package lexer import "strconv" import "git.tebibyte.media/arf/arf/infoerr" // tokenizeString tokenizes a string or rune literal. func (lexer *lexingOperation) tokenizeString () (err error) { token := lexer.newToken() err = lexer.nextRune() if err != nil { return } got := "" tokenWidth := 2 for { if lexer.char == '\\' { err = lexer.nextRune() tokenWidth ++ if err != nil { return } var actual rune var amountRead int actual, amountRead, err = lexer.getEscapeSequence() tokenWidth += amountRead if err != nil { return } got += string(actual) } else { got += string(lexer.char) err = lexer.nextRune() tokenWidth ++ if err != nil { return } } if lexer.char == '\'' { break } } err = lexer.nextRune() if err != nil { return } token.kind = TokenKindString token.value = got token.location.SetWidth(tokenWidth) lexer.addToken(token) return } // escapeSequenceMap contains basic escape sequences and how they map to actual // runes. var escapeSequenceMap = map[rune] rune { 'a': '\x07', 'b': '\x08', 'f': '\x0c', 'n': '\x0a', 'r': '\x0d', 't': '\x09', 'v': '\x0b', '\'': '\'', '\\': '\\', } // getEscapeSequence reads an escape sequence in a string or rune literal. func (lexer *lexingOperation) getEscapeSequence () ( result rune, amountRead int, err error, ) { result, exists := escapeSequenceMap[lexer.char] if exists { err = lexer.nextRune() amountRead ++ return } else if lexer.char >= '0' && lexer.char <= '7' { // octal escape sequence number := string(lexer.char) err = lexer.nextRune() amountRead ++ if err != nil { return } for len(number) < 3 { if lexer.char < '0' || lexer.char > '7' { break } number += string(lexer.char) err = lexer.nextRune() amountRead ++ if err != nil { return } } if len(number) < 3 { err = infoerr.NewError ( lexer.file.Location(1), "octal escape sequence too short", infoerr.ErrorKindError) return } parsedNumber, _ := strconv.ParseInt(number, 8, 8) result = rune(parsedNumber) } else if lexer.char == 'x' || lexer.char == 'u' || lexer.char == 'U' { // hexidecimal escape sequence want := 2 if lexer.char == 'u' { want = 4 } if lexer.char == 'U' { want = 8 } number := "" err = lexer.nextRune() amountRead ++ if err != nil { return } for len(number) < want { notLower := lexer.char < 'a' || lexer.char > 'f' notUpper := lexer.char < 'A' || lexer.char > 'F' notNum := lexer.char < '0' || lexer.char > '9' if notLower && notUpper && notNum { break } number += string(lexer.char) err = lexer.nextRune() amountRead ++ if err != nil { return } } if len(number) < want { err = infoerr.NewError ( lexer.file.Location(1), "hex escape sequence too short ", infoerr.ErrorKindError) return } parsedNumber, _ := strconv.ParseInt(number, 16, want * 4) result = rune(parsedNumber) } else { err = infoerr.NewError ( lexer.file.Location(1), "unknown escape character " + string(lexer.char), infoerr.ErrorKindError) return } return }