SymbolSet find(SymbolSet h)
{
if (h==null)
{
m_next = m_symbols.lahead;
m_symbols.lahead = this;
return this;
}
if (Equals(h,this))
return h;
return find(h.m_next);
}
static bool Equals(SymbolSet s,SymbolSet t)
{
if (s.m_set.Count!=t.m_set.Count)
return false;
IDictionaryEnumerator de = s.GetEnumerator();
IDictionaryEnumerator ee = t.GetEnumerator();
for (int pos=0; pos<s.Count; pos++)
{
de.MoveNext(); ee.MoveNext();
if (de.Key != ee.Key)
return false;
}
return true;
}
public void Print(SymbolSet x,string s)
{
Console.Write("Transition ("+m_ps.m_state+","+m_A.yytext+") "+s+" ");
x.Print();
}
public SymbolSet(SymbolSet s):this(s.m_symbols) { Add(s); }
public static void AddToRead(Transition a,SymbolSet s) { a.m_Read.Add(s); }
public static void AddToFollow(Transition a, SymbolSet s) { a.m_Follow.Add(s); }
public SymbolSet FirstOfRest(SymbolsGen syms)
{
if (follow!=null)
return follow;
follow = new SymbolSet(syms);
bool broke=false;
int n = m_prod.m_rhs.Count;
for (int j=m_pos+1;j<n;j++)
{
CSymbol s = (CSymbol)m_prod.m_rhs[j];
foreach (CSymbol a in s.m_first.Keys)
follow.CheckIn(a);
if (!s.IsNullable())
{
broke = true;
break;
}
}
if (!broke)
follow.Add(m_prod.m_lhs.m_follow);
follow = follow.Resolve();
return follow;
}
public static void AddToRead(Transition a, SymbolSet s)
{
a.m_Read.Add(s);
}
public SymbolSet m_follow; // for LR(0) phase: allow EOFSymbol
public bool AddFollow(SymbolSet map)
{ // CSymbol->bool : add contents of map to m_follow
bool r = false;
foreach(CSymbol a in map.Keys)
r |= m_follow.CheckIn(a);
return r;
}
public ObjectList m_prods = new ObjectList(); // Production: productions with this symbol as left side
public void AddStartItems(ParseState pstate,SymbolSet follows)
{
for (int pos=0;pos<m_prods.Count;pos++)
{
Production p = (Production)m_prods[pos];
pstate.MaybeAdd(new ProdItem(p, 0));
}
}
public CSymbol(SymbolsGen yyp) : base(yyp.m_lexer)
{
m_parser = yyp;
m_symtype = SymType.unknown;
m_prec = null;
m_prod = null;
m_refSymbol = null;
m_first = new SymbolSet(yyp);
m_follow = new SymbolSet(yyp);
}
public SymbolSet(SymbolSet s)
: this(s.m_symbols)
{
this.Add(s);
}
public static void AddToFollow(Transition a, SymbolSet s)
{
a.m_Follow.Add(s);
}
public void Add (SymbolSet s)
{
if (s==this)
return;
foreach (CSymbol k in s.Keys)
AddIn(k);
}
public void BuildLookback(Transition a)
{
SymbolsGen sg = a.m_ps.m_sgen;
if (m_lookAhead!=null)
return;
m_lookAhead = new SymbolSet(sg);
foreach (ParseState p in sg.m_symbols.m_states.Values)
{
Transition b = (Transition)p.m_transitions[m_prod.m_lhs.yytext];
if (b==null)
continue;
Path pa = new Path(p,m_prod.Prefix(m_prod.m_rhs.Count));
if (pa.valid && pa.Top == a.m_ps)
b.m_lookbackOf[this] = true;
}
}
public static SymbolSet operator+ (SymbolSet s,SymbolSet t)
{
SymbolSet r = new SymbolSet(s);
r.Add(t);
return r.Resolve();
}
public void Print(SymbolSet x, string s)
{
Console.Write("Transition (" + (object)this.m_ps.m_state + "," + this.m_A.yytext + ") " + s + " ");
x.Print();
}
