A special case of extensions is one that consists only of a single source file and which doesn't provide any additional syntax definitions. In this case, we can build and install the extensions simply by entering:
% csi -setup foo
where foo.scm is the name of the source file containing the code.
It should be noted that the extension-mechanism does not address any namespace-issues. It is recommended to use the export declaration- specifier to export toplevel names that are to be used by client code. This will hide module-local definitions. Prefixing exported names with something like <extension-name>:<definition> avoids namespace-collisions with other libraries and names of client code.