Method Invoking 1.4.1 from lua into c++ 1.4.2 from c++ into lua 1.5 Type Checking 1.5.1 LSP 1.6 Destruct & Object Lifetime in the 2 Worlds 1.7 Misc

Lua Binder

Fio use Lua as scripting language to implement the game logic which include(in a broad sense):

• UI design and switching
• event handler
• combat scheduler
• npc behavior

All the logics/policies are build on the mechanims carried out by c++ classes which will do the real work of rendering, timing, event dispatching etc. This seperate is to make the game fully data driven - thru scripting the logic itself is taken as data which can be easily modified without the compile-link of the mechanism part(or the engine).

Lua has provided a bunch of API for "the host program to communicate with Lua". For each function call from lua into c++, we have to:

• extract the arguments from lua stack;
• check the argument/return value type;
• call c++ function;
• push the return value onto lua stack;
• take care the return value life time.

thru Lua APIs.

As the number of classes need to be embedded into lua increases, these routine work will be a burden to write and maintain for each function call. There're quite a few binders out there to make the embedding easier. In Fio we implement a home brew binder - LuaUtil.

Quick Tour

The Lua Application Program Interface

Construct An Object

• normal
• lightweight

Method Invoking

• method wrap

from lua into c++

• traits
• Overload

from c++ into lua

callback?

Type Checking

LSP

Destruct & Object Lifetime in the 2 Worlds

Misc

• const
• panic
• utility functions