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-rw-r--r--lib/stdlib/doc/src/gb_sets.xml2
-rw-r--r--lib/stdlib/doc/src/ordsets.xml9
-rw-r--r--lib/stdlib/doc/src/sets.xml9
-rw-r--r--lib/stdlib/src/ordsets.erl9
-rw-r--r--lib/stdlib/src/sets.erl8
-rw-r--r--lib/stdlib/test/sets_SUITE.erl15
-rw-r--r--lib/stdlib/test/sets_test_lib.erl13
7 files changed, 51 insertions, 14 deletions
diff --git a/lib/stdlib/doc/src/gb_sets.xml b/lib/stdlib/doc/src/gb_sets.xml
index 7bfe477a11..2a3785dc27 100644
--- a/lib/stdlib/doc/src/gb_sets.xml
+++ b/lib/stdlib/doc/src/gb_sets.xml
@@ -83,6 +83,8 @@
</item>
<item><seealso marker="#is_element/2"><c>is_element/2</c></seealso>
</item>
+ <item><seealso marker="#is_empty/1"><c>is_empty/1</c></seealso>
+ </item>
<item><seealso marker="#is_set/1"><c>is_set/1</c></seealso>
</item>
<item><seealso marker="#is_subset/2"><c>is_subset/2</c></seealso>
diff --git a/lib/stdlib/doc/src/ordsets.xml b/lib/stdlib/doc/src/ordsets.xml
index 7b590932e4..2d891d7a5a 100644
--- a/lib/stdlib/doc/src/ordsets.xml
+++ b/lib/stdlib/doc/src/ordsets.xml
@@ -142,6 +142,15 @@
</func>
<func>
+ <name name="is_empty" arity="1"/>
+ <fsummary>Test for empty set.</fsummary>
+ <desc>
+ <p>Returns <c>true</c> if <c><anno>Ordset</anno></c> is an empty set,
+ otherwise <c>false</c>.</p>
+ </desc>
+ </func>
+
+ <func>
<name name="is_set" arity="1"/>
<fsummary>Test for an <c>Ordset</c>.</fsummary>
<desc>
diff --git a/lib/stdlib/doc/src/sets.xml b/lib/stdlib/doc/src/sets.xml
index 4934bed365..1ed96ddc3f 100644
--- a/lib/stdlib/doc/src/sets.xml
+++ b/lib/stdlib/doc/src/sets.xml
@@ -140,6 +140,15 @@
</func>
<func>
+ <name name="is_empty" arity="1"/>
+ <fsummary>Test for empty set.</fsummary>
+ <desc>
+ <p>Returns <c>true</c> if <c><anno>Set</anno></c> is an empty set,
+ otherwise <c>false</c>.</p>
+ </desc>
+ </func>
+
+ <func>
<name name="is_set" arity="1"/>
<fsummary>Test for a <c>Set</c>.</fsummary>
<desc>
diff --git a/lib/stdlib/src/ordsets.erl b/lib/stdlib/src/ordsets.erl
index 569407f5ef..939e147ad8 100644
--- a/lib/stdlib/src/ordsets.erl
+++ b/lib/stdlib/src/ordsets.erl
@@ -19,7 +19,7 @@
-module(ordsets).
--export([new/0,is_set/1,size/1,to_list/1,from_list/1]).
+-export([new/0,is_set/1,size/1,is_empty/1,to_list/1,from_list/1]).
-export([is_element/2,add_element/2,del_element/2]).
-export([union/2,union/1,intersection/2,intersection/1]).
-export([is_disjoint/2]).
@@ -60,6 +60,13 @@ is_set([], _) -> true.
size(S) -> length(S).
+%% is_empty(OrdSet) -> boolean().
+%% Return 'true' if OrdSet is an empty set, otherwise 'false'.
+-spec is_empty(Ordset) -> boolean() when
+ Ordset :: ordset(_).
+
+is_empty(S) -> S=:=[].
+
%% to_list(OrdSet) -> [Elem].
%% Return the elements in OrdSet as a list.
diff --git a/lib/stdlib/src/sets.erl b/lib/stdlib/src/sets.erl
index c65a13b22e..ac0fc80526 100644
--- a/lib/stdlib/src/sets.erl
+++ b/lib/stdlib/src/sets.erl
@@ -37,7 +37,7 @@
-module(sets).
%% Standard interface.
--export([new/0,is_set/1,size/1,to_list/1,from_list/1]).
+-export([new/0,is_set/1,size/1,is_empty/1,to_list/1,from_list/1]).
-export([is_element/2,add_element/2,del_element/2]).
-export([union/2,union/1,intersection/2,intersection/1]).
-export([is_disjoint/2]).
@@ -96,6 +96,12 @@ is_set(_) -> false.
Set :: set().
size(S) -> S#set.size.
+%% is_empty(Set) -> boolean().
+%% Return 'true' if Set is an empty set, otherwise 'false'.
+-spec is_empty(Set) -> boolean() when
+ Set :: set().
+is_empty(S) -> S#set.size=:=0.
+
%% to_list(Set) -> [Elem].
%% Return the elements in Set as a list.
-spec to_list(Set) -> List when
diff --git a/lib/stdlib/test/sets_SUITE.erl b/lib/stdlib/test/sets_SUITE.erl
index bec38000b2..7066d07e19 100644
--- a/lib/stdlib/test/sets_SUITE.erl
+++ b/lib/stdlib/test/sets_SUITE.erl
@@ -28,7 +28,7 @@
init_per_testcase/2,end_per_testcase/2,
create/1,add_element/1,del_element/1,
subtract/1,intersection/1,union/1,is_subset/1,
- is_set/1,fold/1,filter/1,
+ is_set/1,is_empty/1,fold/1,filter/1,
take_smallest/1,take_largest/1, iterate/1]).
-include_lib("common_test/include/ct.hrl").
@@ -48,7 +48,7 @@ suite() ->
all() ->
[create, add_element, del_element, subtract,
intersection, union, is_subset, is_set, fold, filter,
- take_smallest, take_largest, iterate].
+ take_smallest, take_largest, iterate, is_empty].
groups() ->
[].
@@ -345,6 +345,17 @@ is_set_1(M) ->
false = M(is_set, {}),
M(empty, []).
+is_empty(Config) when is_list(Config) ->
+ test_all(fun is_empty_1/1).
+
+is_empty_1(M) ->
+ S = M(from_list, [blurf]),
+ Empty = M(empty, []),
+
+ true = M(is_empty, Empty),
+ false = M(is_empty, S),
+ M(empty, []).
+
fold(Config) when is_list(Config) ->
test_all([{0,71},{125,129},{254,259},{510,513},{1023,1025},{9999,10001}],
fun fold_1/2).
diff --git a/lib/stdlib/test/sets_test_lib.erl b/lib/stdlib/test/sets_test_lib.erl
index 9f153822a2..93d027704b 100644
--- a/lib/stdlib/test/sets_test_lib.erl
+++ b/lib/stdlib/test/sets_test_lib.erl
@@ -32,7 +32,7 @@ new(Mod, Eq) ->
(from_list, L) -> Mod:from_list(L);
(intersection, {S1,S2}) -> intersection(Mod, Eq, S1, S2);
(intersection, Ss) -> intersection(Mod, Eq, Ss);
- (is_empty, S) -> is_empty(Mod, S);
+ (is_empty, S) -> Mod:is_empty(S);
(is_set, S) -> Mod:is_set(S);
(is_subset, {S,Set}) -> is_subset(Mod, Eq, S, Set);
(iterator, S) -> Mod:iterator(S);
@@ -56,7 +56,7 @@ singleton(Mod, E) ->
add_element(Mod, El, S0) ->
S = Mod:add_element(El, S0),
true = Mod:is_element(El, S),
- false = is_empty(Mod, S),
+ false = Mod:is_empty(S),
true = Mod:is_set(S),
S.
@@ -66,17 +66,10 @@ del_element(Mod, El, S0) ->
true = Mod:is_set(S),
S.
-is_empty(Mod, S) ->
- true = Mod:is_set(S),
- case erlang:function_exported(Mod, is_empty, 1) of
- true -> Mod:is_empty(S);
- false -> Mod:size(S) == 0
- end.
-
intersection(Mod, Equal, S1, S2) ->
S = Mod:intersection(S1, S2),
true = Equal(S, Mod:intersection(S2, S1)),
- Disjoint = is_empty(Mod, S),
+ Disjoint = Mod:is_empty(S),
Disjoint = Mod:is_disjoint(S1, S2),
Disjoint = Mod:is_disjoint(S2, S1),
S.