void LR0ItemCollectionFamily::build()
{
set<int> unhandled;
{
LR0ItemCollection col;
col.insert(LR0Item(0, 0));
int ID;
insertCollection(col, ID);
unhandled.insert(ID);
}
while (!unhandled.empty()) {
int ID = *unhandled.begin();
unhandled.erase(unhandled.begin());
for (auto sym : g_symolList) {
LR0ItemCollection newCol;
auto& col = ID2Collection[ID];
for (auto item : col) {
auto &body = getProductBody(item.productID);
if (item.pos < body.size() && body[item.pos] == sym) {
newCol.insert(LR0Item(item.productID, item.pos + 1));
}
}
if (newCol.empty()) continue;
int newID;
if (insertCollection(newCol, newID)) {
unhandled.insert(newID);
}
transMap[ID][sym] = newID;
}
}
removeCore();
}
void LR0ItemCollectionFamily::closureItem(LR0Item item, LR0ItemCollection& col)
{
if (!col.insert(item).second) return;
auto& body = getProductBody(item.productID);
if (item.pos >= body.size()) return;
if (!isNonTerm(body[item.pos])) return;
int pbegin, pend;
getNonTermProductRange(body[item.pos], pbegin, pend);
for (int pid = pbegin; pid < pend; ++pid) {
closureItem(LR0Item(pid, 0), col);
}
}
void CFG::constructCanonicalLR0Collection()
{
if(!augmented)
{
augmentGrammar();
}
canonicalLR0Collection.clear();
canonicalLR0Collection = vector<vector<LR0Item>>(
{
closure(
vector<LR0Item>(
{
LR0Item(
find_if(
p.begin(),
p.end(),
[this](const Production& pr)
{
return pr.left == s;
}
) - p.begin(),
0
)
})
)
});
bool updated = false;
vector<string> symbols = v;
symbols.insert(symbols.end(), t.begin(), t.end());
do
{
updated = false;
for(size_t i = 0; i < canonicalLR0Collection.size(); ++i)
{
for(size_t j = 0; j < symbols.size(); ++j)
{
vector<LR0Item> goToIX = goTo(canonicalLR0Collection[i], symbols[j]);
if(goToIX.size() != 0 && !in(goToIX, canonicalLR0Collection))
{
canonicalLR0Collection.push_back(goToIX);
updated = true;
}
}
}
}while(updated);
}
vector<LR0Item> CFG::closure(const vector<LR0Item>& is)
{
vector<LR0Item> js = is;
bool updated = false;
do
{
updated = false;
for(size_t i = 0; i < js.size(); ++i)
{
// A -> alpha . B beta
Production pr = p[js[i].productionIndex];
if(js[i].dotPosition < pr.right.size())
{
string b = pr.right[js[i].dotPosition];
if(in(b, v))
{
for(size_t j = 0; j < p.size(); ++j)
{
if(p[j].left == b)
{
bool exist = false;
for(size_t k = 0; k < js.size(); ++k)
{
if(js[k].productionIndex == j
&& js[k].dotPosition == 0)
{
exist = true;
break;
}
}
if(!exist)
{
js.push_back(LR0Item(j, 0));
updated = true;
}
}
}
}
}
}
}while(updated);
return js;
}
vector<LR0Item> CFG::goTo(const vector<LR0Item>& is, const string& x)
{
vector<LR0Item> js;
for(size_t i = 0; i < is.size(); ++i)
{
Production pr = p[is[i].productionIndex];
if(!(pr.right.size() == 1 && pr.right[0] == "")
&& is[i].dotPosition < pr.right.size()
&& pr.right[is[i].dotPosition] == x)
{
js.push_back(LR0Item(is[i].productionIndex, is[i].dotPosition + 1));
}
}
return closure(js);
}