#include "Parsodus/lrtables/SLR1Itemset.h"

#include <algorithm>

namespace pds {
namespace lr {

SLR1Itemset::SLR1Itemset() : LR0ItemsetBase<SLR1Itemset>()
{}

SLR1Itemset::SLR1Itemset(std::shared_ptr<Rule> start) : LR0ItemsetBase<SLR1Itemset>(start)
{}

bool SLR1Itemset::needsFollow() {
    return true;
}

std::set<std::size_t> SLR1Itemset::getReduces(const Grammar& g, std::string lookahead) const {
    std::set<std::size_t> res;
    for (auto& item : m_items) {
        if (item.dotIdx >= item.rule->tail.size() && (*g.follow)(item.rule->head).count(lookahead)) {
            res.insert(std::find(g.rules.begin(), g.rules.end(), item.rule) - g.rules.begin());
        }
    }
    return res;
}

} /* lr  */ 
} /* pds  */