code: func (r *Lexer) Delim(c byte) {
  	if r.token.kind == tokenUndef && r.Ok() {
  		r.FetchToken()
  	}
  
  	if !r.Ok() || r.token.delimValue != c {
  		r.consume() // errInvalidToken can change token if UseMultipleErrors is enabled.
  		r.errInvalidToken(string([]byte{c}))
  	} else {
  		r.consume()
  	}
  }
docs: // Delim consumes a token and verifies that it is the given delimiter.