content: /* 
   * 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 binary (&&, ||, =>, <=>) and nary (&&, ||) logical operators. 
   * @specfield op: (int->lone Formula) -> Formula
   * @invariant all args: seq Formula, out: Formula | args->out in op => (out.children = args && out.op = this)
   */
  public enum FormulaOperator {
      /** Logical AND operator. */      
      AND  		{ public String toString() { return "and"; } }, // [HASLab]
      /** Logical OR operator. */      
      OR 			{ public String toString() { return "or"; } }, // [HASLab]
      /** Logical bi-implication operator. */
      IFF 		{ public String toString() { return "iff"; } }, // [HASLab]
      /** Logical implication operator. */      
      IMPLIES 	{ public String toString() { return "implies"; } }; // [HASLab]
    
      static final int nary = (1<<AND.ordinal()) | (1<<OR.ordinal());
      
      /**
       * Returns true if this is an nary operator.
       * @return true if this is an nary operator
       */
      public final boolean nary() { return (nary & (1<<ordinal()))!=0; }
      
  
  }