public Grammar(List<Nonterminal> nonterminals, List<Terminal> terminals, List<Rule> rules, Nonterminal distinguishedSymbol)
{
_nonterminals = new List<Nonterminal>(nonterminals);
_terminals = new List<Terminal>(terminals);
_rules = new List<Rule>(rules);
_distinguishedSymbol = distinguishedSymbol;
//findVanishingSymbols();
}
public Grammar(Grammar g)
{
_nonterminals = new List<Nonterminal>(g.Nonterminals);
_terminals = new List<Terminal>(g.Terminals);
_rules = new List<Rule>(g.Rules);
_distinguishedSymbol = new Nonterminal(g.DistinguishedSymbol);
_vanishingSymbols = new List<Nonterminal>(g.VanishingSymbols);
}
public Nonterminal(Nonterminal nt)
{
_sym = nt.Sym;
}
public Rule(Nonterminal left, List<Symbol> right)
{
_left = new Nonterminal(left);
_right = new List<Symbol>(right);
}
public Rule(Rule r)
{
_left = new Nonterminal(r.Left);
_right = new List<Symbol>(r.Right);
}
public Rule()
{
_left = new Nonterminal();
_right = new List<Symbol>();
}
private List<Symbol> nonterminalToSymbolString(Nonterminal nt)
{
return _nonterminalSymbolStringMap[nt.Sym];
}
private List<Rule> createRulesForLeftVanishing(List<Rule> curRules, Nonterminal left)
{
List<Rule> newRules = new List<Rule>();
foreach (Rule r in curRules)
{
Rule newRule = new Rule(r);
newRule.Left = _nonnullableNonterminalsMap[left.Sym];
newRules.Add(newRule);
}
return newRules;
}
private List<Nonterminal> bulidNonterminalsForNonnullableGrammar(Grammar g)
{
_nonnullableNonterminalsMap = new Dictionary<string, Nonterminal>();
List<Nonterminal> N = new List<Nonterminal>(g.Nonterminals);
foreach (Nonterminal vs in g.VanishingSymbols)
{
Nonterminal newNonterminal = new Nonterminal(String.Format("{0}*", vs.Sym));
N.Add(newNonterminal);
_nonnullableNonterminalsMap.Add(vs.Sym, newNonterminal);
}
return N;
}
private List<Rule> buildRulesForNonterminal(Nonterminal nonterminal, Grammar g)
{
List<Rule> newRules = new List<Rule>();
List<Rule> rules = new List<Rule>();
List<Symbol> symStr = nonterminalToSymbolString(nonterminal);
List<Symbol> firstTerminals = symStr.TakeWhile(ss => ss is Terminal).ToList();
foreach (Symbol nt in symStr)
if (nt is Nonterminal)
{
int ind = symStr.IndexOf(nt);
List<Symbol> restOfString = symStr.GetRange(ind + 1, symStr.Count - ind - 1);
foreach (Rule r in g.Rules)
{
if (r.Left.Sym == nt.Sym && !r.isERule())
{
Rule newRule = new Rule();
newRule.Left = new Nonterminal(nonterminal);
newRule.Right = buildRightPartOfNewRule(firstTerminals, restOfString, r);
newRules.Add(newRule);
}
}
if (ind == 0)
break;
}
if (firstTerminals.Count != 0)
newRules.Add(new Rule((Nonterminal)nonterminal, firstTerminals));
return newRules;
}
