public GrammarProductionDatabase(IEnumerable <GrammarProduction> productions,
NonterminalSymbol startingSymbol)
{
var productionsPlusStart = productions.Union(
new GrammarProduction[] {
new GrammarProduction(NonterminalSymbol.StartingSymbol,
new SymbolString(new Symbol[] {
startingSymbol
}))
});
this.Productions = new HashSet <GrammarProduction>(productionsPlusStart).OrderBy(p => p).ToList().AsReadOnly();
this.Nonterminals = new HashSet <NonterminalSymbol>(this.Productions.Select(p => p.Head)).OrderBy(nt => nt).ToList().AsReadOnly();
this.StartingSymbol = NonterminalSymbol.StartingSymbol;
MapProductionsToNTSymbols();
ComputeNullableSymbols();
}
public bool IsNullable(NonterminalSymbol nt)
{
return(mNullableSymbols.Contains(nt));
}
public IReadOnlyList <GrammarProduction> this[NonterminalSymbol nt] {
get {
return(mProductionsByNTSymbol[nt]);
}
}
public GrammarProduction(NonterminalSymbol head, SymbolString body)
{
this.Head = head;
this.Body = body;
}
