erlang下好用的json库ej

    erlang 下边的json 库用过几个，今天发现了ej库，解析和生成都很方便，下边是使用说明,里边详细的用法看里边的例子就可以了，这里给出的是为什么这么用，里边数据是怎么生成的。

1. ej  库下载地址是：

https://codeload.github.com/seth/ej/zip/master

2. 使用说明

% menu.json file

%{"menu": {
%"id": "file",
%"value": "File",
%"popup": {
%"menuitem": [
%{"value": "New", "onclick": "CreateNewDoc()"},
%{"value": "Open", "onclick": "OpenDoc()"},
%{"value": "Close", "onclick": "CloseDoc()"}
%]
%}
%}}

% menu.terms

%{struct,
%[{<<"menu">>,
%{struct,
%[{<<"id">>,<<"file">>},
%{<<"value">>,<<"File">>},
%{<<"popup">>,
%{struct,
%[{<<"menuitem">>,
%[{struct,
%[{<<"value">>,<<"New">>},
%{<<"onclick">>,<<"CreateNewDoc()">>}]},
%{struct,
%[{<<"value">>,<<"Open">>},
%{<<"onclick">>,<<"OpenDoc()">>}]},
%{struct,
%[{<<"value">>,<<"Close">>},
%{<<"onclick">>,<<"CloseDoc()">>}]}]}]}}]}}]}.

% menu.alt_terms
%{[{<<"menu">>,
%{[{<<"id">>,<<"file">>},
%{<<"value">>,<<"File">>},
%{<<"popup">>,
%{[{<<"menuitem">>,
%[{[{<<"value">>,<<"New">>},{<<"onclick">>,<<"CreateNewDoc()">>}]},
%{[{<<"value">>,<<"Open">>},{<<"onclick">>,<<"OpenDoc()">>}]},
%{[{<<"value">>,<<"Close">>},
%{<<"onclick">>,<<"CloseDoc()">>}]}]}]}}]}}]}.

% 产生测试数据
make_terms(JsonFile) ->
    {ok, Json} = file:read_file(JsonFile),
    Base = filename:basename(JsonFile),
    Decoder = mochijson2:decoder([{object_hook, fun({struct,L}) -> {L} end}]),
    AltTerms = Decoder(Json),
    Terms = mochijson2:decode(Json),
    file:write_file(Base ++ ".terms", io_lib:format("~p.~n", [Terms])),
    file:write_file(Base ++ ".alt_terms", io_lib:format("~p.~n", [AltTerms])).

getwid()->
    {[{<<"widget">>,
        {[{<<"version">>,<<"1">>},
            {<<"values">>,[1,2,3,4,5]},
            {<<"debug">>,<<"on">>},
            {<<"window">>,
                {[{<<"title">>,<<"Sample Konfabulator Widget">>},
                    {<<"name">>,<<"main_window">>},
                    {<<"width">>,500},
                    {<<"height">>,500}]}},
            {<<"image">>,
                {[{<<"src">>,<<"Images/Sun.png">>},
                    {<<"name">>,<<"sun1">>},
                    {<<"hOffset">>,250},
                    {<<"vOffset">>,250},
                    {<<"alignment">>,<<"center">>}]}},
            {<<"text">>,
                {[{<<"data">>,<<"Click Here">>},
                    {<<"size">>,36},
                    {<<"style">>,<<"bold">>},
                    {<<"name">>,<<"text1">>},
                    {<<"hOffset">>,250},
                    {<<"vOffset">>,100},
                    {<<"alignment">>,<<"center">>},
                    {<<"onMouseUp">>,
                        <<"sun1.opacity = (sun1.opacity / 100) * 90;">>}]}}]}}]}.

getmenu()->
    {[{<<"menu">>,
        {[{<<"id">>,<<"file">>},
            {<<"value">>,<<"File">>},
            {<<"popup">>,
                {[{<<"menuitem">>,
                    [{[{<<"value">>,<<"New">>},{<<"onclick">>,<<"CreateNewDoc()">>}]},
                        {[{<<"value">>,<<"Open">>},{<<"onclick">>,<<"OpenDoc()">>}]},
                        {[{<<"value">>,<<"Close">>},
                            {<<"onclick">>,<<"CloseDoc()">>}]}]}]}}]}}]}.

test()->
    Wid = getwid(),

    {ok, [Widget]} = file:consult("/home/yangzm/tmp/widget.alt_terms"),
    Ret = ej:get({"widget", "version"}, Wid),