public static void ConvertToStates(Node p, Symbol sym)
{
curGraph = p; curSy = sym;
if (Node.DelGraph(curGraph))
{
Parser.SemErr("token might be empty");
}
NumberNodes(curGraph, firstState);
FindTrans(curGraph, true, new BitArray(Node.nodes.Count));
}
static void NumberNodes(Node p, State state)
{
/* Assigns a state n.state to every node n. There will be a transition from
* n.state to n.next.state triggered by n.val. All nodes in an alternative
* chain are represented by the same state.
*/
if (p == null)
{
return;
}
if (p.state != null)
{
return; // already visited;
}
if (state == null)
{
state = NewState();
}
p.state = state;
if (Node.DelGraph(p))
{
state.endOf = curSy;
}
switch (p.typ)
{
case Node.clas:
case Node.chr:
{
NumberNodes(p.next, null);
break;
}
case Node.opt:
{
NumberNodes(p.next, null);
NumberNodes(p.sub, state);
break;
}
case Node.iter:
{
NumberNodes(p.next, state);
NumberNodes(p.sub, state);
break;
}
case Node.alt:
{
NumberNodes(p.sub, state);
NumberNodes(p.down, state);
break;
}
}
}
static void GetSingles(Node p, ArrayList singles) {
if (p == null) return; // end of graph
if (p.typ == Node.nt) {
if (p.up || Node.DelGraph(p.next)) singles.Add(p.sym);
} else if (p.typ == Node.alt || p.typ == Node.iter || p.typ == Node.opt) {
if (p.up || Node.DelGraph(p.next)) {
GetSingles(p.sub, singles);
if (p.typ == Node.alt) GetSingles(p.down, singles);
}
}
if (!p.up && Node.DelNode(p)) GetSingles(p.next, singles);
}
public static void CompDeletableSymbols() {
bool changed;
do {
changed = false;
foreach (Symbol sym in Symbol.nonterminals)
if (!sym.deletable && sym.graph != null && Node.DelGraph(sym.graph)) {
sym.deletable = true; changed = true;
}
} while (changed);
foreach (Symbol sym in Symbol.nonterminals)
if (sym.deletable) Console.WriteLine(" {0} deletable", sym.name);
}
static void CompFollow(Node p) {
while (p != null && !visited[p.n]) {
visited[p.n] = true;
if (p.typ == Node.nt) {
BitArray s = First(p.next);
p.sym.follow.Or(s);
if (Node.DelGraph(p.next))
p.sym.nts[curSy.n] = true;
} else if (p.typ == Node.opt || p.typ == Node.iter) {
CompFollow(p.sub);
} else if (p.typ == Node.alt) {
CompFollow(p.sub); CompFollow(p.down);
}
p = p.next;
}
}
public static BitArray Expected(Node p, Symbol curSy, int outmost) {
BitArray s = First(p);
if (Node.DelGraph(p)) s.Or(curSy.follow);
return s;
}
