/src/mochilists.erl
Erlang | 122 lines | 67 code | 15 blank | 40 comment | 0 complexity | 1cb14eab14a7253272827c7d36f449ff MD5 | raw file
Possible License(s): MIT
- %% @copyright Copyright (c) 2010 Mochi Media, Inc.
- %% @author David Reid <dreid@mochimedia.com>
- %%
- %% Permission is hereby granted, free of charge, to any person obtaining a
- %% copy of this software and associated documentation files (the "Software"),
- %% to deal in the Software without restriction, including without limitation
- %% the rights to use, copy, modify, merge, publish, distribute, sublicense,
- %% and/or sell copies of the Software, and to permit persons to whom the
- %% Software is furnished to do so, subject to the following conditions:
- %%
- %% The above copyright notice and this permission notice shall be included in
- %% all copies or substantial portions of the Software.
- %%
- %% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- %% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- %% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- %% THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- %% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- %% FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
- %% DEALINGS IN THE SOFTWARE.
- %% @doc Utility functions for dealing with proplists.
- -module(mochilists).
- -author("David Reid <dreid@mochimedia.com>").
- -export([get_value/2, get_value/3, is_defined/2, set_default/2, set_defaults/2]).
- %% @spec set_default({Key::term(), Value::term()}, Proplist::list()) -> list()
- %%
- %% @doc Return new Proplist with {Key, Value} set if not is_defined(Key, Proplist).
- set_default({Key, Value}, Proplist) ->
- case is_defined(Key, Proplist) of
- true ->
- Proplist;
- false ->
- [{Key, Value} | Proplist]
- end.
- %% @spec set_defaults([{Key::term(), Value::term()}], Proplist::list()) -> list()
- %%
- %% @doc Return new Proplist with {Key, Value} set if not is_defined(Key, Proplist).
- set_defaults(DefaultProps, Proplist) ->
- lists:foldl(fun set_default/2, Proplist, DefaultProps).
- %% @spec is_defined(Key::term(), Proplist::list()) -> bool()
- %%
- %% @doc Returns true if Propist contains at least one entry associated
- %% with Key, otherwise false is returned.
- is_defined(Key, Proplist) ->
- lists:keyfind(Key, 1, Proplist) =/= false.
- %% @spec get_value(Key::term(), Proplist::list()) -> term() | undefined
- %%
- %% @doc Return the value of <code>Key</code> or undefined
- get_value(Key, Proplist) ->
- get_value(Key, Proplist, undefined).
- %% @spec get_value(Key::term(), Proplist::list(), Default::term()) -> term()
- %%
- %% @doc Return the value of <code>Key</code> or <code>Default</code>
- get_value(_Key, [], Default) ->
- Default;
- get_value(Key, Proplist, Default) ->
- case lists:keyfind(Key, 1, Proplist) of
- false ->
- Default;
- {Key, Value} ->
- Value
- end.
- %%
- %% Tests
- %%
- -ifdef(TEST).
- -include_lib("eunit/include/eunit.hrl").
- set_defaults_test() ->
- ?assertEqual(
- [{k, v}],
- set_defaults([{k, v}], [])),
- ?assertEqual(
- [{k, v}],
- set_defaults([{k, vee}], [{k, v}])),
- ?assertEqual(
- lists:sort([{kay, vee}, {k, v}]),
- lists:sort(set_defaults([{k, vee}, {kay, vee}], [{k, v}]))),
- ok.
- set_default_test() ->
- ?assertEqual(
- [{k, v}],
- set_default({k, v}, [])),
- ?assertEqual(
- [{k, v}],
- set_default({k, vee}, [{k, v}])),
- ok.
- get_value_test() ->
- ?assertEqual(
- undefined,
- get_value(foo, [])),
- ?assertEqual(
- undefined,
- get_value(foo, [{bar, baz}])),
- ?assertEqual(
- bar,
- get_value(foo, [{foo, bar}])),
- ?assertEqual(
- default,
- get_value(foo, [], default)),
- ?assertEqual(
- default,
- get_value(foo, [{bar, baz}], default)),
- ?assertEqual(
- bar,
- get_value(foo, [{foo, bar}], default)),
- ok.
- -endif.