ASDF-System-Connections provides auto-loading of systems that only make sense when several other systems are loaded. If I'm lucky, an example will make this clear!
CL-Containers and CL-Variates are separate systems and can therefore be loaded independently. If both of them are loaded, however, then it makes sense to also load code that uses CL-Variates to sample random elements from containers. Rather than requiring you to remember to load that extra system (and to load it only after both Cl-Containers and CL-Variates are loaded), ASDF-System-Connections lets you set things up so that loading happens automatically.
Here is a simple example from metabang-bind's system definition:
(asdf:defsystem-connection bind-and-metatilities
:requires (metabang-bind metatilities-base)
:perform (load-op :after (op c)
(use-package (find-package :metabang-bind)
(find-package :metatilities))))The requires clause specifies the other systems that must be loaded before this connection will be activated. The rest of the system definition is regular ASDF. ASDF-System-connections will be loaded as soon as the systems they require are all loaded and they will only be loaded once. Before loading a system that uses a system connection, you should load ASDF-System-Connections in the usual manner:
(asdf:oos 'asdf:load-op 'asdf-system-connections)
Nope. Sorry, there isn't one. You can, however, contact Gary King. The best way to keep updated is to follow the metabang weblog: unClog
A Darcs repository is available. The command to get it is below:
ASDF-System-Connections should also be ASDF installable (and here is my GPG Key). There's also a handy gzipped tar file.
