static Lrfa _ToLrfa(CfgDocument cfg, IProgress <CfgLalr1Progress> progress)
{
if (null != progress)
{
progress.Report(new CfgLalr1Progress(CfgLalr1Status.ComputingStates, 0));
}
// TODO: this takes a long time sometimes
var map = new Dictionary <ICollection <LRItem>, Lrfa>(_LRItemSetComparer.Default);
// create an augmented grammar - add rule {start} -> [[StartId]]
var start = new CfgRule(cfg.GetAugmentedStartId(cfg.StartSymbol), new string[] { cfg.StartSymbol });
var cl = new HashSet <LRItem>();
cl.Add(new LRItem(start, 0));
_FillLRClosureInPlace(cfg, progress, cl);
var lrfa = new Lrfa(true, cl);
var items = cl.Count;
map.Add(cl, lrfa);
var done = false;
var oc = 0;
while (!done)
{
done = true;
var arr = map.Keys.ToArray();
for (var i = 0; i < arr.Length; ++i)
{
var itemSet = arr[i];
foreach (var item in itemSet)
{
var next = item.RightIndex < item.Rule.Right.Count ? item.Rule.Right[item.RightIndex] : null;
if (item.RightIndex < item.Rule.Right.Count)
{
var n = _FillLRMove(cfg, itemSet, next, progress);
if (!_ContainsItemSet(map.Keys, n))
{
done = false;
var npda = new Lrfa(true, n);
map.Add(n, npda);
items += n.Count;
if (null != progress)
{
progress.Report(new CfgLalr1Progress(CfgLalr1Status.ComputingConfigurations, items));
}
}
map[itemSet].Transitions[next] = map[n];
}
}
}
if (!done)
{
oc = map.Count;
if (null != progress)
{
progress.Report(new CfgLalr1Progress(CfgLalr1Status.ComputingStates, oc));
}
}
}
return(lrfa);
}
static CfgDocument _ToLRTransitionGrammar(CfgDocument cfg, Lrfa lrfa, IProgress <CfgLalr1Progress> progress)
{
var result = new CfgDocument();
var closure = new List <Lrfa>();
var itemSets = new List <ICollection <LRItem> >();
lrfa.FillClosure(closure);
foreach (var p in closure)
{
itemSets.Add(p.AcceptSymbol);
}
_LrtSymbol start = null;
int j = 0;
foreach (var p in closure)
{
if (null != progress)
{
progress.Report(new CfgLalr1Progress(CfgLalr1Status.CreatingLookaheadGrammar, j));
}
int si = itemSets.IndexOf(p.AcceptSymbol, _LRItemSetComparer.Default);
foreach (var item in p.AcceptSymbol)
{
if (0 == item.RightIndex)
{
var next = item.RightIndex < item.Rule.Right.Count ? item.Rule.Right[item.RightIndex] : null;
var rule = item.Rule;
if (item.RightIndex < item.Rule.Right.Count)
{
int dst = -1;
Lrfa dsts;
if (p.Transitions.ContainsKey(rule.Left))
{
dsts = p.Transitions[rule.Left];
dst = itemSets.IndexOf(dsts.AcceptSymbol, _LRItemSetComparer.Default);
}
_LrtSymbol left = new _LrtSymbol(si, rule.Left, dst);
if (null == start)
{
start = left;
}
var right = new List <string>();
var pc = p;
foreach (var sym in rule.Right)
{
int s1 = itemSets.IndexOf(pc.AcceptSymbol, _LRItemSetComparer.Default);
var pt = pc.Transitions[sym];
int s2 = itemSets.IndexOf(pt.AcceptSymbol, _LRItemSetComparer.Default);
_LrtSymbol n = new _LrtSymbol(s1, sym, s2);
right.Add(n.ToString());
pc = pt;
}
result.Rules.Add(new CfgRule(left.ToString(), right));
}
}
}
++j;
}
result.StartSymbol = start.ToString();
return(result);
}
