special = iota
	literal
	operator
	keyword
)

func tokenclass(tok token.Token) int {
	switch {
	case tok.IsLiteral():
		return literal
	case tok.IsOperator():
		return operator
	case tok.IsKeyword():
		return keyword
	}
	return special
}

type elt struct {
	tok   token.Token
	lit   string
	class int
}

var tokens = []elt{
	// Special tokens