proplists:normalize/2

对列表里元素进行一系列的替换/扩展操作

用法：

normalize(ListIn, Stages) -> ListOut

内部实现：

-spec normalize(ListIn, Stages) -> ListOut when
      ListIn :: [term()],
      Stages :: [Operation],
      Operation :: {'aliases', Aliases}
                 | {'negations', Negations}
                 | {'expand', Expansions},
      Aliases :: [{Key, Key}],
      Negations :: [{Key, Key}],
      Expansions :: [{Property :: property(), Expansion :: [term()]}],
      ListOut :: [term()].

normalize(L, [{aliases, As} | Xs]) ->
    normalize(substitute_aliases(As, L), Xs);
normalize(L, [{expand, Es} | Xs]) ->
    normalize(expand(Es, L), Xs);
normalize(L, [{negations, Ns} | Xs]) ->
    normalize(substitute_negations(Ns, L), Xs);
normalize(L, []) ->
    compact(L).

对列表里元素进行替换/扩展等一系列操作。对于一个 aliases 操作，函数 proplists:substitute_aliases/2 将调用给定的 aliases 列表；对于一个 negations 操作，函数 proplists:substitute_negations/2 将调用给定的 negation 列表；对于一个 expand 操作，函数 proplists:expand/2 将调用给定的 expansions 列表。最后的结果将自动被函数 proplists:compact/1 进行压缩操作。

proplists:normalize([a, b, c, d], [{aliases, [{a, apple}, {b, banana}]}]).

proplists:normalize([a, b, c, d], [{expand, [{d, [d, e, f, g]}]}]).

proplists:normalize([a, b, c, d], [{aliases, [{a, apple}, {b, banana}]}, {expand, [{d, [d, e, f, g]}]}]).

proplists:normalize([a, b, c, d], [{expand, [{d, [d, e, f, g]}]}, {aliases, [{a, apple}, {b, banana}]}]).