From 8ca9f36739826313f1f81b46f14deb701df86705 Mon Sep 17 00:00:00 2001
From: Diego Augusto Molina <diegoaugustomolina@gmail.com>
Date: Wed, 27 Aug 2025 00:08:07 -0300
Subject: [PATCH 1/2] allow backticks to be quoted in string literals

---
 parser/lexer/lexer.go      | 42 +++++++++++++++++++++++++++++++++-----
 parser/lexer/lexer_test.go | 36 ++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/parser/lexer/lexer.go b/parser/lexer/lexer.go
index f417f02b..a8cf6a5b 100644
--- a/parser/lexer/lexer.go
+++ b/parser/lexer/lexer.go
@@ -242,15 +242,47 @@ func (l *Lexer) scanString(quote rune) (n int) {
 }
 
 func (l *Lexer) scanRawString(quote rune) (n int) {
-	ch := l.next() // read character after back tick
-	for ch != quote {
-		if ch == eof {
+	var escapedQuotes int
+loop:
+	for {
+		ch := l.next()
+		for ch == quote && l.peek() == quote {
+			// skip current and next char which are the quote escape sequence
+			l.next()
+			ch = l.next()
+			escapedQuotes++
+		}
+		switch ch {
+		case quote:
+			break loop
+		case eof:
 			l.error("literal not terminated")
 			return
 		}
-		ch = l.next()
 		n++
 	}
-	l.emitValue(String, l.source.String()[l.start.byte+1:l.end.byte-1])
+	str := l.source.String()[l.start.byte+1 : l.end.byte-1]
+
+	// handle simple case where no quoted backtick was found, then no allocation
+	// is needed for the new string
+	if escapedQuotes == 0 {
+		l.emitValue(String, str)
+		return
+	}
+
+	var b strings.Builder
+	var skipped bool
+	b.Grow(len(str) - escapedQuotes)
+	for _, r := range str {
+		if r == quote {
+			if !skipped {
+				skipped = true
+				continue
+			}
+			skipped = false
+		}
+		b.WriteRune(r)
+	}
+	l.emitValue(String, b.String())
 	return
 }
diff --git a/parser/lexer/lexer_test.go b/parser/lexer/lexer_test.go
index 5171f425..df3ea420 100644
--- a/parser/lexer/lexer_test.go
+++ b/parser/lexer/lexer_test.go
@@ -68,6 +68,22 @@ func TestLex(t *testing.T) {
 				{Kind: EOF},
 			},
 		},
+		{
+			"`escaped backticks` `` `a``b` ```` `a``` ```b` ```a````b``` ```````` ```a````` `````b```",
+			[]Token{
+				{Kind: String, Value: "escaped backticks"},
+				{Kind: String, Value: ""},
+				{Kind: String, Value: "a`b"},
+				{Kind: String, Value: "`"},
+				{Kind: String, Value: "a`"},
+				{Kind: String, Value: "`b"},
+				{Kind: String, Value: "`a``b`"},
+				{Kind: String, Value: "```"},
+				{Kind: String, Value: "`a``"},
+				{Kind: String, Value: "``b`"},
+				{Kind: EOF},
+			},
+		},
 		{
 			"a and orb().val #.",
 			[]Token{
@@ -332,6 +348,26 @@ literal not terminated (1:10)
  | id "hello
  | .........^
 
+id ` + "`" + `hello
+literal not terminated (1:10)
+ | id ` + "`" + `hello
+ | .........^
+
+id ` + "`" + `hello` + "``" + `
+literal not terminated (1:12)
+ | id ` + "`" + `hello` + "``" + `
+ | ...........^
+
+id ` + "`" + `` + "``" + `hello
+literal not terminated (1:12)
+ | id ` + "```" + `hello
+ | ...........^
+
+id ` + "`" + `hello` + "``" + ` world
+literal not terminated (1:18)
+ | id ` + "`" + `hello` + "``" + ` world
+ | .................^
+
 früh ♥︎
 unrecognized character: U+2665 '♥' (1:6)
  | früh ♥︎

From c5afe8f231a57d92b02993ca4b12e508c168a694 Mon Sep 17 00:00:00 2001
From: Diego Augusto Molina <diegoaugustomolina@gmail.com>
Date: Wed, 27 Aug 2025 10:35:52 -0300
Subject: [PATCH 2/2] remove redundant empty string

---
 parser/lexer/lexer_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/parser/lexer/lexer_test.go b/parser/lexer/lexer_test.go
index df3ea420..baa5aabb 100644
--- a/parser/lexer/lexer_test.go
+++ b/parser/lexer/lexer_test.go
@@ -358,7 +358,7 @@ literal not terminated (1:12)
  | id ` + "`" + `hello` + "``" + `
  | ...........^
 
-id ` + "`" + `` + "``" + `hello
+id ` + "```" + `hello
 literal not terminated (1:12)
  | id ` + "```" + `hello
  | ...........^