code: def isAlphanum(c)
        return false if !c || c == EOF
        return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') ||
          (c >= 'A' && c <= 'Z') || c == '_' || c == '$' ||
            c == '\\' || Array(c[0].bytes).first > 126)
      end
docs: isAlphanum -- return true if the character is a letter, digit,
   underscore, # dollar sign, or non-ASCII character