Regexp terminator escapes

Author: kddnewton

src/prism.c

@@ -9478,7 +9478,9 @@ parser_lex(pm_parser_t *parser) {
  case '\r':
  parser->current.end++;
  if (peek(parser) != '\n') {
- pm_token_buffer_push(&token_buffer, '\\');
+ if (lex_mode->as.regexp.terminator != '\r') {
+ pm_token_buffer_push(&token_buffer, '\\');
+ }
  pm_token_buffer_push(&token_buffer, '\r');
  break;
  }
@@ -9506,7 +9508,20 @@ parser_lex(pm_parser_t *parser) {
  escape_read(parser, &token_buffer.buffer, PM_ESCAPE_FLAG_REGEXP);
  break;
  default:
- if (lex_mode->as.regexp.terminator == '/' && peeked == '/') {
+ if (lex_mode->as.regexp.terminator == peeked) {
+ // Some characters when they are used as the
+ // terminator also receive an escape. They are
+ // enumerated here.
+ switch (peeked) {
+ case '$': case ')': case '*': case '+':
+ case '.': case '>': case '?': case ']':
+ case '^': case '|': case '}':
+ pm_token_buffer_push(&token_buffer, '\\');
+ break;
+ default:
+ break;
+ }
+
  pm_token_buffer_push(&token_buffer, peeked);
  parser->current.end++;
  break;