diff options
| -rw-r--r-- | lib/stdlib/doc/src/dict.xml | 7 | ||||
| -rw-r--r-- | lib/stdlib/doc/src/orddict.xml | 7 | ||||
| -rw-r--r-- | lib/stdlib/src/dict.erl | 7 | ||||
| -rw-r--r-- | lib/stdlib/src/orddict.erl | 8 | ||||
| -rw-r--r-- | lib/stdlib/test/dict_SUITE.erl | 11 | ||||
| -rw-r--r-- | lib/stdlib/test/dict_test_lib.erl | 1 |
6 files changed, 38 insertions, 3 deletions
diff --git a/lib/stdlib/doc/src/dict.xml b/lib/stdlib/doc/src/dict.xml index b8cf61af80..6ff81b56ee 100644 --- a/lib/stdlib/doc/src/dict.xml +++ b/lib/stdlib/doc/src/dict.xml @@ -177,6 +177,13 @@ merge(Fun, D1, D2) -> </desc> </func> <func> + <name name="is_empty" arity="1"/> + <fsummary>Return true if the dictionary is empty</fsummary> + <desc> + <p>Returns <c>true</c> if <c><anno>Dict</anno></c> has no elements, <c>false</c> otherwise.</p> + </desc> + </func> + <func> <name name="store" arity="3"/> <fsummary>Store a value in a dictionary</fsummary> <desc> diff --git a/lib/stdlib/doc/src/orddict.xml b/lib/stdlib/doc/src/orddict.xml index b6aee7a7d6..6d1702bc59 100644 --- a/lib/stdlib/doc/src/orddict.xml +++ b/lib/stdlib/doc/src/orddict.xml @@ -187,6 +187,13 @@ merge(Fun, D1, D2) -> </desc> </func> <func> + <name name="is_empty" arity="1"/> + <fsummary>Return true if the dictionary is empty</fsummary> + <desc> + <p>Returns <c>true</c> if <c><anno>Orddict</anno></c> has no elements, <c>false</c> otherwise.</p> + </desc> + </func> + <func> <name name="store" arity="3"/> <fsummary>Store a value in a dictionary</fsummary> <desc> diff --git a/lib/stdlib/src/dict.erl b/lib/stdlib/src/dict.erl index e3bfb6c2e2..e67433ffb7 100644 --- a/lib/stdlib/src/dict.erl +++ b/lib/stdlib/src/dict.erl @@ -36,7 +36,7 @@ -module(dict). %% Standard interface. --export([new/0,is_key/2,to_list/1,from_list/1,size/1]). +-export([new/0,is_key/2,to_list/1,from_list/1,size/1,is_empty/1]). -export([fetch/2,find/2,fetch_keys/1,erase/2]). -export([store/3,append/3,append_list/3,update/3,update/4,update_counter/3]). -export([fold/3,map/2,filter/2,merge/3]). @@ -112,6 +112,11 @@ from_list(L) -> size(#dict{size=N}) when is_integer(N), N >= 0 -> N. +-spec is_empty(Dict) -> boolean() when + Dict :: dict(). + +is_empty(#dict{size=N}) -> N =:= 0. + -spec fetch(Key, Dict) -> Value when Key :: term(), Dict :: dict(), diff --git a/lib/stdlib/src/orddict.erl b/lib/stdlib/src/orddict.erl index 45d3c84b3e..da60fc1bb6 100644 --- a/lib/stdlib/src/orddict.erl +++ b/lib/stdlib/src/orddict.erl @@ -20,7 +20,7 @@ -module(orddict). %% Standard interface. --export([new/0,is_key/2,to_list/1,from_list/1,size/1]). +-export([new/0,is_key/2,to_list/1,from_list/1,size/1,is_empty/1]). -export([fetch/2,find/2,fetch_keys/1,erase/2]). -export([store/3,append/3,append_list/3,update/3,update/4,update_counter/3]). -export([fold/3,map/2,filter/2,merge/3]). @@ -64,6 +64,12 @@ from_list(Pairs) -> size(D) -> length(D). +-spec is_empty(Orddict) -> boolean() when + Orddict :: orddict(). + +is_empty([]) -> true; +is_empty([_|_]) -> false. + -spec fetch(Key, Orddict) -> Value when Key :: term(), Value :: term(), diff --git a/lib/stdlib/test/dict_SUITE.erl b/lib/stdlib/test/dict_SUITE.erl index 0223240479..69814e12ce 100644 --- a/lib/stdlib/test/dict_SUITE.erl +++ b/lib/stdlib/test/dict_SUITE.erl @@ -17,7 +17,7 @@ %% %CopyrightEnd% %% -%% This module tests the ordsets, sets, and gb_sets modules. +%% This module tests the orddict, dict, and gb_trees modules. %% -module(dict_SUITE). @@ -68,6 +68,7 @@ create_1(M) -> D0 = M(empty, []), [] = M(to_list, D0), 0 = M(size, D0), + true = M(is_empty, D0), D0. store(Config) when is_list(Config) -> @@ -81,6 +82,14 @@ store_1(List, M) -> D1 = foldl(fun({K,V}, Dict) -> M(enter, {K,V,Dict}) end, M(empty, []), List), true = M(equal, {D0,D1}), + case List of + [] -> + true = M(is_empty, D0), + true = M(is_empty, D1); + [_|_] -> + false = M(is_empty, D0), + false = M(is_empty, D1) + end, D0. %%% diff --git a/lib/stdlib/test/dict_test_lib.erl b/lib/stdlib/test/dict_test_lib.erl index e308fd0721..4fdb4fa0bd 100644 --- a/lib/stdlib/test/dict_test_lib.erl +++ b/lib/stdlib/test/dict_test_lib.erl @@ -28,6 +28,7 @@ new(Mod, Eq) -> (from_list, L) -> from_list(Mod, L); (module, []) -> Mod; (size, D) -> Mod:size(D); + (is_empty, D) -> Mod:is_empty(D); (to_list, D) -> to_list(Mod, D) end. |