我的Erlang编程技巧大全

这里集中记录我的Erlang编程过程中零散发现的小的技巧以及代码之类的
防止被不良网站抓取，先不写具体内容，过几天再来补上

防止被不良网站抓取，先不写具体内容，过几天再来补上

#### 方便debug的macro定义 #### 2010-11-06
#### 一个函数加载所有的重新编译的代码 #### 2010-10-23
经常，会改变一个代码，逐个l(module)的话，很麻烦，一个lm()全搞定

lm() ->
  [c:l(M) || M <- mm()].

mm() ->
  modified_modules().

modified_modules() ->
  [M || {M, _} <- code:all_loaded(), 
        module_modified(M) == true].

module_modified(Module) ->
  case code:is_loaded(Module) of
    {file, preloaded} ->
      false;
    {file, Path} ->
      CompileOpts = 
        proplists:get_value(compile, Module:module_info()),
      CompileTime = proplists:get_value(time, CompileOpts),
      Src = proplists:get_value(source, CompileOpts),
      module_modified(Path, CompileTime, Src);
    _ ->
      false
end.

module_modified(Path, PrevCompileTime, PrevSrc) ->
  case find_module_file(Path) of
    false ->
      false;
    ModPath ->
      case beam_lib:chunks(ModPath, ["CInf"]) of
        {ok, {_, [{_, CB}]}} ->
          CompileOpts =  binary_to_term(CB),
          CompileTime = proplists:get_value(time,                             
                                            CompileOpts),
          Src = proplists:get_value(source, CompileOpts),
          not (CompileTime == PrevCompileTime) and 
              (Src == PrevSrc);
        _ ->
          false
      end
end.

find_module_file(Path) ->
  case file:read_file_info(Path) of
    {ok, _} ->
      Path;
    _ ->
      %% may be the path was changed
      case code:where_is_file(filename:basename(Path)) of
        non_existing ->
          false;
        NewPath ->
          NewPath
      end
  end.

#### 方便debug的macro定义 #### 2010-11-06

-define(x(X), io:format("~p~p: ~s = ~p~n", [?MODULE, ?LINE, ??X, X])).

test() ->
    VeryLongVariableName = foo(),
    ?x(VeryLongVariableName).