Merge pull request #137 from yosefAlsuhaibani/escaped-dollar-sign-at-end-of-string-does-not-parse

Amend `scanner.c` to correctly parse strings of the form `"*\$"`

Author: fwcd

src/scanner.c

@@ -115,8 +115,20 @@ static bool scan_string_content(TSLexer *lexer, Stack *stack) {
       advance(lexer);
       // this dollar sign is escaped, so it must be content.
       // we consume it here so we don't enter the dollar sign case above,
-      // which leaves the possibility that it is an interpolation
-      if (lexer->lookahead == '$') advance(lexer);
+      // which leaves the possibility that it is an interpolation 
+      if (lexer->lookahead == '$') {
+        advance(lexer);
+        // however this leaves an edgecase where an escaped dollar sign could
+        // appear at the end of a string (e.g "aa\$") which isn't handled
+        // correctly; if we were at the end of the string, terminate properly
+        if (lexer->lookahead == end_char) {
+          stack_pop(stack);
+          advance(lexer);
+          lexer->mark_end(lexer);
+          lexer->result_symbol = STRING_END;
+          return true;
+        }
+      }
     } else if (lexer->lookahead == end_char) {
       if (is_triple) {
         lexer->mark_end(lexer);

test/corpus/literals.txt

@@ -114,6 +114,7 @@ More string interpolation
 "$1"
 "$ $ $"
 "\$foo"
+"\$"
 
 --------------------------------------------------------------------------------
 
@@ -130,7 +131,8 @@ More string interpolation
     (string_content)
     (string_content))
   (string_literal
-    (string_content)))
+    (string_content))
+  (string_literal))
 
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 Integer literals