LibraryModule Declaration and Attributes

LibraryModule declaration and attributes

LibraryModule nodes create a separate tree in the model tree along with a separate namespace for all identifier declarations in that subtree. The model contents associated with a LibraryModule is always stored in a separate source file. Contrary to Section and Module nodes, the name of this source file cannot be specified in the LibraryModule declaration. Rather, it is specified when you add the library to your project using the Library Manager, as discussed in Library projects and the library manager. The attributes of LibraryModule nodes are listed in the following table.

Attribute	Value-type	See also page
Prefix	identifier
Interface	identifier-list
Property	NoSave	The Property attribute
Required Units	quantity::unit-list
Comment	comment string	The Text and Comment attributes

Library modules and namespaces

Like a normal module, each LibraryModule is supplied with a separate namespace. Compared to normal modules, however, the visibility rules for identifiers in a library modules are different. They are more in line with the intended use of libraries, i.e. to enable a single developer to work independently on the model source of a library.

The Interface attribute

Through the Interface attribute of a LibraryModule you can specify the list of identifiers in the module that you want to be part of its public interface. Only identifiers in the library interface can be accessed in model declarations, pages and menu items that are not part of the library at hand. Library identifiers not in the interface are strictly private to the library, and can never be used outside of the library.

The Prefix attribute

With the mandatory Prefix attribute of a LibraryModule node, you must specify a module-specific prefix to be used in conjunction with the :: operator. The value of the Prefix attribute should be a unique name within the main model.

The Required Units attribute

It is recommended to declare all quantities and units at one place in the main model, and thus not declare quantities in a library as this could lead to a model where the same quantities and units are declared multiple times. With the Required Units attribute of a LibraryModule node, you can specify the units that are used in the library and thus should be present in the model that includes this library. If the required units are SI units, then they will be added automatically to the model that includes this library. The value of this attribute is a list of quantity::unit specifications. For example: SI_Time_Duration::hour, SI_Length::inch.

No propagation to global namespace

Even though identifiers in the interface of the library are visible outside of the library, AIMMS always requires the use of the library prefix to reference such identifiers. Library modules do not support the Public attribute of ordinary modules to propagate identifiers to the global namespace.

Library initialization and termination

When creating a new library, AIMMS will automatically add LibraryInitialization, PostLibraryInitialization, PreLibraryTermination and LibraryTermination procedures to it. These procedures will be executed during the initialization and termination of your model. The distinction between these steps are explained in more detail in Model Initialization and Termination.