(* Copyright (c) 2008, Adam Chlipala
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - The names of contributors may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *)

signature SEARCH = sig

    datatype ('state, 'abort) result =
             Return of 'abort
           | Continue of 'state

    type ('data, 'state, 'abort) mapfolder =
         'data -> 'state -> ('data * 'state, 'abort) result

    type ('context, 'data, 'state, 'abort) mapfolderB =
         'context -> 'data -> 'state -> ('data * 'state, 'abort) result

    val return2 : 'data -> 'state -> ('data * 'state, 'abort) result

    val map : ('state1, 'abort) result
              * ('state1 -> 'state2)
              -> ('state2, 'abort) result

    val map2 : ('state2 -> ('state1 * 'state2, 'abort) result)
               * ('state1 -> 'state1')
               -> ('state2 -> ('state1' * 'state2, 'abort) result)

    val bind : ('state1, 'abort) result
               * ('state1 -> ('state2, 'abort) result)
               -> ('state2, 'abort) result

    val bind2 : ('state2 -> ('state1 * 'state2, 'abort) result)
               * ('state1 -> 'state2 -> ('state1' * 'state2, 'abort) result)
               -> ('state2 -> ('state1' * 'state2, 'abort) result)

    val bindP : (('state11 * 'state12) * 'state2, 'abort) result
                * ('state11 -> 'state2 -> ('state11 * 'state2, 'abort) result)
                -> (('state11 * 'state12) * 'state2, 'abort) result

end