From b835581a732f3311e18aad10286d43f50a6006cf Mon Sep 17 00:00:00 2001
From: Adam Scarr <adam@vektah.net>
Date: Tue, 8 Aug 2017 19:24:49 +1000
Subject: complete string implementation

---
 parser.go | 93 +++++++++++++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 73 insertions(+), 20 deletions(-)

(limited to 'parser.go')

diff --git a/parser.go b/parser.go
index 62383b9..741df56 100644
--- a/parser.go
+++ b/parser.go
@@ -201,39 +201,92 @@ func charsImpl(matcher string, stopOn bool, repetition ...int) Parser {
 	}
 }
 
-func String(quote rune) Parser {
+func String(allowedQuotes string) Parser {
 	return NewParser("string", func(ps *State) Node {
 		ps.AutoWS()
-		var r rune
-		var w int
-		var matched int
-		r, matched = utf8.DecodeRuneInString(ps.Input[ps.Pos:])
-		if r != quote {
-			ps.ErrorHere("\"")
+
+		for i := 0; i < len(allowedQuotes); i++ {
+			if ps.Input[ps.Pos] == allowedQuotes[i] {
+
+			}
+		}
+		if !stringContainsByte(allowedQuotes, ps.Input[ps.Pos]) {
+			ps.ErrorHere(allowedQuotes)
 			return Node{}
 		}
+		quote := ps.Input[ps.Pos]
+
+		var end int = ps.Pos + 1
 
+		inputLen := len(ps.Input)
 		result := &bytes.Buffer{}
 
-		for ps.Pos+matched < len(ps.Input) {
-			r, w = utf8.DecodeRuneInString(ps.Input[ps.Pos+matched:])
-			matched += w
+		for end < inputLen {
+			switch ps.Input[end] {
+			case '\\':
+				if end+1 >= inputLen {
+					ps.ErrorHere(string(quote))
+					return Node{}
+				}
 
-			if r == '\\' {
-				r, w = utf8.DecodeRuneInString(ps.Input[ps.Pos+matched:])
-				result.WriteRune(r)
-				matched += w
-				continue
-			}
+				c := ps.Input[end+1]
+				if c == 'u' {
+					if end+6 >= inputLen {
+						ps.Error.Expected = "[a-f0-9]{4}"
+						ps.Error.pos = end + 2
+						return Node{}
+					}
 
-			if r == quote {
-				ps.Advance(matched)
+					r, ok := unhex(ps.Input[end+2 : end+6])
+					if !ok {
+						ps.Error.Expected = "[a-f0-9]"
+						ps.Error.pos = end + 2
+						return Node{}
+					}
+					result.WriteRune(r)
+					end += 6
+				} else {
+					result.WriteByte(c)
+					end += 2
+				}
+			case quote:
+				ps.Pos = end + 1
 				return Node{Token: result.String()}
+			default:
+				r, w := utf8.DecodeRuneInString(ps.Input[end:])
+				result.WriteRune(r)
+				end += w
 			}
-			result.WriteRune(r)
 		}
 
-		ps.ErrorHere("\"")
+		ps.ErrorHere(string(quote))
 		return Node{}
 	})
 }
+
+func stringContainsByte(s string, b byte) bool {
+	for i := 0; i < len(s); i++ {
+		if b == s[i] {
+			return true
+		}
+	}
+	return false
+}
+
+func unhex(b string) (v rune, ok bool) {
+	for _, c := range b {
+		v <<= 4
+		switch {
+		case '0' <= c && c <= '9':
+			v |= c - '0'
+		case 'a' <= c && c <= 'f':
+			v |= c - 'a' + 10
+		case 'A' <= c && c <= 'F':
+			v |= c - 'A' + 10
+		default:
+			return 0, false
+		}
+	}
+
+	return v, true
+}
-- 
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