matcher_comment.go

package ulexer

// C的行注释
func CLineComment() Matcher {
	return (*cLineCommentMatcher)(nil)
}

func (*cLineCommentMatcher) TokenType() string {
	return "CLineComment"
}

type cLineCommentMatcher struct{}

func (self *cLineCommentMatcher) Read(lex *Lexer) (tk *Token) {

	if lex.Peek(0) != '/' || lex.Peek(1) != '/' {
		return nil
	}

	lex.Consume(2)

	var count int
	for {
		c := lex.Peek(count)

		if c == '\r' || c == '\n' {
			break
		}

		count++
	}

	if count == 0 {
		return nil
	}

	tk = lex.NewToken(count, self)

	lex.Consume(count)

	return
}

// Unix的行注释
func UnixLineComment() Matcher {
	return (*unixLineCommentMatcher)(nil)
}

func (*unixLineCommentMatcher) TokenType() string {
	return "UnixLineComment"
}

type unixLineCommentMatcher struct{}

func (self *unixLineCommentMatcher) Read(lex *Lexer) (tk *Token) {

	if lex.Peek(0) != '#' {
		return nil
	}

	lex.Consume(2)

	var count int
	for {
		c := lex.Peek(count)

		if c == '\r' || c == '\n' {
			break
		}

		count++
	}

	if count == 0 {
		return nil
	}

	tk = lex.NewToken(count, self)

	lex.Consume(count)

	return
}

// C块注释
func CBlockComment() Matcher {
	return (*cBlockCommentMatcher)(nil)
}

func (*cBlockCommentMatcher) TokenType() string {
	return "CBlockComment"
}

type cBlockCommentMatcher struct{}

func (self *cBlockCommentMatcher) Read(lex *Lexer) (tk *Token) {

	if lex.Peek(0) != '/' || lex.Peek(1) != '*' {
		return nil
	}

	lex.Consume(2)

	var (
		count  int
		endPos int
	)
	for {
		c := lex.Peek(count)

		switch c {
		case '*':
			endPos = count
		case '/':
			if endPos != 0 && count-endPos == 1 {
				count++
				goto EndOfParse
			}
		case 0: // EOF
			goto EndOfParse
		}
		count++
	}

EndOfParse:
	if count == 0 {
		return nil
	}

	// */ 不算到注释内容
	tk = lex.NewToken(count-2, self)

	lex.Consume(count)

	return
}