Lua print table(類似PHP中的print_r/var_export)

標籤：lua   debug.dump   print_r   var_export   

會PHP的人都知道PHP中的print_r/var_export函數，可以方便的用於列印數組或匯出變數，Lua中沒有提供，實際應用中卻是很多時候需要類似的功能。

今天便封裝了個簡單函數，實作類別似功能，用來列印/匯出table：

-- dump.lua--[[dump對象@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)        str = string.gsub(str, "[%c\\\"]", {            ["\t"] = "\\t",            ["\r"] = "\\r",            ["\n"] = "\\n",            ["\""] = "\\\"",            ["\\"] = "\\\\",        })        return ‘"‘ .. 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

測試代碼：

-- test.lualocal obj = {    string1 = "Hi! My name is LiXianlin",    string2 = "aa\tbb\rcc\ndd\\ee\"ff",    string3 = "a\\tb\\rc\\n\\\\ee\"ff",    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)

輸出結果：

{        ["string1"] = "Hi! My name is LiXianlin",        [9.7] = 22222,        ["table"] = {                [1] = 1,                [2] = 2,                [3] = 3,                [4] = {                        ["b"] = 22,                        ["a"] = 21,                        ["c"] = 23,                },        },        ["float"] = 3.1415,        ["int"] = 9527,        ["string3"] = "a\\tb\\rc\\n\\\\ee\"ff",        ["bool"] = true,        ["string2"] = "aa\tbb\rcc\ndd\\ee\"ff",        [88] = 88888,}

函數特點：

1、理論上支援無限級table嵌套

2、格式化輸出，可讀性好

3、輸出結果可直接用於lua代碼

4、function、userdata、thread類型tostring輸出

5、當字串中含有控制字元時，可能有影響(代碼中僅對\t,\r,\n等進行了處理)

Lua print table(類似PHP中的print_r/var_export)