package wavefront import ( "bufio" "io" ) // Lexical Point Scanner type PointScanner struct { r *bufio.Reader } func NewScanner(r io.Reader) *PointScanner { return &PointScanner{r: bufio.NewReader(r)} } // read reads the next rune from the buffered reader. // Returns rune(0) if an error occurs (or io.EOF is returned). func (s *PointScanner) read() rune { ch, _, err := s.r.ReadRune() if err != nil { return eof } return ch } // unread places the previously read rune back on the reader. func (s *PointScanner) unread() { _ = s.r.UnreadRune() } // Scan returns the next token and literal value. func (s *PointScanner) Scan() (Token, string) { // Read the next rune ch := s.read() if isWhitespace(ch) { return WS, string(ch) } else if isLetter(ch) { return LETTER, string(ch) } else if isNumber(ch) { return NUMBER, string(ch) } // Otherwise read the individual character. switch ch { case eof: return EOF, "" case '\n': return NEWLINE, string(ch) case '.': return DOT, string(ch) case '-': return MINUS_SIGN, string(ch) case '_': return UNDERSCORE, string(ch) case '/': return SLASH, string(ch) case '\\': return BACKSLASH, string(ch) case ',': return COMMA, string(ch) case '"': return QUOTES, string(ch) case '=': return EQUALS, string(ch) } return ILLEGAL, string(ch) }