[Lua] try catch实现

参考了https://blog.csdn.net/waruqi/article/details/53649634这里的代码，但实际使用时还有些问题，修改后在此记录一下。

-- 异常捕获
function try(block)
    -- get the try function
    local try = block[1]
    assert(try)

    -- get catch and finally functions
    local funcs = block[2]

    -- try to call it
    local ok, errors = xpcall(try, debug.traceback)
    if not ok then
        -- run the catch function
        if funcs and funcs.catch then
            funcs.catch(errors)
        end
    end

    -- run the finally function
    if funcs and funcs.finally then
        funcs.finally(ok, errors)
    end

    -- ok?
    if ok then
        return errors
    end
end

function test()
try
    {
        function ()
            xxx()
        end,
        {
            -- 发生异常后，被执行
            catch = function (errors)
                print("LUA Exception : " .. errors)
            end,

            finally = function (ok, errors)
                -- do sth.
                print("finally can work")
            end
        },
    }
print("I can print normally!")
end

test()

调用test()后，运行结果如下：

又改了一版，格式输入看起来更容易理解，代码如下：

-- 异常捕获
function try1(block)
    local main = block.main
    local catch = block.catch
    local finally = block.finally

    assert(main)

    -- try to call it
    local ok, errors = xpcall(main, debug.traceback)
    if not ok then
        -- run the catch function
        if catch then
            catch(errors)
        end
    end

    -- run the finally function
    if finally then
        finally(ok, errors)
    end

    -- ok?
    if ok then
        return errors
    end
end

function test1()
try1{
        main = function ()
            xxx()
        end,
        catch = function (errors)
            print("catch : " .. errors)
        end,
        finally = function (ok, errors)
            print("finally : " .. tostring(ok))
        end,
    }
print("I can print normally!")
end

test1()

打印结果如下：