public bool InsertRuleWithANewSymbol(Grammar grammar)
{
for (var i = 0; i < NumberOfRetries; i++)
{
var existingLHSNonTerminal = grammar.GetRandomRule().Name.NonTerminal;
if (existingLHSNonTerminal == grammar.StartSymbol) continue;
var newLHSNonTerminal = grammar.GetNextAvailableProjectionName();
var typeOfExistingLHS = grammar.NonTerminalsTypeDictionary[existingLHSNonTerminal];
grammar.AddProjectionTypeToTypeDictionary(newLHSNonTerminal, typeOfExistingLHS);
//grammar.AddRule(new Rule(0, grammar.StartSymbol, new[] { newLHSNonTerminal, grammar.StartSymbol }, 0, 1));
// grammar.AddRule(new Rule(0, grammar.StartSymbol, new[] { newLHSNonTerminal }, 0, 0));
grammar.AddRule(new Rule(0, newLHSNonTerminal, new[] {existingLHSNonTerminal}, 0, 0));
return true;
}
return false;
}
public bool ChangeHeadOfRule(Grammar grammar)
{
for (var i = 0; i < NumberOfRetries; i++)
{
var rule = grammar.GetRandomRule();
if (!rule.IsInitialRule()) continue; //do not change complements of schematic rules. (push/pop)
if (rule.Production.Length > 1)
{
var newRule = new Rule(rule);
newRule.HeadPosition = (rule.HeadPosition + 1)%rule.Production.Length;
if (grammar.AreHeadRelationsConsistent(newRule))
{
grammar.DeleteRule(rule);
grammar.AddRule(newRule);
return true;
}
}
}
return false;
}
public bool AddMoveable(Grammar grammar)
{
for (var i = 0; i < NumberOfRetries; i++)
{
var rule = grammar.GetRandomRule();
//if movement symbol is LHS for some rule..
if (!grammar.Moveables.Contains(rule.Name.NonTerminal))
{
grammar.AddMoveable(rule.Name.NonTerminal);
return true;
}
}
return false;
}
public bool AddRuleToLandingSites(Grammar grammar)
{
for (var i = 0; i < NumberOfRetries; i++)
{
var rule = grammar.GetRandomRule();
//var movementSymbol = rule.NonComplementTerm;
//if movement symbol is LHS for some rule..
if (!grammar.LandingSites.Contains(rule.Name.NonTerminal))
{
grammar.AddNonTerminalToLandingSites(rule.Name.NonTerminal);
return true;
}
}
return false;
}
public bool ChangeComplementOfRule(Grammar grammar)
{
for (var i = 0; i < NumberOfRetries; i++)
{
var rule = grammar.GetRandomRule();
if (!rule.IsInitialRule()) continue; //do not change complements of schematic rules. (push/pop)
if (rule.Production.Length > 1)
{
rule.ComplementPosition = (rule.ComplementPosition + 1)%rule.Production.Length;
return true;
}
}
return false;
}
public bool DeleteRule(Grammar grammar)
{
var rule = grammar.GetRandomRule();
grammar.DeleteRule(rule);
return true;
}
