_LR0ItemSet _FillLRMove(_LR0ItemSet itemSet, string input, IProgress <CfgLRProgress> progress, _LR0ItemSet result = null)
{
if (null == result)
{
result = new _LR0ItemSet();
}
int i = 0;
foreach (var item in itemSet.Items)
{
if (null != progress)
{
progress.Report(new CfgLRProgress(CfgLRStatus.ComputingMove, i));
}
var next = item.Next;
if (!item.IsEnd)
{
if (Equals(next, input))
{
var lri = new _LR0Item(item.Left, item.Right, item.RightIndex + 1);
result.AddItem(lri);
}
}
++i;
}
_FillLRClosureInPlace(progress, result);
return(result);
}
static int _IndexOfItemSet(IEnumerable <_LR0ItemSet> sets, _LR0ItemSet set)
{
var i = 0;
foreach (var lris in sets)
{
if (lris.Equals(set))
{
return(i);
}
++i;
}
return(-1);
}
void _FillLRClosureInPlace(IProgress <CfgLRProgress> progress, _LR0ItemSet result)
{
var done = false;
while (!done)
{
done = true;
var l = new _LR0Item[result.Items.Count];
result.Items.CopyTo(l, 0);
for (var i = 0; i < l.Length; i++)
{
if (null != progress)
{
progress.Report(new CfgLRProgress(CfgLRStatus.ComputingClosure, i));
}
var item = l[i];
var next = item.Next;
if (!item.IsEnd || item.IsNil)
{
if (IsNonTerminal(next))
{
for (int jc = Rules.Count, j = 0; j < jc; ++j)
{
var r = Rules[j];
if (r.Left == next)
{
var lri = new _LR0Item(r, 0);
if (result.AddItem(lri))
{
done = false;
}
}
}
}
}
}
}
}
_LRFA _ToLRFA(IProgress <CfgLRProgress> progress)
{
if (null != progress)
{
progress.Report(new CfgLRProgress(CfgLRStatus.ComputingStates, 0));
}
var moves = new Dictionary <KeyValuePair <_LR0ItemSet, string>, _LR0ItemSet>();
// TODO: this takes a long time sometimes
var map = new Dictionary <_LR0ItemSet, _LRFA>();
// create an augmented grammar - add rule {start} -> [[StartId]]
var ss = StartSymbol;
var start = new CfgRule(GetAugmentedStartId(ss), new string[] { ss });
var cl = new _LR0ItemSet();
cl.AddItem(new _LR0Item(start, 0));
_FillLRClosureInPlace(progress, cl);
var lrfa = new _LRFA();
lrfa.Accept = cl;
var items = cl.Items.Count;
map.Add(cl, lrfa);
var done = false;
int oc;
while (!done)
{
done = true;
var arr = new _LR0ItemSet[map.Keys.Count];
map.Keys.CopyTo(arr, 0);
for (var i = 0; i < arr.Length; ++i)
{
var itemSet = arr[i];
foreach (var item in itemSet.Items)
{
var next = item.Next;
if (!item.IsEnd)
{
_LR0ItemSet n;
var key = new KeyValuePair <_LR0ItemSet, string>(itemSet, next);
if (!moves.TryGetValue(key, out n))
{
n = _FillLRMove(itemSet, next, progress);
moves.Add(key, n);
}
if (!map.ContainsKey(n))
{
done = false;
var npda = new _LRFA();
npda.Accept = n;
map.Add(n, npda);
items += n.Items.Count;
if (null != progress)
{
progress.Report(new CfgLRProgress(CfgLRStatus.ComputingConfigurations, items));
}
}
map[itemSet].Transitions[next] = map[n];
}
}
}
if (!done)
{
oc = map.Count;
if (null != progress)
{
progress.Report(new CfgLRProgress(CfgLRStatus.ComputingStates, oc));
}
}
}
return(lrfa);
}
