/// <remarks>
/// The productions with a particular nonterminal D on their left sides
/// are called the alternatives of D.
/// </remarks>
IEnumerable<Production> GetAlternatives(NonTerminal D)
{
var list = new SortedSet<Production> ();
foreach (var p in this.Productions)
{
if (p.LeftPart == D) {
list.Add (p);
}
}
return list;
}
public Production (NonTerminal t, RewriteRule e)
{
this.LeftPart = t;
this.RightPart = e;
}
