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scnaner: implement scanning hexadecimal numbers

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This commit is contained in:
Fatih Arslan 2015-10-04 23:47:06 +03:00
parent 5d75c5a143
commit 0255587e95
2 changed files with 40 additions and 14 deletions
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30
scanner/scanner.go
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@ -132,8 +132,13 @@ func (s *Scanner) Scan() (tok token.Token) {
func (s *Scanner) scanNumber(ch rune) token.Token {
if ch == '0' {
// check hexadecimal or float
// ch = s.next()
// return token.ILLEGAL
ch = s.next()
if ch == 'x' || ch == 'X' {
ch = s.next()
s.scanHexadecimal(ch)
return token.NUMBER
}
}
s.scanMantissa(ch)
@ -147,6 +152,23 @@ func (s *Scanner) scanMantissa(ch rune) {
s.unread()
}
func (s *Scanner) scanHexadecimal(ch rune) {
found := false
// after "0x" or "0X"
for isHexadecimal(ch) {
ch = s.next()
found = true
}
if !found {
// only scanned "0x" or "0X"
s.err("illegal hexadecimal number")
}
s.unread()
}
// scanString scans a quoted string
func (s *Scanner) scanString() {
for {
@ -268,6 +290,10 @@ func isDecimal(ch rune) bool {
return '0' <= ch && ch <= '9'
}
func isHexadecimal(ch rune) bool {
return '0' <= ch && ch <= '9' || 'a' <= ch && ch <= 'f' || 'A' <= ch && ch <= 'F'
}
// isWhitespace returns true if the rune is a space, tab, newline or carriage return
func isWhitespace(ch rune) bool {
return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r'

24
scanner/scanner_test.go
View File

@ -111,18 +111,18 @@ func TestNumber(t *testing.T) {
{token.NUMBER, "07"},
{token.NUMBER, "042"},
{token.NUMBER, "01234567"},
// {token.NUMBER, "0x0"},
// {token.NUMBER, "0x1"},
// {token.NUMBER, "0xf"},
// {token.NUMBER, "0x42"},
// {token.NUMBER, "0x123456789abcDEF"},
// {token.NUMBER, "0x" + f100},
// {token.NUMBER, "0X0"},
// {token.NUMBER, "0X1"},
// {token.NUMBER, "0XF"},
// {token.NUMBER, "0X42"},
// {token.NUMBER, "0X123456789abcDEF"},
// {token.NUMBER, "0X" + f100},
{token.NUMBER, "0x0"},
{token.NUMBER, "0x1"},
{token.NUMBER, "0xf"},
{token.NUMBER, "0x42"},
{token.NUMBER, "0x123456789abcDEF"},
{token.NUMBER, "0x" + f100},
{token.NUMBER, "0X0"},
{token.NUMBER, "0X1"},
{token.NUMBER, "0XF"},
{token.NUMBER, "0X42"},
{token.NUMBER, "0X123456789abcDEF"},
{token.NUMBER, "0X" + f100},
// {token.FLOAT, "0."},
// {token.FLOAT, "1."},
// {token.FLOAT, "42."},