# Registry¶

A Registry is used to maintain a list of categories (subclasses) for a given base_class of Component, and to ensure that the name of every Component created in each of those categories is unique. If an item is created with the same name as one already in the Registry, its name is appended with a hyphenated index (e.g., name-n) that is incremented for each new item assigned the same base name, as described in greater detail below.

## Naming¶

Every object in PsyNeuLink has a name attribute, that is a string used to refer to it in printouts and display. The name of a object can be specified in the name argument of its constructor. An object’s name can be reassigned, but this should be done with caution, as other objects may depend on its name.

### Default Names¶

If the name of an object is not specified in its constructor, a default name is assigned. Some classes of objects use class-specific conventions for default names (see individual classes for specifics). Otherwise, the default name is handled by the Registry, which assigns a default name based on the name of the class, with a hyphenated integer suffix (<object class name>-n), beginning with ‘0’, that is incremented for each additional object of that type requiring a default name. For example, the first TransferMechanism to be constructed without specifying its name will be assigned the name ‘TransferMechanism-0’, the next ‘TransferMechanism-1’, etc..

### Duplicate Names¶

If the name of an object specified in its constructor is the same as the name of an existing object of that type, its name is appended with a hyphenated integer suffix (<object name>-n) that is incremented for each additional duplicated name, beginning with ‘1’. The object with the original name (implicitly instance ‘0’) is left intact.

There is one exception to this rule, for the naming of Port. Ports of the same type, but that belong to different Mechanisms, can have the same name (for example, TransferMechanism-0 and TransferMechanism-1 can both have an InputPort named input_port-0 (the default name for the first InputPort); however, if a Port is assigned a name that is the same as another Port of that type belonging to the same Mechanism, it is treated as a duplicate, and its name is suffixed as described above.