public FirstSets <SYMBOL_ENUM> ComputeFirstSets(ref Dictionary <Production <SYMBOL_ENUM, TREE_NODE>, Dictionary <int, SymbolChunkSet <SYMBOL_ENUM> > > precomputedRhsFirsts)
{
initFirstSets();
while (expandFirstSets())
{
;
}
precomputedRhsFirsts = new Dictionary <Production <SYMBOL_ENUM, TREE_NODE>, Dictionary <int, SymbolChunkSet <SYMBOL_ENUM> > >();
foreach (Production <SYMBOL_ENUM, TREE_NODE> prod in productions.ProductionsWithNoErrorSymbol())
{
var rhs_firsts = new Dictionary <int, SymbolChunkSet <SYMBOL_ENUM> >();
// =, because we could read all symbols
for (int i = 0; i <= prod.RhsSymbols.Count; ++i)
{
rhs_firsts.Add(i, firstSets.GetFirstsOf(prod.RhsSymbols.Skip(i), terminals, syntaxErrorSymbol, lookaheadWidth));
}
precomputedRhsFirsts.Add(prod, rhs_firsts);
}
return(firstSets);
}
private void bootstrapFromFirstSets(SYMBOL_ENUM symbol)
{
SymbolChunkSet <SYMBOL_ENUM> follow_set = followSets[symbol];
// in all RHS of productions find our symbol
foreach (Production <SYMBOL_ENUM, TREE_NODE> prod in productions.ProductionsWithNoErrorSymbol())
{
for (int i = 0; i < prod.RhsSymbols.Count(); ++i)
{
// we are above our symbol on RHS of the production
if (prod.RhsSymbols[i].Equals(symbol))
{
// get first set of what can happen AFTER our symbol -- this will be follow set by definition
SymbolChunkSet <SYMBOL_ENUM> chunk_set
= firstSets.GetFirstsOf(prod.RhsSymbols.Skip(i + 1), terminals, syntaxErrorSymbol, lookaheadWidth);
{
SymbolChunkSet <SYMBOL_ENUM> tmp = new SymbolChunkSet <SYMBOL_ENUM>();
// add LHS non-terminal at the end of too short chunks as generator
// because what follows LHS also follows given symbol
foreach (SymbolChunk <SYMBOL_ENUM> chunk in chunk_set.Chunks)
{
if (chunk.Count < lookaheadWidth)
{
tmp.Add(chunk.Append(prod.LhsNonTerminal));
}
else
{
tmp.Add(chunk);
}
}
chunk_set = tmp;
}
if (chunk_set.IsEmpty)
{
chunk_set.Add(SymbolChunk.Create(prod.LhsNonTerminal));
}
follow_set.Add(chunk_set);
}
}
}
}
private void bootstrapFromFirstSets(SYMBOL_ENUM symbol)
{
SymbolChunkSet <SYMBOL_ENUM> current_set = horizonSets[symbol];
// in all RHS of productions find our symbol
foreach (Production <SYMBOL_ENUM, TREE_NODE> prod in productions.Entries)
{
if (symbol.Equals(prod.LhsNonTerminal) || coverSets[symbol].Contains(SymbolChunk.Create(prod.LhsNonTerminal)))
{
continue;
}
for (int i = 0; i < prod.RhsSymbols.Count(); ++i)
{
// we are on our symbol on RHS of the production
if (prod.RhsSymbols[i].Equals(symbol))
{
// get first set of what can happen AFTER our symbol -- this will be our horizon
SymbolChunkSet <SYMBOL_ENUM> src_set = firstSets.GetFirstsOf(prod.RhsSymbols.Skip(i + 1), terminals, syntaxErrorSymbol, lookaheadWidth);
SymbolChunkSet <SYMBOL_ENUM> chunk_set = new SymbolChunkSet <SYMBOL_ENUM>();
// add follow set at the end of too short chunks
foreach (SymbolChunk <SYMBOL_ENUM> chunk in src_set.Chunks)
{
if (chunk.Count < lookaheadWidth)
{
chunk_set.Add(SymbolChunkSet.MultiConcat(chunk, followSets[prod.LhsNonTerminal], lookaheadWidth));
}
else
{
chunk_set.Add(chunk);
}
}
if (chunk_set.IsEmpty)
{
chunk_set.Add(followSets[prod.LhsNonTerminal]);
}
current_set.Add(chunk_set);
}
}
}
}
