func lexG8(x *lex8.Lexer) *lex8.Token {
r := x.Rune()
if x.IsWhite(r) {
panic("incorrect token start")
}
switch r {
case '\n':
x.Next()
return x.MakeToken(Endl)
case '"':
return lex8.LexString(x, String, '"')
case '\'':
return lex8.LexString(x, Char, '\'')
}
if lex8.IsDigit(r) {
return lexNumber(x)
} else if isLetter(r) {
return lexIdent(x)
}
// always make progress at this point
x.Next()
t := lexOperator(x, r)
if t != nil {
return t
}
x.Errorf("illegal char %q", r)
return x.MakeToken(lex8.Illegal)
}
func lexNumber(x *lex8.Lexer) *lex8.Token {
// TODO: lex floating point as well
start := x.Rune()
if !lex8.IsDigit(start) {
panic("not starting with a number")
}
x.Next()
r := x.Rune()
if start == '0' && r == 'x' {
x.Next()
for lex8.IsHexDigit(x.Rune()) {
x.Next()
}
} else {
for lex8.IsDigit(x.Rune()) {
x.Next()
}
}
return x.MakeToken(Int)
}
func lexIdent(x *lex8.Lexer) *lex8.Token {
r := x.Rune()
if !isLetter(r) {
panic("must start with letter")
}
for {
x.Next()
r := x.Rune()
if !isLetter(r) && !lex8.IsDigit(r) {
break
}
}
ret := x.MakeToken(Ident)
return ret
}