/*
* 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.operator;
/**
* Enumerates unary (~, ^, *), binary (+, &, ++, ->, -, .) and nary (+, &, ++, ->) expression operators.
* @specfield op: (int->lone Expression) -> Expression
* @invariant all args: seq Expression, out: Expression | args->out in op => (out.children = args && out.op = this)
*/
public enum ExprOperator {
/** Relational union (+) operator. */
UNION { public String toString() { return "+"; } },
/** Relational intersection (&) operator. */
INTERSECTION { public String toString() { return "&"; } },
/** Relational override (++) operator. */
OVERRIDE { public String toString() { return "++"; } },
/** Relational product (->) operator. */
PRODUCT { public String toString() { return "->"; } },
/** Relational difference (-) operator. */
DIFFERENCE { public String toString() { return "-"; } },
/** Relational join (.) operator. */
JOIN { public String toString() { return "."; } },
/** Transpose (~) operator. */
TRANSPOSE { public String toString() { return "~";} },
/** Transitive closure (^) operator. */
CLOSURE { public String toString() { return "^";} },
/** Reflexive transitive closure (*) operator. */
REFLEXIVE_CLOSURE { public String toString() { return "*";} };
static final int unary = TRANSPOSE.index() | CLOSURE.index() | REFLEXIVE_CLOSURE.index();
static final int binary = ~unary;
static final int nary = UNION.index() | INTERSECTION.index() | OVERRIDE.index() | PRODUCT.index();
private final int index() { return 1<<ordinal(); }
/**
* Returns true if this is a unary operator.
* @return true if this is a unary operator.
*/
public final boolean unary() { return (unary & index())!=0; }
/**
* Returns true if this is a binary operator.
* @return true if this is a binary operator.
*/
public final boolean binary() { return (binary & index())!=0; }
/**
* Returns true if this is an nary operator.
* @return true if this is an nary operator.
*/
public final boolean nary() { return (nary & index())!=0; }
}