研究这块东西的起因
既不是为了当成游戏里的脚本用；也不是为了用lua调用原生控件实现跨平台；只是为了保持和我司Android端的部分关键算法一致，所以把这部分代码写成了lua。
起初查资料，会有wax、cocos2d之类的内容，但是我们并需要这么“重量级”的东西，就一个lua文件，所以最后决定用C和lua交互，自己写。
目前这部分东西已经在线上跑了1年+，至少是可以用的。
分享一部分有关键代码和最初开发思路。
达到目标
1.正确传参
- 基础数据格式：BOOL、Number、NSString
- NSArray、NSDictonary等复杂参数传入
2.实现返回数据
- 基础数据格式：BOOL、Number、NSString
- NSArray、NSDictonary等复杂参数返回值
添加Lua
下载Lua，将src目录改名为lua，拖进项目。删除掉lua.c和luac.c
这个时候编译是成功的。
我使用的版本是Lua 5.1.4，当初为了与安卓团队的第三方jar包版本保持一致。新版本应该语法有一些改变。
Lua这边有用的东西
这是我在调试lua的table用的print，因为会用到时间戳，所以有个地方判断了数字，lua里的print是不能输出table的格式，可比NSLog不方便多了。于是在网上搜索了下资料，最后对应我们自己的需求做了一点点调整，原网页已经找不回来了，没法放在参考链接里了。
tab = " "
dateOutput = true
function print_r(t)
print_table(t, 0)
end
function print_table(t, i)
local indent ="" -- i缩进，当前调用缩进
for j = 0, i do
indent = indent .. tab
end
for k, v in pairs(t) do
if (type(v) == "table") then -- type(v) 当前类型时否table 如果是，则需要递归，
local key = ""
if type(k) ~= "number" then
key = k
end
print(indent ..key, "{")
print_table(v, i + 1) -- 递归调用
print(indent .. "}")
else -- 否则直接输出当前值
if (dateOutput and type(v) == "number" and v > 100000) then
v = os.date("%x", v)
end
if type(v)=="boolean" then
v=(v and "true") or "false"
end
print(indent .. k .. "=" .. v..",")
end
end
end
Lua测试文件
- 简单测试，在lua端成功print出东西
function test()
print("成功啦!")
end
- 向lua传值
function simpleParam(value)
print(value)
end
- 从lua拿值
function simpleParam()
return 5,9
end
- 向lua传NSArray或者NSDictionarys
function complexParam(value)
print_r(value)
end
- 从lua拿值
function complexParam()
local s1 = {name = "a", age = 20}
local s2 = {name = "b", age = 19}
return {s1, s2}
end
OC生成Lua的state
state = luaL_newstate();
luaL_openlibs(state);
lua_settop(state, 0);
NSString *luaFilePath = [[NSBundle mainBundle] pathForResource:@"file" ofType:@"lua"];
NSString *luaContent = [NSString stringWithContentsOfFile:luaFilePath
encoding:NSUTF8StringEncoding
error:nil];
int err;
if (luaContent == nil || [luaContent isEqualToString: @""]) {
NSLog(@"Lua_State initial fail，lua file is nil");
}else {
err = luaL_loadstring(state, [luaContent cStringUsingEncoding: NSUTF8StringEncoding]);
if (0 != err) {
luaL_error(state, "cannot compile the lua file: %s",
lua_tostring(state, -1));
return;
}
err = lua_pcall(state, 0, 0, 0);
if (0 != err) {
luaL_error(state, "cannot run the lua file: %s",
lua_tostring(state, -1));
return;
}
NSLog(@"Lua_state initial success");
}
OC调用
- 简单测试，在lua端成功print出东西
lua_State* state = [[LuaBinding shareBinding] state];
lua_getglobal(state,"test");
lua_pcall(state, 0, 0, 0);
- 向lua传值
lua_State* state = [[LuaBinding shareBinding] state];
lua_getglobal(state,"simpleParam");
lua_pushnumber(state, 7);
lua_pcall(state, 1, 0, 0);
- 从lua拿值
lua_State* state = [[LuaBinding shareBinding] state];
lua_getglobal(state,"simpleParam");
lua_pcall(state, 0, 2, 0);
NSInteger result1 = (NSInteger)lua_tointeger(state, -1);
lua_pop(state, 1);
NSInteger result2 = (NSInteger)lua_tointeger(state, -1);
lua_pop(state, 1);
NSLog(@"%ld,%ld", (long)result1,(long)result2);
- 向lua传NSArray或者NSDictionarys
这里可没有可以直接用的lua_pushXXXX的东西来用了，我现在的处理方式是自己判断类型，做后pushNumber、pushString等等。听说jar包那边的是用lua的userdata之类的东西，我并没有研究了，因为当时开发需求赶，并且我对lua并没有太多兴趣...
虽然我没有userdata，但是最近一次测试，我们传了1外3M的数据文件进去处理，我们只用了0.1s，而安卓的第三方库用了10s...
我唯一担心的是，内存这块的东西，因为确实对C和lua并不熟悉
代码参考
- (void)pushObject:(id)object state:(lua_State *)state{
unsigned int outCount = (unsigned int)[object count];
if ([object isKindOfClass:[NSDictionary class]]) {
lua_createtable(state, outCount, 0);
for (NSString* key in object) {
id value = object[key];
lua_pushstring(state, [key cStringUsingEncoding: NSUTF8StringEncoding]);
if ([value isKindOfClass: [NSString class]]) {
lua_pushstring(state, [value cStringUsingEncoding: NSUTF8StringEncoding]);
} else if([value isKindOfClass: [NSNumber class]]) {
lua_pushnumber(state, [value doubleValue]);
} else {
[self pushObject:value state:state];
}
lua_rawset(state, -3);
}
} else {
lua_createtable(state, outCount, 0);
for (int i = 0; i < outCount; i++) {
lua_pushinteger(state, i + 1);
id element = object[i];
if ([element isKindOfClass: [NSString class]]) {
lua_pushstring(state, [element cStringUsingEncoding: NSUTF8StringEncoding]);
} else if([element isKindOfClass: [NSNumber class]]) {
lua_pushnumber(state, [element doubleValue]);
} else {
[self pushObject:element state:state];
}
lua_settable(state, -3);
}
}
}
- 从lua拿NSArray或者NSDictionarys
与第4条一样，没有现成的lua_toXXXX可用。
参考代码
- (id)readLuaTable:(lua_State *)state{
int index = lua_gettop(state);
lua_pushnil(state);
id info = nil;
while(lua_next(state, index) != 0)
{
if (info == nil) {
if (lua_type(state, -2) == LUA_TNUMBER) {
info = [NSMutableArray array];
}else {
info = [NSMutableDictionary dictionary];
}
}
if(lua_isnumber(state, -1)){
double value = lua_tonumber(state, -1);
if ([info isKindOfClass: [NSMutableDictionary class]]) {
[info setObject: @(value)
forKey: [NSString stringWithUTF8String: lua_tostring(state, -2)]];
}else if ([info isKindOfClass: [NSMutableArray class]]) {
[info addObject: @(value)];
}
}
else if(lua_isstring(state, -1)){
const char* value = lua_tostring(state, -1);
if ([info isKindOfClass: [NSMutableDictionary class]]) {
[info setObject: [NSString stringWithUTF8String: value]
forKey: [NSString stringWithUTF8String: lua_tostring(state, -2)]];
}else if ([info isKindOfClass: [NSMutableArray class]]) {
[info addObject: [NSString stringWithUTF8String: value]];
}
}
else if(lua_isboolean(state, -1)){
BOOL value = lua_toboolean(state, -1);
if ([info isKindOfClass: [NSMutableDictionary class]]) {
[info setObject: @(value)
forKey: [NSString stringWithUTF8String: lua_tostring(state, -2)]];
}else if ([info isKindOfClass: [NSMutableArray class]]) {
[info addObject: @(value)];
}
}
else if(lua_istable(state, -1)){
id value = [self readLuaTable: state];
if (value != nil && [info isKindOfClass: [NSMutableDictionary class]]) {
[info setObject: value
forKey: [NSString stringWithUTF8String: lua_tostring(state, -2)]];
}else if (value != nil && [info isKindOfClass: [NSMutableArray class]]) {
[info addObject: value];
}
}else {
NSLog(@"未识别lua的类型");
}
lua_pop(state, 1);
}
return info;
}
参考
http://blog.stokedsoftware.com/blog/2012/02/04/scripting-ios-games-with-lua/
