/*****************************************************************************

* orlist.cc *

* *

* Description: OrList is a specialized class type which supports OR lists. *

* This file contains the OrList member functions, which pro- *

* vide the capability to undo previous choices, and select new *

* ones. *

* *

* Created by: David Rosenfeld *

* Date: 9/18/96 *

*****************************************************************************/

#include "clstepcore/complexSupport.h"

/**

* Check if we matched nm. We have two possibilities here: If we have a

* choice selected, we only check the selected choice. Say we're an OR

* between SimpleLists C and D, and nm = C. If choice = D, we can't check

* C. This is because we're already using this OR to match D, and it can

* not match C. If however, this OR doesn't have any choice selected (it

* = SATISFIED), we can check all our children. Since we don't need to

* have a particular choice selected (D), so long as we could be used to

* match C, we potentially have a match. (This all makes sense in the

* context of a sub w/ >1 super, in which case we build a combo-CList and

* may need to check if all sub-CLists matched the multi-sub, C.)

*/

bool OrList::hit( char * nm ) {

EntList * child = getChild( choice );

if( child ) {

// I.e., if we have a choice selected, check it only.

return ( child->hit( nm ) );

} else {

child = childList;

while( child ) {

if( child->viable > UNSATISFIED && child->hit( nm ) ) {

// See MultList::hit() on why we must skip UNSATs.

return true;

}

child = child->next;

}

}

return false;

}

/**

* Unmarks all the nodes of ents marked by the descendants of this.

*/

void OrList::unmarkAll( EntNode * ents ) {

EntList * child;

if( ( child = getChild( choice ) ) != NULL ) {

// choice = the last selected path which we'll now undo.

child->unmarkAll( ents );

}

}

/**

* Accepts the first choice of our childList which marks any unmarked

* nodes. If none of our current choices mark anything, choice is set to

* LISTEND. If choice was set to LISTEND before calling aC(), we reset

* choice to choice1, and search again.

*/

bool OrList::acceptChoice( EntNode * ents ) {

EntList * child;

if( choice == LISTEND ) {

choice = choice1;

}

child = getChild( choice );

while( child ) {

if( child->viable >= MATCHSOME && child->acceptChoice( ents ) ) {

// acceptChoice() returns true if we marked something.

return true;

}

child = child->next;

choice++;

}

// If we got here, we must have gotten to the end of the childList without

// finding a choice which marks something.

choice = LISTEND;

return false;

}