Lua ダンプ テーブル (PHP の print_r/var_export に似ています)

Lua dump table(类似PHP中的print_r/var_export)

会PHP的人都知道PHP中的print_r/var_export函数，可以方便的用于打印数组或导出变量，Lua中没有提供，实际应用中却是很多时候需要类似的功能。

今天便封装了个简单函数，实现类似功能，用来打印/导出table：

-- dump.lua--[[dump对象@param mixed obj@return string]]function debug.dump(obj)    local getIndent, quoteStr, wrapKey, wrapVal, dumpObj    getIndent = function(level)        return string.rep("\t", level)    end    quoteStr = function(str)        return '"' .. string.gsub(str, '"', '\\"') .. '"'    end    wrapKey = function(val)        if type(val) == "number" then            return "[" .. val .. "]"        elseif type(val) == "string" then            return "[" .. quoteStr(val) .. "]"        else            return "[" .. tostring(val) .. "]"        end    end    wrapVal = function(val, level)        if type(val) == "table" then            return dumpObj(val, level)        elseif type(val) == "number" then            return val        elseif type(val) == "string" then            return quoteStr(val)        else            return tostring(val)        end    end    dumpObj = function(obj, level)        if type(obj) ~= "table" then            return wrapVal(obj)        end        level = level + 1        local tokens = {}        tokens[#tokens + 1] = "{"        for k, v in pairs(obj) do            tokens[#tokens + 1] = getIndent(level) .. wrapKey(k) .. " = " .. wrapVal(v, level) .. ","        end        tokens[#tokens + 1] = getIndent(level - 1) .. "}"        return table.concat(tokens, "\n")    end    return dumpObj(obj, 0)end

测试代码：

-- test.lualocal obj = {    string = "hello",    int = 9527,    float = 3.1415,    bool = true,    table = {        1, 2, 3,        {            a = 21,            b = 22,            c = 23,        },    },    [88] = 88888,    [9.7] = 22222,}print(debug.dump(obj))

输出结果：

{        ["float"] = 3.1415,        [9.7] = 22222,        ["string"] = "hello",        [88] = 88888,        ["bool"] = true,        ["int"] = 9527,        ["table"] = {                [1] = 1,                [2] = 2,                [3] = 3,                [4] = {                        ["b"] = 22,                        ["a"] = 21,                        ["c"] = 23,                },        },}

函数特点：

1、理论上支持无限级table嵌套

2、格式化输出，可读性好

3、输出结果可直接用于lua代码

4、function、userdata、thread类型tostring输出