LibJS: Optimize source_location_hint and add flag in print_errors

This optimizes the algorithm used in source_location_hint and adds a
flag to not print hints in print_errors.

Userland/Libraries/LibJS/Parser.h

@@ -107,15 +107,26 @@ class Parser {
  {
  if (!position.has_value())
  return {};
- // We need to modify the source to match what the lexer considers one line - normalizing
- // line terminators to \n is easier than splitting using all different LT characters.
- String source_string { source };
- source_string.replace("\r\n", "\n");
- source_string.replace("\r", "\n");
- source_string.replace(LINE_SEPARATOR, "\n");
- source_string.replace(PARAGRAPH_SEPARATOR, "\n");
+
  StringBuilder builder;
- builder.append(source_string.split_view('\n', true)[position.value().line - 1]);
+ String source_string { source };
+ GenericLexer lexer(source_string);
+ // Skip to the line we want
+ size_t current_line = 0;
+ while (current_line < position.value().line - 1) {
+ if (lexer.consume_specific("\n") || lexer.consume_specific("\r\n") || lexer.consume_specific(LINE_SEPARATOR) || lexer.consume_specific(PARAGRAPH_SEPARATOR))
+ current_line++;
+ else
+ lexer.ignore();
+ VERIFY(!lexer.is_eof());
+ }
+ // We are at the line, now add the chars to the string
+ while (!lexer.is_eof()) {
+ if (lexer.consume_specific("\n") || lexer.consume_specific("\r\n") || lexer.consume_specific(LINE_SEPARATOR) || lexer.consume_specific(PARAGRAPH_SEPARATOR))
+ break;
+ else
+ builder.append(lexer.consume());
+ }
  builder.append('\n');
  for (size_t i = 0; i < position.value().column - 1; ++i)
  builder.append(spacer);
@@ -126,12 +137,14 @@ class Parser {
 
  bool has_errors() const { return m_state.errors.size(); }
  const Vector<Error>& errors() const { return m_state.errors; }
- void print_errors() const
+ void print_errors(bool print_hint = true) const
  {
  for (auto& error : m_state.errors) {
- auto hint = error.source_location_hint(m_state.lexer.source());
- if (!hint.is_empty())
- warnln("{}", hint);
+ if (print_hint) {
+ auto hint = error.source_location_hint(m_state.lexer.source());
+ if (!hint.is_empty())
+ warnln("{}", hint);
+ }
  warnln("SyntaxError: {}", error.to_string());
  }
  }