ETS: Allow for matchspec-based replacement

2 files changed, 30 insertions, 1 deletions

diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 05401a2d40..36c803b40c 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -1491,6 +1491,27 @@ is_integer(X), is_integer(Y), X + Y < 4711]]></code>
     </func>
 
     <func>
+      <name name="select_replace" arity="2"/>
+      <fsummary>Match the objects in an ETS table against a match_spec and
+        replaces matching objects with the match_spec result</fsummary>
+      <desc>
+        <p>Matches the objects in the table <c><anno>Tab</anno></c> using a
+          <seealso marker="#match_spec">match_spec</seealso>. If the
+          an object is matched, and the match_spec result is an object with the
+          same key, the existing object is replaced with the match_spec result.
+          For any other result from the match_spec the object is kept
+          unchanged.</p>
+        <p>The function returns the number of objects actually
+          replaced in the table.</p>
+        <note>
+          <p>The <c>match_spec</c> has to return an object with the same key if
+            the object is to be replaced. No other return value will get the
+            object replaced.</p>
+        </note>
+      </desc>
+    </func>
+
+    <func>
       <name name="select_reverse" arity="1"/>
       <fsummary>Continue matching objects in an ETS table.</fsummary>
       <desc>
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index 90e19e6b9f..195a407570 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -70,7 +70,7 @@
          match_object/2, match_object/3, match_spec_compile/1,
          match_spec_run_r/3, member/2, new/2, next/2, prev/2,
          rename/2, safe_fixtable/2, select/1, select/2, select/3,
-         select_count/2, select_delete/2, select_reverse/1,
+         select_count/2, select_delete/2, select_replace/2, select_reverse/1,
          select_reverse/2, select_reverse/3, setopts/2, slot/2,
          take/2,
          update_counter/3, update_counter/4, update_element/3]).
@@ -379,6 +379,14 @@ select_count(_, _) ->
 select_delete(_, _) ->
     erlang:nif_error(undef).
 
+-spec select_replace(Tab, MatchSpec) -> NumReplaced when
+      Tab :: tab(),
+      MatchSpec :: match_spec(),
+      NumReplaced :: non_neg_integer().
+
+select_replace(_, _) ->
+    erlang:nif_error(undef).
+
 -spec select_reverse(Tab, MatchSpec) -> [Match] when
       Tab :: tab(),
       MatchSpec :: match_spec(),