From b040fd21c39af992d48cc18334ffa9b08d4692a2 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Wed, 11 Sep 2024 15:27:10 -0600
Subject: [PATCH] Hide Message fields

---
 TODO.txt        |  1 -
 bytes/regexp.go |  6 +-----
 gigaparsec.go   | 53 +++++++++++++++++++++++++++++--------------------
 3 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/TODO.txt b/TODO.txt
index 4cd6371..d85353d 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,3 +1,2 @@
-Hide Message fields
 Test RuneReader
 Test Regexp
diff --git a/bytes/regexp.go b/bytes/regexp.go
index c371aa0..a4b9498 100644
--- a/bytes/regexp.go
+++ b/bytes/regexp.go
@@ -72,11 +72,7 @@ func Regexp(str string) gigaparsec.Parser[byte, string] {
 			if err != nil {
 				return gigaparsec.Result[byte, string]{}, fmt.Errorf("Regexp: unexpected error: %w", err)
 			}
-			return gigaparsec.Fail[byte, string](false, gigaparsec.Message{
-				Pos:      input.Pos(),
-				Got:      string(got),
-				Expected: []string{expected},
-			}), nil
+			return gigaparsec.Fail[byte, string](false, gigaparsec.MakeMessage(input.Pos(), string(got), expected)), nil
 		}
 		// Alas, this is a little wasteful because a Regexp can only return indices
 		// when searching a RuneReader.
diff --git a/gigaparsec.go b/gigaparsec.go
index 0538ce3..2f181e6 100644
--- a/gigaparsec.go
+++ b/gigaparsec.go
@@ -63,20 +63,40 @@ func (r Result[In, Out]) Consume(consumed bool) Result[In, Out] {
 	return r
 }
 
+func MakeMessage(pos uint64, got string, expected ...string) Message {
+	return Message{
+		pos:      pos,
+		got:      got,
+		expected: expected,
+	}
+}
+
 type Message struct {
-	Pos      uint64
-	Got      string
-	Expected []string
+	pos      uint64
+	got      string
+	expected []string
+}
+
+func (m Message) PosMethod() uint64 {
+	return m.pos
+}
+
+func (m Message) GotMethod() string {
+	return m.got
+}
+
+func (m Message) ExpectedMethod() []string {
+	return m.expected
 }
 
 func (m Message) expect(s string) Message {
-	m.Expected = []string{s}
+	m.expected = []string{s}
 	return m
 }
 
-func MessageOK(pos uint64) Message { return Message{Pos: pos} }
+func MessageOK(pos uint64) Message { return Message{pos: pos} }
 
-func MessageEnd(pos uint64) Message { return Message{Pos: pos, Got: "end of input"} }
+func MessageEnd(pos uint64) Message { return Message{pos: pos, got: "end of input"} }
 
 func MakeState[In any](c cursor.Cursor[In]) State[In] {
 	return State[In]{cursor: c}
@@ -127,10 +147,7 @@ func Satisfy[T any](pred func(T) bool) Parser[T, T] {
 		if pred(token[0]) {
 			return Succeed(true, token[0], next, MessageOK(state.Pos())), nil
 		}
-		return Fail[T, T](false, Message{
-			Pos: state.Pos(),
-			Got: fmt.Sprint(token),
-		}), nil
+		return Fail[T, T](false, MakeMessage(state.Pos(), fmt.Sprint(token))), nil
 	}
 }
 
@@ -146,11 +163,7 @@ func Slice[T comparable](s []T) Parser[T, []T] {
 			return Result[T, []T]{}, err
 		}
 		if !slices.Equal(s, token) {
-			return Fail[T, []T](false, Message{
-				Pos:      state.Pos(),
-				Got:      fmt.Sprint(token),
-				Expected: []string{expected},
-			}), nil
+			return Fail[T, []T](false, MakeMessage(state.Pos(), fmt.Sprint(token), expected)), nil
 		}
 		return Succeed(true, token, next, MessageOK(state.Pos())), nil
 	}
@@ -204,10 +217,10 @@ func Choose[In, Out any](p Parser[In, Out], ps ...Parser[In, Out]) Parser[In, Ou
 				qMsg = msg
 			}
 			if got == "" {
-				got = qMsg.Got
+				got = qMsg.got
 			}
 		}
-		msg := Message{Pos: input.Pos(), Got: got, Expected: slices.Concat(expecteds...)}
+		msg := MakeMessage(input.Pos(), got, slices.Concat(expecteds...)...)
 		if failed {
 			return Fail[In, Out](false, msg), nil
 		}
@@ -261,11 +274,7 @@ func end[In any](s State[In]) (Result[In, struct{}], error) {
 	if err != nil {
 		return Result[In, struct{}]{}, fmt.Errorf("End: unexpected error: %w", err)
 	}
-	return Fail[In, struct{}](false, Message{
-		Pos:      s.Pos(),
-		Got:      "",
-		Expected: []string{"end of input"},
-	}), nil
+	return Fail[In, struct{}](false, MakeMessage(s.Pos(), "", "end of input")), nil
 }
 
 func End[In any]() Parser[In, struct{}] {