public Negation(Token parent = null, string name = "")
{
this.parent = parent;
this.name = "NOT";
this.priority = Global.priorities["NOT"];
this.childrenCount = 1;
}
//public Operator() : base() { }
public Operator(Token parent = null, String name = "")
{
this.parent = parent;
this.name = name;
this.priority = Global.priorities[this.name];
this.childrenCount = 2;
}
//public Quantifier() : base() { }
public Quantifier(Token parent = null, string name = "")
{
this.parent = parent;
this.name = name;
this.priority = Global.priorities[this.name];
this.childrenCount = 2;
}
public Function(Token parent = null, String name = "", int argumentCount = 0)
{
this.parent = parent;
this.name = name;
this.childrenCount = argumentCount;
this.priority = Global.priorities["FUNCTION"];
this.arguments = new Token[argumentCount];
}
public override void setChild(int index, Token token)
{
if (index != 0)
throw new InvalidChildIndexException("Index: " + index);
this.child = token;
token.indexInParent = index;
token.parent = this;
}
public override void setChild(int index, Token token) {
switch (index)
{
case 0:
variable = token as Variable;
break;
case 1:
expression = token;
break;
default:
throw new Exception("Invalid child index: " + index);
}
token.indexInParent = index;
token.parent = this;
}
public override void setChild(int index, Token token)
{
switch (index)
{
case 0:
left = token;
break;
case 1:
right = token;
break;
default:
throw new InvalidChildIndexException("Index: " + index);
}
token.indexInParent = index;
token.parent = this;
}
public TokenTree simplify()
{
bool somethingDone;
do
{
somethingDone = false;
List<Token> tokens = ReverseBFS();
foreach (Token t in tokens)
{
if (t is Operator)
{
Token left = t.getChild(0);
Token right = t.getChild(1);
if(left is Variable && right is Variable)
{
if(left.name == right.name)
{
if(t.name == "AND" || t.name == "OR" || t.name == "IMPLIES")
{
somethingDone = true;
Token n = new Variable(name: left.name);
if (t.parent == null)
{
root = n;
}
else
{
t.parent.setChild(t.indexInParent, n);
}
}
}
}
}
}
} while (somethingDone);
return this;
}
public Variable(Token parent = null, string name = "")
{
this.parent = parent;
this.name = name;
this.childrenCount = 0;
}
public Token setParent(Token parent)
{
this.parent = parent;
return this;
}
public abstract void setChild(int index, Token token);
public TokenTree(Token root = null)
{
this.root = root;
}
public override void setChild(int index, Token token)
{
try
{
arguments[index] = token;
}
catch (Exception)
{
throw new InvalidChildIndexException("Index: " + index);
}
token.indexInParent = index;
token.parent = this;
}
public TokenTree convertAlternativeToConjunctions()
{
bool somethingDone;
do
{
somethingDone = false;
List<Token> tokens = ReverseBFS();
foreach (Token t in tokens)
{
if (t is Operator && t.name == "OR")
{
List<Token> left = new List<Token>();
List<Token> right = new List<Token>();
if(t.getChild(0) is Operator && t.getChild(0).name == "AND")
{
left.AddRange(getChildrenRecursively(t.getChild(0)));
}
else
{
left.Add(t.getChild(0));
}
if (t.getChild(1) is Operator && t.getChild(1).name == "AND")
{
right.AddRange(getChildrenRecursively(t.getChild(1)));
}
else
{
right.Add(t.getChild(1));
}
if (left.Count == 1 && right.Count == 1)
continue;
somethingDone = true;
List<Operator> alternatives = new List<Operator>();
foreach(Token l in left)
{
foreach(Token r in right)
{
Operator n = new Operator(name: "OR");
n.setChild(0, l);
n.setChild(1, r);
alternatives.Add(n);
}
}
Token mainAnd = new Operator(name: "AND");
Token current = mainAnd;
for(int i=0;i<alternatives.Count - 2;++i)
{
current.setChild(0, alternatives[i]);
current.setChild(1, new Operator(name:"AND"));
current = current.getChild(1);
}
current.setChild(0, alternatives[alternatives.Count - 2]);
current.setChild(1, alternatives[alternatives.Count - 1]);
if (t.parent == null)
root = mainAnd;
else
t.parent.setChild(t.indexInParent, mainAnd);
}
}
} while (somethingDone);
return this;
}
private List<Token> getChildrenRecursively(Token t)
{
List<Token> result = new List<Token>();
if (t.getChild(0) is Operator && t.getChild(0).name == "AND")
{
result.AddRange(getChildrenRecursively(t.getChild(0)));
}
else
result.Add(t.getChild(0));
if (t.getChild(1) is Operator && t.getChild(1).name == "AND")
{
result.AddRange(getChildrenRecursively(t.getChild(1)));
}
else
result.Add(t.getChild(1));
return result;
}
public TokenTree removeForallQuantifier()
{
bool somethingDone;
do
{
somethingDone = false;
List<Token> tokens = ReverseBFS();
foreach (Token t in tokens)
{
if (t is Quantifier && t.name == "FORALL")
{
somethingDone = true;
Token oldParent = t.parent;
Token expression = t.getChild(1);
if(oldParent == null)
{
root = expression;
expression.parent = null;
}
else
{
oldParent.setChild(t.indexInParent, expression);
}
}
}
} while (somethingDone);
return this;
}
public TokenTree removeExistsQuantifier()
{
bool somethingDone;
do
{
somethingDone = false;
List<Token> tokens = ReverseBFS();
foreach (Token t in tokens)
{
if (t is Quantifier && t.name == "EXISTS" && t.subtreeReplaced == false)
{
somethingDone = true;
Token current = t.parent;
List<Quantifier> parentQuantifiers = new List<Quantifier>();
while(current != null)
{
if(current is Quantifier && current.name == "FORALL")
parentQuantifiers.Add(current as Quantifier);
current = current.parent;
}
if(parentQuantifiers.Count > 0)
{
List<Token> subtree = t.getChild(1).BFS();
foreach (Token subtoken in subtree)
{
if (subtoken is Variable)
{
if(subtoken.name == t.getChild(0).name)
{
Token n = new Function(name: "F_" + t.getChild(0).name.ToUpper(), argumentCount: parentQuantifiers.Count);
for(int i=parentQuantifiers.Count - 1;i>=0;--i)
{
n.setChild(i, new Variable(name: parentQuantifiers[i].getChild(0).name));
}
subtoken.parent.setChild(subtoken.indexInParent, n);
}
}
}
}
else
{
List<Token> subtree = t.getChild(1).BFS();
string constantName = t.getChild(0).name.ToUpper();
foreach(Token subtoken in subtree)
{
if (subtoken is Variable && subtoken.name == t.getChild(0).name)
{
Token n = new Constant(name: constantName);
subtoken.parent.setChild(subtoken.indexInParent, n);
}
}
}
if (t.parent == null)
root = t.getChild(1);
else
t.parent.setChild(t.indexInParent, t.getChild(1));
}
}
} while (somethingDone);
return this;
}
public TokenTree restrainNegation()
{
bool somethingDone;
do {
somethingDone = false;
List<Token> tokens = ReverseBFS();
foreach (Token t in tokens)
{
if (t is Negation && t.getChild(0).isFinal() == false)
{
Token t_parent = t.parent;
Token c = t.getChild(0);
if(c is Negation)
{
somethingDone = true;
if (t_parent == null)
root = c.getChild(0);
else
t_parent.setChild(t.indexInParent, c.getChild(0));
// Console.WriteLine(serialize());
}
else if(c is Operator)
{
somethingDone = true;
if (c.name == "AND")
{
Token n = new Operator(name: "OR");
Token left = c.getChild(0);
Token right = c.getChild(1);
Token newLeft = new Negation();
Token newRight = new Negation();
newLeft.setChild(0, left.Clone());
newRight.setChild(0, right.Clone());
n.setChild(0, newLeft);
n.setChild(1, newRight);
if (t_parent == null)
{
root = n;
}
else
{
t_parent.setChild(t.indexInParent, n);
}
//Console.WriteLine(serialize());
}
else if (c.name == "OR")
{
Token n = new Operator(name: "AND");
Token left = c.getChild(0);
Token right = c.getChild(1);
Token newLeft = new Negation();
Token newRight = new Negation();
newLeft.setChild(0, left.Clone());
newRight.setChild(0, right.Clone());
n.setChild(0, newLeft);
n.setChild(1, newRight);
if (t_parent == null)
{
root = n;
}
else
{
t_parent.setChild(t.indexInParent, n);
}
//Console.WriteLine(serialize());
}
}
else if(c is Quantifier)
{
somethingDone = true;
if (c.name == "FORALL")
{
Token n = new Quantifier(name: "EXISTS");
Token left = c.getChild(0);
Token right = c.getChild(1);
Token newRight = new Negation();
newRight.setChild(0, right.Clone());
n.setChild(0, left);
n.setChild(1, newRight);
if (t_parent == null)
{
root = n;
}
else
{
t_parent.setChild(t.indexInParent, n);
}
} else if (c.name == "EXISTS")
{
Token n = new Quantifier(name: "FORALL");
Token left = c.getChild(0);
Token right = c.getChild(1);
Token newRight = new Negation();
newRight.setChild(0, right.Clone());
n.setChild(0, left);
n.setChild(1, newRight);
if (t_parent == null)
{
root = n;
}
else
{
t_parent.setChild(t.indexInParent, n);
}
}
}
}
}
} while (somethingDone);
return this;
}
public TokenTree replaceEquals()
{
List<Token> tokens = ReverseBFS();
foreach(Token t in tokens)
{
if(t is Operator && t.name == "EQUALS")
{
Token parent = t.parent;
Token left = t.getChild(0);
Token right = t.getChild(1);
Token n = new Operator(name: "AND");
Token newLeft = new Operator(name: "IMPLIES");
Token newRight = new Operator(name: "IMPLIES");
newLeft.setChild(0, left.Clone());
newLeft.setChild(1, right.Clone());
newRight.setChild(0, right.Clone());
newRight.setChild(1, left.Clone());
n.setChild(0, newLeft);
newLeft.parent = n;
n.setChild(1, newRight);
newRight.parent = n;
if (parent == null)
{
root = n;
}
else
{
parent.setChild(t.indexInParent, n);
}
}
}
return this;
}
public bool precedes(Token other)
{
return this.priority > other.priority;
}
public override void setChild(int index, Token token)
{
throw new InvalidChildIndexException("Index: " + index);
}
public Constant(Token parent = null, string name = "")
{
this.parent = parent;
this.name = name;
this.childrenCount = 0;
}