public static void BuildIncludes( Transition t) // code improved by Wayne Kelly
{
t.m_Follow = new SymbolSet (t.m_ps.m_sgen);
foreach (Production p in t.m_A.m_prods)
{
for ( int i = p.m_rhs.Count - 1; i >= 0; i--)
{
CSymbol s = ( CSymbol)p.m_rhs[i];
if (s.m_symtype == CSymbol. SymType .nonterminal)
{
ParseState ps;
if (i > 0)
ps = new Path(t.m_ps, p.Prefix(i)).Top;
else
ps = t.m_ps;
Transition b = ( Transition) ps.m_transitions[s.yytext];
b.m_includes[t] = true;
}
if (!s.IsNullable())
break;
}
}
}
public static void BuildLookback(Transition t)
{
foreach (ParserReduce pr in t.m_reduce.Values)
pr.BuildLookback(t);
}
public static void Final(Transition t)
{
t.m_DR.AddIn(t.m_ps.m_sgen.m_symbols.EOFSymbol);
}
public static void BuildReads(Transition t)
{
t.m_Read = new SymbolSet(t.m_ps.m_sgen);
ParseState ps = t.m_A.Next(t.m_ps);
if (ps==null)
return;
foreach (Transition b in ps.m_transitions.Values)
if (b.m_A.IsNullable())
t.m_reads[b] = true;
}
public static void AddToFollow(Transition a, SymbolSet s) { a.m_Follow.Add(s); }
SymbolSet m_Follow; // ditto
public static void BuildDR(Transition t)
{
SymbolsGen sg = t.m_ps.m_sgen;
t.m_DR = new SymbolSet(sg);
if (t.m_next==null)
return;
foreach (Transition u in t.m_next.m_next.m_transitions.Values)
if (u.m_next!=null)
if (u.m_A.m_symtype==CSymbol.SymType.terminal || u.m_A.m_symtype==CSymbol.SymType.eofsymbol)
t.m_DR.AddIn(u.m_A);
}
public static SymbolSet Follow(Transition a) { return a.m_Follow; }
public static void BuildParseTable(Transition t)
{
Symbols syms = t.m_ps.m_sgen.m_symbols;
ParsingInfo pi = t.ParsingInfo;
ParserReduce red = null;
foreach (ParserReduce pr in t.m_reduce.Values)
{
if (t.m_ps.m_sgen.m_lalrParser?
pr.m_lookAhead.Contains(t.m_A):
pr.m_prod.m_lhs.m_follow.Contains(t.m_A))
{
if (red!=null)
syms.erh.Error(new CSToolsException(12,string.Format("reduce/reduce conflict {0} vs {1}",red.m_prod.m_pno,pr.m_prod.m_pno)+
string.Format(" state {0} on {1}",t.m_ps.m_state,t.m_A.yytext)));
red = pr;
}
// else
// t.Print(pr.m_lookAhead,"discarding reduce ("+pr.m_prod.m_pno+") LA ");
}
if (t.m_next!=null && t.m_A!=syms.EOFSymbol)
{
if (red==null)
pi.m_parsetable[t.m_ps.m_state] = t.m_next;
else if (t.m_A.ShiftPrecedence(red.m_prod,t.m_ps))
pi.m_parsetable[t.m_ps.m_state] = t.m_next;
else
pi.m_parsetable[t.m_ps.m_state] = red;
}
else if (red!=null)
pi.m_parsetable[t.m_ps.m_state] = red;
}
public static SymbolSet DR(Transition a) { return a.m_DR; }
public static SymbolSet Read(Transition a) { return a.m_Read; }
public static Hashtable includes(Transition a) { return a.m_includes; }
internal Hashtable m_lookbackOf = new Hashtable(); // ParserReduce->bool
public static Hashtable reads(Transition a) { return a.m_reads; }
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 void BuildLA(Transition t)
{
foreach (ParserReduce pr in t.m_lookbackOf.Keys)
pr.m_lookAhead.Add(t.m_Follow);
}
public static void AddToRead(Transition a,SymbolSet s) { a.m_Read.Add(s); }
public static void BuildParseTable(Transition t)
{
YyParser syms = t.m_ps.m_sgen.m_symbols;
ParsingInfo pi = t.ParsingInfo;
ParserReduce red = null;
foreach (ParserReduce pr in t.m_reduce.Values)
{
if (t.m_ps.m_sgen.m_lalrParser?
pr.m_lookAhead.Contains(t.m_A):
pr.m_prod.m_lhs.m_follow.Contains(t.m_A))
{
if (red!=null)
syms.erh.Error(new CSToolsException(12,string.Format("reduce/reduce conflict {0} vs {1}",red.m_prod.m_pno,pr.m_prod.m_pno)+
string.Format(" state {0} on {1}",t.m_ps.m_state,t.m_A.yytext)));
red = pr;
}
// else
// t.Print(pr.m_lookAhead,"discarding reduce ("+pr.m_prod.m_pno+") LA ");
}
if (t.m_next!=null && t.m_A!=syms.EOFSymbol)
{
if (red == null)
pi.m_parsetable[t.m_ps.m_state] = t.m_next;
else
{
int p = Precedence.Check(t.m_A, red.m_prod, 0); // 4.7m
if (p > 0)
{
pi.m_parsetable[t.m_ps.m_state] = t.m_next;
t.m_reduce.Remove(red.m_prod);
}
else if (p < 0)
{
pi.m_parsetable[t.m_ps.m_state] = red;
t.m_next = null;
}
else
switch (t.m_A.ShiftPrecedence(red.m_prod, t.m_ps)) // 4.5h
{
case Precedence.PrecType.left:
pi.m_parsetable[t.m_ps.m_state] = t.m_next;
t.m_reduce.Remove(red.m_prod);
break;
case Precedence.PrecType.right:
pi.m_parsetable[t.m_ps.m_state] = red;
t.m_next = null;
break;
}
}
}
else if (red != null)
pi.m_parsetable[t.m_ps.m_state] = red;
}
public static void BuildIncludes(Transition t)
{
t.m_Follow = new SymbolSet(t.m_ps.m_sgen);
foreach (ParseState ps in t.m_ps.m_sgen.m_symbols.m_states.Values)
foreach (Production p in t.m_ps.m_sgen.prods)
{
Transition b = (Transition)ps.m_transitions[p.m_lhs.yytext];
if (b==null)
continue;
for (int i=p.m_rhs.Count-1;i>=0;i--)
{
CSymbol s = (CSymbol)p.m_rhs[i];
if (s==t.m_A)
{
if (i==0 && b.m_ps==t.m_ps)
{
t.m_includes[b] = true;
break;
}
if (new Path(b.m_ps,p.Prefix(i)).Top == t.m_ps)
{
t.m_includes[b] = true;
break;
}
}
if (!s.CouldBeEmpty())
break;
}
}
}
