/*
* Kodkod -- Copyright (c) 2005-present, Emina Torlak
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package kodkod.ast;
import kodkod.ast.operator.ExprOperator;
import kodkod.ast.visitor.ReturnVisitor;
import kodkod.ast.visitor.VoidVisitor;
/**
* An {@link kodkod.ast.Expression expression} with one child.
*
* @specfield expression: Expression
* @specfield op: ExprOperator
* @invariant op.unary()
* @invariant children = 0->Expression
* @author Emina Torlak
*/
public final class UnaryExpression extends Expression {
private final Expression expression;
private final ExprOperator op;
private final int arity;
/**
* Constructs a new unary expression: op expression
*
* @ensures this.expression' = expression && this.op' = op
* @throws NullPointerException expression = null || op = null
* @throws IllegalArgumentException op in {TRANSPOSE, CLOSURE, REFLEXIVE_CLOSURE} && child.arity != 2
*/
UnaryExpression(ExprOperator op, Expression child) {
if (!op.unary()) {
throw new IllegalArgumentException("Not a unary operator: " + op);
}
if (child.arity()!=2) {
throw new IllegalArgumentException("Invalid arity: " + child + "::" + child.arity());
}
this.expression = child;
this.op = op;
this.arity = 2;
}
/**
* Returns the arity of this expression.
* @return this.arity
* @see kodkod.ast.Expression#arity()
*/
public int arity() {
return arity;
}
/**
* Returns this.expression.
* @return this.expression
*/
public Expression expression() {return expression;}
/**
* Returns this.op.
* @return this.op
*/
public ExprOperator op() {return op;}
/**
* {@inheritDoc}
* @see kodkod.ast.Expression#accept(kodkod.ast.visitor.ReturnVisitor)
*/
public <E, F, D, I> E accept(ReturnVisitor<E, F, D, I> visitor) {
return visitor.visit(this);
}
/**
* {@inheritDoc}
* @see kodkod.ast.Node#accept(kodkod.ast.visitor.VoidVisitor)
*/
public void accept(VoidVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
* @see kodkod.ast.Node#toString()
*/
public String toString() {
return op.toString() + expression.toString();
}
}