/// <summary>
/// Calculates the first sets of all grammaticals of the given <paramref name="grammar"/>.
/// </summary>
/// <param name="grammar">The grammaticals which are to examen, are in this grammar.</param>
/// <param name="epsilon_grammaticals">Set of the epsilon capable grammaticals of the given
/// <paramref name="grammar"/>. (see <see cref="EpsilonGrammaticals"/>)</param>
/// <returns>The first sets for all the grammaticals of the given <paramref name="grammar"/>.</returns>
/// <exception cref="ArgumentNullException"> if any of the parameters is <c>null</c>.</exception>
public static IDictionary<GrammaticalSymbol, ISet<TerminalSymbol>> Build(
ExtendedGrammar grammar, ISet<GrammaticalSymbol> epsilon_grammaticals)
{
if( grammar == null )
throw new ArgumentNullException("grammar");
if( epsilon_grammaticals == null )
throw new ArgumentNullException("epsilon_grammaticals");
// Relation matrix
var f_plus = new RelationMatrix(grammar.Terminals.Count + grammar.Grammaticals.Count);
RelationMatrix.TransitiveClosure(F_Relation(grammar), f_plus);
// Build the first_sets
var first_sets = new Dictionary<GrammaticalSymbol, ISet<TerminalSymbol>>();
foreach( var gr in grammar.Grammaticals )
{
int gr_index = grammar.GlobalIndexOf(gr);
// Put all terminals being in relation with gr into gr's first_set
var first_set = new HashSet<TerminalSymbol>();
foreach( var tr in grammar.Terminals )
if( f_plus[gr_index, grammar.GlobalIndexOf(tr)] )
first_set.Add(tr);
if( epsilon_grammaticals.Contains(gr) )
first_set.Add(EpsilonSymbol.Instance);
first_sets.Add(gr, first_set);
}
return first_sets;
}
/// <summary>
/// Calculates the follow sets of all grammaticals of the given <paramref name="grammar"/>.
/// </summary>
/// <param name="grammar">The grammaticals which are to examen, are in this grammar.</param>
/// <param name="epsilon_grammaticals">Set of the epsilon capable grammaticals of the given
/// <paramref name="grammar"/>. (see <see cref="EpsilonGrammaticals"/>)</param>
/// <returns>The first sets for all the grammaticals of the given <paramref name="grammar"/>.</returns>
/// <exception cref="ArgumentNullException"> if any of the parameters is <c>null</c>.</exception>
public static IDictionary<GrammaticalSymbol, ISet<TerminalSymbol>> Build(
ExtendedGrammar grammar, ISet<GrammaticalSymbol> epsilon_grammaticals)
{
if( grammar == null )
throw new ArgumentNullException("grammar");
if( epsilon_grammaticals == null )
throw new ArgumentNullException("epsilon_grammaticals");
int symbol_count = grammar.Terminals.Count + grammar.Grammaticals.Count;
var f_star = new RelationMatrix(symbol_count);
RelationMatrix.TransitiveClosure(FirstSets.F_Relation(grammar), f_star);
RelationMatrix.ReflexiveClosure(f_star);
var l_star = new RelationMatrix(symbol_count);
RelationMatrix.TransitiveClosure(L_Relations(grammar, epsilon_grammaticals), l_star);
RelationMatrix.ReflexiveClosure(l_star);
var b = B_Relation(grammar, epsilon_grammaticals);
var tmp = new RelationMatrix(symbol_count);
var lbf = new RelationMatrix(symbol_count);
RelationMatrix.WharshallAlg(l_star, b, tmp);
RelationMatrix.WharshallAlg(tmp, f_star, lbf);
// Build the follow_sets
var follow_sets = new Dictionary<GrammaticalSymbol, ISet<TerminalSymbol>>();
foreach( var gr in grammar.Grammaticals )
{
int gr_index = grammar.GlobalIndexOf(gr);
// Put all terminals being in relation with gr into gr's follow_set
var follow_set = new HashSet<TerminalSymbol>();
foreach( var tr in grammar.Terminals )
if( lbf[gr_index, grammar.GlobalIndexOf(tr)] )
follow_set.Add(tr);
follow_sets.Add(gr, follow_set);
}
return follow_sets;
}