6.19.4 Autoload

Macro: autoload file/module item ...

Sets up item ... to be autoloaded. That is, when an item is referenced for the first time, file/module is loaded before the item is evaluated. This delays the loading of file/module until it is needed.

You can specify either a string file name or a symbol module name to file/module. If it is a string, the named file is loaded. If it is a symbol, the named module is loaded (using the same rule as of use), then the binding of item in the file/module is imported to the module used the autoload (See section 4.11.2 Defining and selecting modules, for details of use).

Item can be either a variable name (symbol), or a form (:macro symbol). If it is a variable, the named file/module is loaded when the variable is about to be evaluated. If it is the latter form, the named file/module is loaded when a form (symbol arg ...) is about to be compiled, which enables autoloading macros.

file/module must define symbol in it, or an error is signalled when file/module is autoloaded.

The following is an example of autoloading procedures.

(autoload "foo" foo0 foo1) (autoload "bar" bar0 bar1) (define (foobar x) (if (list? x) (map bar0 x) (foo0))) (foobar '(1 2)) ; "bar" is loaded at this moment (foobar #f) ; "foo" is loaded at this moment

Note that if you set to autoload macro, the file/module is loaded immediately when such form that uses the macro is compiled, regardless of the piece of the code is executed or not.