pmod_basic.erl

%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2013. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%

-include_lib("pmod_transform/include/pmod.hrl").

-module(pmod_basic, [Props]).

-export([lookup/1,or_props/1,prepend/1,append/1,stupid_sum/0]).
-export([bar/1,bar_bar/1]).
-export([bc1/0, bc2/0]).
-export([collapse/1]).
-export([records/0]).

-import(lists, [keymap/3]).

lookup(Key) ->
    proplists:lookup(Key, Props).

or_props(Keys) ->
    Res = or_props_1(Keys, false),
    true = is_bool(Res),			%is_bool/1 does not use Props.
    Res.

prepend(Term) ->
    new([Term|Props]).

append(Term) ->
    pmod_basic:new(Props++[Term]).

or_props_1([K|Ks], Acc) ->
    or_props_1(Ks, proplists:get_bool(K, Props) or Acc);
or_props_1([], Acc) -> Acc.

is_bool(true) -> true;
is_bool(false) -> true;
is_bool(_) -> false.

stupid_sum() ->
    put(counter, 0),
    Res = stupid_sum_1(Props, 0),
    {Res,get(counter)}.

stupid_sum_1([H|T], Sum0) ->
    try add(Sum0, H) of
	Sum -> stupid_sum_1(T, Sum)
    catch
	error:_ -> stupid_sum_1(T, Sum0)
    after
	bump()
    end;
stupid_sum_1([], Sum) -> Sum.

bump() ->
    put(counter, get(counter)+1).

add(A, B) ->
    A+B.

-record(s, {a}).

bar(S) when S#s.a == 0 -> ok.

bar_bar(S) when is_record(S, s) -> ok;
bar_bar(_) -> error.


-record(r, {a,b,c}).

records() ->
    R = #r{a=42,b=19},
    update(R).

update(#r{a=A}=S) ->
    S#r{a=A+1,b=S#r.b+10}.

bc1() ->
    [A || <<A:1>> <= <<"9">> ].

bc2() ->
    << <<A:1>> || A <- [1,0,1,0] >>.

collapse(L) ->
    keymap(fun lists:sort/1, 2, L).