public BuilderHorizonSets(Productions <SYMBOL_ENUM, TREE_NODE> productions, int lookaheadWidth,
FirstSets <SYMBOL_ENUM> firstSets,
CoverSets <SYMBOL_ENUM> coverSets,
FollowSets <SYMBOL_ENUM> followSets)
: base(productions, lookaheadWidth)
{
this.firstSets = firstSets;
this.followSets = followSets;
this.coverSets = coverSets;
if (!coverSets.HasNonTerminals || lookaheadWidth != coverSets.LookaheadWidth)
{
throw new ArgumentException("Internal error.");
}
}
private void initFirstSets()
{
firstSets = new FirstSets <SYMBOL_ENUM>(lookaheadWidth);
foreach (SYMBOL_ENUM sym in terminals)
{
var set = new SymbolChunkSet <SYMBOL_ENUM>();
set.Add(SymbolChunk.Create(sym));
firstSets.Add(sym, set);
}
foreach (SYMBOL_ENUM sym in nonTerminals)
{
var set = new SymbolChunkSet <SYMBOL_ENUM>();
// iterate over all productions for this symbol except for error recovery productions
foreach (Production <SYMBOL_ENUM, TREE_NODE> prod in productions
.FilterByLhs(sym)
.Where(it => !it.RhsSymbols.Contains(syntaxErrorSymbol)))
{
// we take only terminals from front
IEnumerable <SYMBOL_ENUM> first_chunk = prod.RhsSymbols.TakeWhile(it => terminals.Contains(it));
int count = first_chunk.Count();
if (count >= lookaheadWidth) // we have more than enough
{
set.Add(SymbolChunk.Create(first_chunk.Take(lookaheadWidth)));
}
// we have less, but there was no more here
else if (count == prod.RhsSymbols.Count)
{
set.Add(SymbolChunk.Create(first_chunk));
}
}
firstSets.Add(sym, set);
}
}
public BuilderFollowSets(Productions <SYMBOL_ENUM, TREE_NODE> productions, int lookaheadWidth, FirstSets <SYMBOL_ENUM> firstSets)
: base(productions, lookaheadWidth)
{
this.firstSets = firstSets;
}
