Example #1
0
// Assumes '"' has already been encountered.
func lexLiteral(l *lex.Lexer) lex.StateFn {
	for {
		r := l.Next()
		if r == '\u005c' { // backslash
			r = l.Next()
			continue // This would skip over the escaped rune.
		}

		if r == lex.EOF || isEndLiteral(r) {
			break
		}
	}
	l.Backup()

	l.Emit(itemLiteral)
	l.Next()   // Move to end literal.
	l.Ignore() // Ignore end literal.
	l.Depth++

	r := l.Peek()
	if r == '@' {
		return lexLanguage(l)
	}

	if r == '^' {
		return lexObjectType(l)
	}

	return lexText
}
Example #2
0
// Assumes that the current rune is '_'.
func lexBlankNode(l *lex.Lexer, styp lex.ItemType,
	sfn lex.StateFn) lex.StateFn {

	// RDF Blank Node.
	// TODO: At some point do checkings based on the guidelines. For now,
	// just accept everything until space.
	l.AcceptUntil(isSpace)
	r := l.Peek()
	if r == lex.EOF {
		return l.Errorf("Unexpected end of subject")
	}

	if isSpace(r) {
		l.Emit(styp)
		return sfn
	}

	return l.Errorf("Invalid character %v found for itemType: %v", r, styp)
}
Example #3
0
func lexUidNode(l *lex.Lexer, styp lex.ItemType, sfn lex.StateFn) lex.StateFn {
	l.AcceptUntil(isSpace)
	r := l.Peek()
	if r == lex.EOF {
		return l.Errorf("Unexpected end of uid subject")
	}

	in := l.Input[l.Start:l.Pos]
	if !strings.HasPrefix(in, "_uid_:") {
		return l.Errorf("Expected _uid_: Found: %v", l.Input[l.Start:l.Pos])
	}

	if _, err := strconv.ParseUint(in[6:], 0, 64); err != nil {
		return l.Errorf("Unable to convert '%v' to UID", in[6:])
	}

	if isSpace(r) {
		l.Emit(styp)
		return sfn
	}

	return l.Errorf("Invalid character %v found for UID node itemType: %v", r,
		styp)
}