Prism::Translation::Parser::Lexer#unescape_string

# File tmp/rubies/ruby-4.0.0/lib/prism/translation/parser/lexer.rb, line 675
def unescape_string(string, quote)
  # In single-quoted heredocs, everything is taken literally.
  return string if quote == "<<'"

  # OPTIMIZATION: Assume that few strings need escaping to speed up the common case.
  return string unless string.include?("\\")

  # Enclosing character for the string. `"` for `"foo"`, `{` for `%w{foo}`, etc.
  delimiter = quote[-1]

  if regexp?(quote)
    # Should be escaped handled to single-quoted heredocs. The only character that is
    # allowed to be escaped is the delimiter, except when that also has special meaning
    # in the regexp. Since all the symetry delimiters have special meaning, they don't need
    # to be considered separately.
    if REGEXP_META_CHARACTERS.include?(delimiter)
      string
    else
      # There can never be an even amount of backslashes. It would be a syntax error.
      string.gsub(/\\(#{Regexp.escape(delimiter)})/, '\1')
    end
  elsif interpolation?(quote)
    # Appending individual escape sequences may force the string out of its intended
    # encoding. Start out with binary and force it back later.
    result = "".b

    scanner = StringScanner.new(string)
    while (skipped = scanner.skip_until(/\\/))
      # Append what was just skipped over, excluding the found backslash.
      result.append_as_bytes(string.byteslice(scanner.pos - skipped, skipped - 1))
      escape_read(result, scanner, false, false)
    end

    # Add remaining chars
    result.append_as_bytes(string.byteslice(scanner.pos..))
    result.force_encoding(source_buffer.source.encoding)
  else
    delimiters = Regexp.escape("#{delimiter}#{DELIMITER_SYMETRY[delimiter]}")
    string.gsub(/\\([\\#{delimiters}])/, '\1')
  end
end