import string
import vector
import set
import symbol

obj rule (Object) {
    var lhs: symbol::symbol
    var rhs: vector::vector<symbol::symbol>
    var position: int
    var lookahead: set::set<symbol::symbol>

    fun construct(): rule* {
        lhs.construct()
        rhs.construct()
        position = 0
        lookahead.construct()
    }
    fun copy_construct(old: rule*) {
        lhs.copy_construct(&rule->lhs)
        rhs.copy_construct(&rule->rhs)
        position = rule->position
        lookahead.copy_construct(&rule->lookahead)
    }
    fun operator=(other: rule) {
        destruct()
        copy_construct(&other)
    }
    fun destruct() {
        lhs.destruct()
        rhs.destruct()
        lookahead.destruct()
    }
}