/*
* 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.Multiplicity;
import kodkod.ast.visitor.ReturnVisitor;
import kodkod.ast.visitor.VoidVisitor;
/**
* A comprehension expression, e.g. { a: A, b: B | a.r = b }
*
* @specfield decls: Declarations
* @specfield formula: Formula
* @invariant arity = sum(decls.declarations().arity)
* @invariant children = 0->decls + 1->formula
* @author Emina Torlak
*/
public final class Comprehension extends Expression {
private final Decls decls;
private final Formula formula;
/**
* Constructs a comprehension expression with the specified decls
* and formula
*
* @ensures this.decls' = decls && this.formula' = formula
* @throws NullPointerException decls = null || formula = null
*/
Comprehension(Decls declarations, Formula formula) {
if (formula == null) throw new NullPointerException("null formula");
for(Decl decl : declarations) {
if (decl.variable().arity()>1 || decl.multiplicity()!=Multiplicity.ONE)
throw new IllegalArgumentException("Cannot have a higher order declaration in a comprehension: "+decl);
}
this.decls = declarations;
this.formula = formula;
}
/**
* @return this.formula
*/
public Formula formula() {return formula; }
/**
* @return this.decls
*/
public Decls decls() {return decls;}
/**
* Returns the arity of this comprehension expression, which is the sum
* of the arities of declared variables
*
* @return #this.decls
*/
public int arity() {
return decls.size();
}
/**
* {@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 "{ " + decls().toString() + " | " + formula().toString() + " }";
}
}