Multi-Way Component Attributes

Keywords:

CREF CRFA

Description:

In addition to Arrive and Leave p-points, some Components have further p-points which can become the ends of other Branches. For three-way Components (for example, TEE), the attribute CREF (Connection Reference) is used to show which Branch is connected to the free p-point. This is usually set automatically as a result of a CONNECT command, but it may also be set explicitly. For Components with more than three p-points (for example, CROSS), the attribute CRFA stores the names of up to 10 Branches which connect to this item. Although a Design Component element can possess a CREF or CRFA attribute, it is the Catalogue which controls whether the item can actually be connected to by other Branches.

Command Syntax:

>-- CREF --+--  <gid> --+-- HEAD --.
           |            |          |
           |            |-- TAIL --|
           |            |          |
           |            ‘----------+
           |                       |
           ‘-- NULREF -------------+-->

Querying:

>-- Query --+-- CREf --.
            |          |
            ‘-- CRFA --+-->