Added Repeat and listed necessary tests

TODO.txt

@@ -1,4 +1,4 @@
-Add repetition parsers to avoid some recursion
+Write Repeat tests
 Think about not requiring so much Pos() when making messages
 Rename Seq2 to Seq
 Document Seq

gigaparsec.go

@@ -342,3 +342,30 @@ func Pipe[In, Ignore, Through any](p Parser[In, Ignore]) func(Through) Parser[In
 		})
 	}
 }
+
+// Repeat applies p until p fails, and returns the collected outputs.
+// It succeeds if and only if p succeeds at least minCount times.
+// It consumes if and only if at least one of the applications of p consumes.
+func Repeat[In, Out any](minCount int, p Parser[In, Out]) Parser[In, []Out] {
+	return func(s State[In]) (Result[In, []Out], error) {
+		var values []Out
+		var consumed bool
+		next := s
+		for {
+			result, err := p(s)
+			if err != nil {
+				return Result[In, []Out]{}, fmt.Errorf("AtLeastN: %w", err)
+			}
+			consumed = consumed || result.Consumed()
+			if failed, _, msg := result.Failed(); failed {
+				if len(values) >= minCount {
+					return Succeed(consumed, values, next, MessageOK(s.Pos())), nil
+				}
+				return Fail[In, []Out](consumed, msg), nil
+			}
+			var value Out
+			_, _, value, next, _ = result.Succeeded()
+			values = append(values, value)
+		}
+	}
+}

parser_test.go

@@ -137,3 +137,10 @@ func TestLabel(t *testing.T) {
 func TestEnd(t *testing.T) {
 	Todo(t)
 }
+
+func TestRepeat(t *testing.T) {
+	t.Run("fails when number of successes is less than minCount", Todo)
+	t.Run("succeeds when number of successes is greater than minCount", Todo)
+	t.Run("consumes iff at least one application consumes", Todo)
+	t.Run("fails on error", Todo)
+}