void MeltStates(State state)
{
bool ctx;
BitArray targets;
Symbol endOf;
for (Action action = state.firstAction; action != null; action = action.next)
{
if (action.target.next != null)
{
GetTargetStates(action, out targets, out endOf, out ctx);
Melted melt = StateWithSet(targets);
if (melt == null)
{
State s = NewState(); s.endOf = endOf; s.ctx = ctx;
for (Target targ = action.target; targ != null; targ = targ.next)
{
s.MeltWith(targ.state);
}
MakeUnique(s);
melt = NewMelted(targets, s);
}
action.target.next = null;
action.target.state = melt.state;
}
}
}
Melted firstMelted; // head of melted state list
Melted NewMelted(BitArray set, State state)
{
Melted m = new Melted(set, state);
m.next = firstMelted; firstMelted = m;
return(m);
}
public Melted(BitArray set, State state)
{
this.set = set;
this.state = state;
this.next = first;
first = this;
}
Melted StateWithSet(BitArray s)
{
for (Melted m = firstMelted; m != null; m = m.next)
{
if (Sets.Equals(s, m.set))
{
return(m);
}
}
return(null);
}
public DFA(Parser parser)
{
this.parser = parser;
tab = parser.tab;
errors = parser.errors;
trace = parser.trace;
firstState = null; lastState = null; lastStateNr = -1;
firstState = NewState();
firstMelted = null; firstComment = null;
ignoreCase = false;
dirtyDFA = false;
hasCtxMoves = false;
}
BitArray MeltedSet(int nr)
{
Melted m = firstMelted;
while (m != null)
{
if (m.state.nr == nr)
{
return(m.set);
}
else
{
m = m.next;
}
}
throw new FatalError("compiler error in Melted.Set");
}
public static BitArray Set(int nr)
{
Melted m = first;
while (m != null)
{
if (m.state.nr == nr)
{
return(m.set);
}
else
{
m = m.next;
}
}
throw new Exception("-- compiler error in Melted.Set");
}
public void GetTargetStates(out BitArray targets, out Symbol endOf, out bool ctx)
{
// compute the set of target states
targets = new BitArray(DFA.maxStates);
endOf = null;
ctx = false;
for (Target t = target; t != null; t = t.next)
{
int stateNr = t.state.nr;
if (stateNr <= DFA.lastSimState)
{
targets[stateNr] = true;
}
else
{
targets.Or(Melted.Set(stateNr));
}
if (t.state.endOf != null)
{
if (endOf == null || endOf == t.state.endOf)
{
endOf = t.state.endOf;
}
else
{
Console.WriteLine("Tokens {0} and {1} cannot be distinguished", endOf.name, t.state.endOf.name);
Errors.count++;
}
}
if (t.state.ctx)
{
ctx = true;
// The following check seems to be unnecessary. It reported an error
// if a symbol + context was the prefix of another symbol, e.g.
// s1 = "a" "b" "c".
// s2 = "a" CONTEXT("b").
// But this is ok.
// if (t.state.endOf != null) {
// Console.WriteLine("Ambiguous context clause");
// Errors.count++;
// }
}
}
}
Melted NewMelted(BitArray set, State state)
{
Melted m = new Melted(set, state);
m.next = firstMelted; firstMelted = m;
return m;
}
public DFA(Parser parser)
{
this.parser = parser;
tab = parser.tab;
errors = parser.errors;
trace = parser.trace;
firstState = null; lastState = null; lastStateNr = -1;
firstState = NewState();
firstMelted = null; firstComment = null;
ignoreCase = false;
dirtyDFA = false;
hasCtxMoves = false;
}
static void MeltStates(State state) {
bool changed, ctx;
BitArray targets;
Symbol endOf;
for (Action action = state.firstAction; action != null; action = action.next) {
if (action.target.next != null) {
action.GetTargetStates(out targets, out endOf, out ctx);
Melted melt = Melted.StateWithSet(targets);
if (melt == null) {
State s = NewState(); s.endOf = endOf; s.ctx = ctx;
for (Target targ = action.target; targ != null; targ = targ.next)
s.MeltWith(targ.state);
do {changed = MakeUnique(s);} while (changed);
melt = new Melted(targets, s);
}
action.target.next = null;
action.target.state = melt.state;
}
}
}
public Melted(BitArray set, State state) {
this.set = set; this.state = state;
this.next = first; first = this;
}
