Stamp/Ignore now Stamp/Discard/Ignore

1 files changed, 40 insertions, 0 deletions

diff --git a/src/packrat-parsers.adb b/src/packrat-parsers.adb
index e4fa97d..0ddd864 100644
--- a/src/packrat-parsers.adb
+++ b/src/packrat-parsers.adb
@@ -622,6 +622,46 @@ package body Packrat.Parsers is
     end Stamp;
 
 
+    function Discard
+           (Input   : in     Traits.Element_Array;
+            Context : in out Parser_Context;
+            Start   : in     Positive)
+        return Combinator_Result
+    is
+        function Actual
+               (Context : in out Parser_Context)
+            return Combinator_Result
+        is
+            Salt : Combinator_Result := Combo (Input, Context, Start);
+            Processed : Result_Sets.Set;
+        begin
+            if Salt.Status = Failure then
+                declare
+                    Error : String := Packrat.Errors.Encode
+                        (Traits.Label_Enum'Image (Label), Start);
+                begin
+                    if Ada.Strings.Unbounded.Index (Context.Error_String, Error) = 0 then
+                        Ada.Strings.Unbounded.Append (Context.Error_String, Error);
+                    end if;
+                end;
+                return Salt;
+            end if;
+            for R of Salt.Results loop
+                Processed.Include
+                   ((Finish => R.Finish,
+                     Value  => Elem_Holds.Empty_Holder,
+                     Tokens => Tok_Holds.Empty_Holder));
+            end loop;
+            Salt.Results := Processed;
+            return Salt;
+        end Actual;
+        function Memo is new Memoize (To_Key (Start, Discard'Access), Actual);
+        function Curt is new Curtailment (To_Key (Start, Discard'Access), Input, Memo);
+    begin
+        return Curt (Context);
+    end Discard;
+
+
     function Ignore
            (Input   : in     Traits.Element_Array;
             Context : in out Parser_Context;