private Rule parseRule(string s, List<string> terminals, List<string> nonterminals)
{
Rule r = new Rule();
int leftLength = s.IndexOf(" -> ");
if (leftLength != 1)
throw new FormatException("Некорректный формат файла.");
r.Left.Sym = s.First().ToString();
if (s.Length == 6 && s[5] == 'e')
{
r.Right.Add(new EmptySymbol());
return r;
}
for (int i=5; i<s.Length; i++)
{
if (s[i] == 'e')
throw new FormatException("Некорректный формат файла.");
if (terminals.Contains(s[i].ToString()))
r.Right.Add(new Terminal(s[i].ToString()));
else
if (nonterminals.Contains(s[i].ToString()))
r.Right.Add(new Nonterminal(s[i].ToString()));
else
throw new FormatException("Некорректный формат файла.");
}
return r;
}
private List<Symbol> buildRightPartOfNewRule(List<Symbol> firstTerminals, List<Symbol> restOfString, Rule r)
{
List<Symbol> rightPart = new List<Symbol>(firstTerminals);
List<Symbol> symStrForNewNonterminal = new List<Symbol>(r.Right);
Nonterminal newNonterminal;
symStrForNewNonterminal.AddRange(restOfString);
newNonterminal = symbolStringToNonterminal(symStrForNewNonterminal);
if (!_nonterminalsForGrammarWithoutERules.Exists(A => A.Sym == newNonterminal.Sym))
_nonterminalsForGrammarWithoutERules.Add(newNonterminal);
rightPart.Add(newNonterminal);
return rightPart;
}
private void breakRuleForNonnullableGrammar(Rule r, Grammar g, out List<Nonterminal> firstVanishing, out List<Symbol> rest)
{
firstVanishing = new List<Nonterminal>();
rest = new List<Symbol>();
foreach (Symbol s in r.Right)
{
if (rest.Count > 0)
rest.Add(s);
else
if (g.isVanishingSymbol(s))
firstVanishing.Add((Nonterminal)s);
else
rest.Add(s);
}
}
public Rule(Rule r)
{
_left = new Nonterminal(r.Left);
_right = new List<Symbol>(r.Right);
}
private Rule createRuleWithNoFisrtVanishing(Rule rule, List<Symbol> rest)
{
Rule r = new Rule();
r.Left = new Nonterminal(rule.Left);
r.Right.AddRange(rest);
return r;
}
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<Rule> createNewRulesForFisrtVanishing(Rule rule, List<Nonterminal> firstVanishing, List<Symbol> rest)
{
List<Rule> rules= new List<Rule>();
List<Nonterminal> firstPart = new List<Nonterminal>(firstVanishing);
foreach (Nonterminal nt in firstVanishing)
{
firstPart[0] = _nonnullableNonterminalsMap[firstPart.First().Sym];
Rule r = new Rule();
r.Left = new Nonterminal(rule.Left);
r.Right.AddRange(firstPart);
r.Right.Concat(rest);
rules.Add(r);
firstPart.RemoveAt(0);
}
return rules;
}
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;
}