4.3 Search.object

The object Search.object implements a demand driven search engine which supports recomputation, single, all, and best solution search and different kinds of output in the same way as the search engines in the previous section.

script

script(+ScriptP  
       +OrderP <= _  
       rcd:+RcdI <= 1)

Initializes the object for the script +Script (a unary procedure). If the optional argument +OrderP (a binary procedure) is given, the object uses a branch and bound strategy for best solution search.

+RcdI is the recomputation distance (see Section 4.2).

next

next(?Xs)

nextS

nextS(?Spaces)

nextP

nextP(?Ps)

returns a singleton list which contains the next solution. If no further solution exists, nil is returned. If the search is stopped by a message stop, stopped is returned.

The object releases its state immediately.

last

last(?Xs)

lastS

lastS(?Spaces)

lastP

lastP(?Ps)

returns a singleton list which contains the last solution. If no further solution exists, nil is returned. If the search is stopped by a message stop, stopped is returned.

The object releases its state immediately. If the object has been initialized for best solution search, the last solution is the best solution.

stop

stop

stops the search engine. The search engine can be restarted by next, nextS, nextP, last, lastS, and lastP.