%%% -*- erlang-indent-level: 2 -*-
%%%-------------------------------------------------------------------
%%% Author: Kostis Sagonas
%%%
%%% Contains tests that manipulate and pattern match against tuples.
%%%-------------------------------------------------------------------
-module(basic_tuples).
-export([test/0]).
test() ->
Num = 4711,
ok = test_match({}, {1}, {1,2}, {1,2,3}, {1,2,3,4}, {1,2,3,4,5},
{1,2,3,4,5,6}, {1,2,3,4,5,6,7}, {1,2,3,4,5,6,7,8}),
ok = test_size({}, {a}, {{a},{b}}, {a,{b},c}),
ok = test_element({}, {a}, {a,b}, Num),
ok = test_setelement({}, {1}, {1,2}, 3, [1,2]),
ok = test_tuple_to_list({}, {a}, {a,b}, {a,b,c}, {a,b,c,d}, Num),
ok = test_list_to_tuple([], [a], [a,b], [a,b,c], [a,b,c,d], Num),
ok = test_tuple_with_case(),
ok = test_tuple_in_guard({a, b}, {a, b, c}),
ok.
%%--------------------------------------------------------------------
%% Tests matching of tuples
test_match(T0, T1, T2, T3, T4, T5, T6, T7, T8) ->
{} = T0,
{1} = T1,
{1, 2} = T2,
{1, 2, 3} = T3,
{1, 2, 3, 4} = T4,
{1, 2, 3, 4, 5} = T5,
{1, 2, 3, 4, 5, 6} = T6,
T6 = {1, 2, 3, 4, 5, 6},
T7 = {1, 2, 3, 4, 5, 6, 7},
{1, 2, 3, 4, 5, 6, 7, 8} = T8,
ok.
%%--------------------------------------------------------------------
%% Tests the size/1 and tuple_size/1 BIFs.
test_size(T0, T1, T2, T3) ->
[0, 1, 2, 3] = [size(T) || T <- [T0, T1, T2, T3]],
[0, 1, 2, 3] = [tuple_size(T) || T <- [T0, T1, T2, T3]],
ok.
%%--------------------------------------------------------------------
%% Tests element/2.
test_element(T0, T1, T2, N) ->
a = element(1, T1),
a = element(1, T2),
%% indirect calls to element/2
List = lists:seq(1, N),
Tuple = list_to_tuple(List),
ok = get_elements(List, Tuple, 1),
%% some cases that throw exceptions
{'EXIT', _} = (catch my_element(0, T2)),
{'EXIT', _} = (catch my_element(3, T2)),
{'EXIT', _} = (catch my_element(1, T0)),
{'EXIT', _} = (catch my_element(1, List)),
{'EXIT', _} = (catch my_element(1, N)),
{'EXIT', _} = (catch my_element(1.5, T2)),
ok.
my_element(Pos, Term) ->
element(Pos, Term).
get_elements([Element|Rest], Tuple, Pos) ->
Element = element(Pos, Tuple),
get_elements(Rest, Tuple, Pos + 1);
get_elements([], _Tuple, _Pos) ->
ok.
%%--------------------------------------------------------------------
%% Tests set_element/3.
test_setelement(T0, T1, Pair, Three, L) ->
{x} = setelement(1, T1, x),
{x, 2} = setelement(1, Pair, x),
{1, x} = setelement(2, Pair, x),
%% indirect calls to setelement/3
Tuple = list_to_tuple(lists:duplicate(2048, x)),
NewTuple = set_all_elements(Tuple, 1),
NewTuple = list_to_tuple(lists:seq(1+7, 2048+7)),
%% the following cases were rewritten to use the Three
%% variable in this weird way so as to silence the compiler
{'EXIT', _} = (catch setelement(Three - Three, Pair, x)),
{'EXIT', _} = (catch setelement(Three, Pair, x)),
{'EXIT', _} = (catch setelement(Three div Three, T0, x)),
{'EXIT', _} = (catch setelement(Three div Three, L, x)),
{'EXIT', _} = (catch setelement(Three / 2, Pair, x)),
ok.
set_all_elements(Tuple, Pos) when Pos =< tuple_size(Tuple) ->
set_all_elements(setelement(Pos, Tuple, Pos+7), Pos+1);
set_all_elements(Tuple, Pos) when Pos > tuple_size(Tuple) ->
Tuple.
%%--------------------------------------------------------------------
%% Tests tuple_to_list/1.
test_tuple_to_list(T0, T1, T2, T3, T4, Size) ->
[] = tuple_to_list(T0),
[a] = tuple_to_list(T1),
[a, b] = tuple_to_list(T2),
[a, b, c] = tuple_to_list(T3),
[a, b, c, d] = tuple_to_list(T4),
[a, b, c, d] = tuple_to_list(T4),
%% test a big tuple
List = lists:seq(1, Size),
Tuple = list_to_tuple(List),
Size = tuple_size(Tuple),
List = tuple_to_list(Tuple),
%% some cases that should result in errors
{'EXIT', _} = (catch my_tuple_to_list(element(2, T3))),
{'EXIT', _} = (catch my_tuple_to_list(Size)),
ok.
my_tuple_to_list(X) ->
tuple_to_list(X).
%%--------------------------------------------------------------------
%% Tests list_to_tuple/1.
test_list_to_tuple(L0, L1, L2, L3, L4, Size) ->
{} = list_to_tuple(L0),
{a} = list_to_tuple(L1),
{a, b} = list_to_tuple(L2),
{a, b, c} = list_to_tuple(L3),
{a, b, c, d} = list_to_tuple(L4),
{a, b, c, d, e} = list_to_tuple(L4++[e]),
%% test list_to_tuple with a big list
Tuple = list_to_tuple(lists:seq(1, Size)),
Size = tuple_size(Tuple),
%% some cases that should result in errors
{'EXIT', _} = (catch my_list_to_tuple({a,b})),
{'EXIT', _} = (catch my_list_to_tuple([hd(L1)|hd(L2)])),
ok.
my_list_to_tuple(X) ->
list_to_tuple(X).
%%--------------------------------------------------------------------
%% Tests that a case nested inside a tuple is ok.
%% (This was known to crash earlier versions of BEAM.)
test_tuple_with_case() ->
{reply, true} = tuple_with_case(),
ok.
tuple_with_case() ->
%% The following comments apply to the BEAM compiler.
void(), % Reset var count.
{reply, % Compiler will choose {x,1} for tuple.
case void() of % Call will reset var count.
{'EXIT', Reason} -> % Case will return in {x,1} (first free),
{error, Reason}; % but the tuple will be build in {x,1},
_ -> % so case value is lost and a circular
true % data element is built.
end}.
void() -> ok.
%%--------------------------------------------------------------------
%% Test to build a tuple in a guard.
test_tuple_in_guard(T2, T3) ->
%% T2 = {a, b}; T3 = {a, b, c}
ok = if T2 == {element(1, T3), element(2, T3)} -> ok;
true -> other
end,
ok = if T3 == {element(1, T3), element(2, T3), element(3, T3)} -> ok;
true -> other
end,
ok.
