PCE version 4C man_modulenamespaceid_tablemodified current_idOIxNclass/relationN referenceC hash_tablerefersizeOIxaIsNM.relation.S.createCman_method_card identifiermodule last_modifiednamesummary descriptionsee_alsoinherit diagnosticsdefaultsbugsOIxNM.relation.S.createRICdateOIx,}ENcreatenCstringOIxInvokes ->forwards to itself. This method is activated when the constraint object this relation is referred from is initialised.nnnnnsNM.relation.S.backwardsOIxNM.relation.S.backwardsRIOIx,M2wN backwardsnOIxICalled after `to' has changed. Its task is to update `from' accordingly.nnnnnsNM.relation.S.forwardsOI xNM.relation.S.forwardsRIOI x,M4ONforwardsnOI xCalled after `from' has changed. Its task is to update `to' accordingly. If ->create has not been redefined, this method is also called when the constraint object is established.nnnnnsN C.relationCman_class_card identifiermodule last_modifiednamesummary descriptionsee_alsoinherituser_interfacebugsOI xN C.relationRIOI x.KNrelationnOIxA `relation' describes the reusable part of a constraint object. Class relation may be subclassed to define new relations. Subclasses normally redefine ->create, ->forward and/or ->backwards. The current system contains two types of relations, two of which are strictly between graphicals and one general. They are: # class spatial Spatial relation between two graphicals # class identity Identity of attributes. New relations may be defined as user-defined subclasses of this class. A relation should define the methods: # ->create Called when the relation is established # ->forwards Called if the `constraint <-from' side changes. # ->backwards Called if the `constraint <-to' side changes.CchainsizeOIxIeN$class/constraint$C.constraintXnnnXuCnumberOIxx