automaton

type Node struct {
	Final bool // final state
	Paths []Path
	Token Token
}

type Path struct {
	Exp    re.Regexp // regular expression used as transition condition
	Target *Node     // target node
}

type PreNode struct {
	Final bool              `json:"final"`
	Paths map[string]string `json:"paths"`
	Token Token             `json:"token,omitempty"`
}

type Token string