Exemplo n.º 1
0
Arquivo: lex.go Projeto: Xslxy/e8vm
func lexAsm8(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 '{':
		x.Next()
		return x.MakeToken(Lbrace)
	case '}':
		x.Next()
		return x.MakeToken(Rbrace)
	case '/':
		x.Next()
		return lex8.LexComment(x)
	case '"':
		return lex8.LexString(x, String, '"')
	}

	if isOperandChar(r) {
		return lexOperand(x)
	}

	x.Errorf("illegal char %q", r)
	x.Next()
	return x.MakeToken(lex8.Illegal)
}
Exemplo n.º 2
0
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)
}
Exemplo n.º 3
0
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
}
Exemplo n.º 4
0
func lexOperand(x *lex8.Lexer) *lex8.Token {
	if !isOperandChar(x.Rune()) {
		panic("incorrect operand start")
	}

	for {
		x.Next()
		if x.Ended() || !isOperandChar(x.Rune()) {
			break
		}
	}

	ret := x.MakeToken(Operand)
	if isKeyword(ret.Lit) {
		ret.Type = Keyword
	}
	return ret
}
Exemplo n.º 5
0
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)
}
Exemplo n.º 6
0
func lexOperator(x *lex8.Lexer, r rune) *lex8.Token {
	switch r {
	case ';':
		return x.MakeToken(Semi)
	case '{', '}', '(', ')', '[', ']', ',':
		/* do nothing */
	case '/':
		r2 := x.Rune()
		if r2 == '/' || r2 == '*' {
			return lex8.LexComment(x)
		} else if r2 == '=' {
			x.Next()
		}
	case '+', '-', '&', '|':
		r2 := x.Rune()
		if r2 == r || r2 == '=' {
			x.Next()
		}
	case '*', '%', '^', '=', '!', ':':
		r2 := x.Rune()
		if r2 == '=' {
			x.Next()
		}
	case '.':
		r2 := x.Rune()
		if r2 == '.' {
			x.Next()
			r3 := x.Rune()
			if r3 != '.' {
				x.Errorf("expect ..., but see ..")
				return x.MakeToken(Operator)
			}
			x.Next()
		}
	case '>', '<':
		r2 := x.Rune()
		if r2 == r {
			x.Next()
			r3 := x.Rune()
			if r3 == '=' {
				x.Next()
			}
		} else if r2 == '=' {
			x.Next()
		}
	default:
		return nil
	}

	return x.MakeToken(Operator)
}