From 0f854720ca2bad30246020bb01cdb903a5f9406d Mon Sep 17 00:00:00 2001
From: Adam Scarr <adam@vektah.net>
Date: Tue, 15 Aug 2017 18:57:00 +1000
Subject: [PATCH] Make until only work on string terminators

---
 combinator.go      | 30 ------------------------------
 combinator_test.go | 14 --------------
 parser.go          | 25 ++++++++++++++++++++++++-
 parser_test.go     | 16 ++++++++++++++++
 4 files changed, 40 insertions(+), 45 deletions(-)

diff --git a/combinator.go b/combinator.go
index 4e7e4a5..38145ee 100644
--- a/combinator.go
+++ b/combinator.go
@@ -145,36 +145,6 @@ func Maybe(parser Parserish) Parser {
 	})
 }
 
-// Until will consume all input until one of the given parsers match. This is running every parser over every byte,
-// so its probably going to be slow.
-func Until(parsers ...Parserish) Parser {
-	parserfied := ParsifyAll(parsers...)
-	return NewParser("Until()", func(ps *State, node *Result) {
-		ws := ps.WS
-		ps.WS = NoWhitespace
-		defer func() {
-			ps.WS = ws
-		}()
-		startPos := ps.Pos
-		for ps.Pos < len(ps.Input) {
-			endPos := ps.Pos
-			for _, p := range parserfied {
-				ps.Pos = endPos
-
-				p(ps, node)
-
-				if !ps.Errored() {
-					node.Token = ps.Input[startPos:endPos]
-					return
-				}
-				ps.Recover()
-			}
-			ps.Pos++
-		}
-		node.Token = ps.Input[startPos:ps.Pos]
-	})
-}
-
 // Bind will set the node .Result when the given parser matches
 // This is useful for giving a value to keywords and constant literals
 // like true and false. See the json parser for an example.
diff --git a/combinator_test.go b/combinator_test.go
index e792c47..c1eedb3 100644
--- a/combinator_test.go
+++ b/combinator_test.go
@@ -181,20 +181,6 @@ func TestMap(t *testing.T) {
 	})
 }
 
-func TestUntil(t *testing.T) {
-	parser := Until("world", ".")
-
-	t.Run("success", func(t *testing.T) {
-		result, _ := runParser("this is the end of the world", parser)
-		require.Equal(t, "this is the end of the ", result.Token)
-	})
-
-	t.Run("eof", func(t *testing.T) {
-		result, _ := runParser("this is the end of it all", parser)
-		require.Equal(t, "this is the end of it all", result.Token)
-	})
-}
-
 func TestBind(t *testing.T) {
 	parser := Bind("true", true)
 
diff --git a/parser.go b/parser.go
index fecf635..a612857 100644
--- a/parser.go
+++ b/parser.go
@@ -200,7 +200,7 @@ func Chars(matcher string, repetition ...int) Parser {
 }
 
 // NotChars accepts the full range of input from Chars, but it will stop when any
-// character matches.
+// character matches. If you need to match until you see a sequence use Until instead
 func NotChars(matcher string, repetition ...int) Parser {
 	return NewParser("!["+matcher+"]", charsImpl(matcher, true, repetition...))
 }
@@ -244,3 +244,26 @@ func charsImpl(matcher string, stopOn bool, repetition ...int) Parser {
 		ps.Advance(matched)
 	}
 }
+
+// Until will consume all input until one of the given terminator sequences is found. If you want to stop when seeing
+// single characters see NotChars instead
+func Until(terminators ...string) Parser {
+
+	return NewParser("Until", func(ps *State, node *Result) {
+		startPos := ps.Pos
+	loop:
+		for ps.Pos < len(ps.Input) {
+			for _, terminator := range terminators {
+				if ps.Pos+len(terminator) <= len(ps.Input) && ps.Input[ps.Pos:ps.Pos+len(terminator)] == terminator {
+					break loop
+				}
+			}
+			ps.Pos++
+		}
+
+		if ps.Pos == startPos {
+			ps.ErrorHere("something")
+		}
+		node.Token = ps.Input[startPos:ps.Pos]
+	})
+}
diff --git a/parser_test.go b/parser_test.go
index ce5f3e7..aaed25f 100644
--- a/parser_test.go
+++ b/parser_test.go
@@ -214,6 +214,22 @@ func TestAutoWS(t *testing.T) {
 	})
 }
 
+func TestUntil(t *testing.T) {
+	parser := Until("world", ".")
+
+	t.Run("success", func(t *testing.T) {
+		result, ps := runParser("this is the end of the world", parser)
+		require.Equal(t, "this is the end of the ", result.Token)
+		require.Equal(t, "world", ps.Get())
+	})
+
+	t.Run("eof", func(t *testing.T) {
+		result, ps := runParser("this is the end of it all", parser)
+		require.Equal(t, "this is the end of it all", result.Token)
+		require.Equal(t, "", ps.Get())
+	})
+}
+
 func runParser(input string, parser Parser) (Result, *State) {
 	ps := NewState(input)
 	result := Result{}