func()

in syntax/scan.go [827:908]

• 68 lines of code
• 19 McCabe index (conditional complexity)

func (sc *scanner) scanString(val *tokenValue, quote rune) Token {
	start := sc.pos
	triple := len(sc.rest) >= 3 && sc.rest[0] == byte(quote) && sc.rest[1] == byte(quote) && sc.rest[2] == byte(quote)
	sc.readRune()

	// String literals may contain escaped or unescaped newlines,
	// causing them to span multiple lines (gulps) of REPL input;
	// they are the only such token. Thus we cannot call endToken,
	// as it assumes sc.rest is unchanged since startToken.
	// Instead, buffer the token here.
	// TODO(adonovan): opt: buffer only if we encounter a newline.
	raw := new(strings.Builder)

	// Copy the prefix, e.g. r' or " (see startToken).
	raw.Write(sc.token[:len(sc.token)-len(sc.rest)])

	if !triple {
		// single-quoted string literal
		for {
			if sc.eof() {
				sc.error(val.pos, "unexpected EOF in string")
			}
			c := sc.readRune()
			raw.WriteRune(c)
			if c == quote {
				break
			}
			if c == '\n' {
				sc.error(val.pos, "unexpected newline in string")
			}
			if c == '\\' {
				if sc.eof() {
					sc.error(val.pos, "unexpected EOF in string")
				}
				c = sc.readRune()
				raw.WriteRune(c)
			}
		}
	} else {
		// triple-quoted string literal
		sc.readRune()
		raw.WriteRune(quote)
		sc.readRune()
		raw.WriteRune(quote)

		quoteCount := 0
		for {
			if sc.eof() {
				sc.error(val.pos, "unexpected EOF in string")
			}
			c := sc.readRune()
			raw.WriteRune(c)
			if c == quote {
				quoteCount++
				if quoteCount == 3 {
					break
				}
			} else {
				quoteCount = 0
			}
			if c == '\\' {
				if sc.eof() {
					sc.error(val.pos, "unexpected EOF in string")
				}
				c = sc.readRune()
				raw.WriteRune(c)
			}
		}
	}
	val.raw = raw.String()

	s, _, isByte, err := unquote(val.raw)
	if err != nil {
		sc.error(start, err.Error())
	}
	val.string = s
	if isByte {
		return BYTES
	} else {
		return STRING
	}
}