RE: [External] : Re: ;;;###autoload declarations

[Drew Adams <drew.adams@oracle.com>]

> (info "(elisp) Autoload")
> 
> However, what I can see it fails to address why this is at all
> desirable to do and, assuming it is, in what cases more
> precisely it is useful.

If you never use anything from some library
then it isn't loaded.  That's the idea: load
code only if and when you need it.

Autoloaded commands (typically) and other
things (not so typically) are available to
the Help system, so you can see what they
do etc., even though their definitions
haven't been loaded.

If/when you invoke an autoloaded command,
_then_ the file defining it is loaded
(which often defines other commands etc.).
___

Another example of late binding - one of the
most important software ideas and practices.

Lazy evaluation (think purely functional
languages) is a prime example of late binding.
___

Beyond normal-order (i.e., outermost-first)
evaluation, which is used for lazy languages,
there's a more stringent on-need evaluation,
which is defined for some rewrite systems.
It needs costly analysis of code to determine
exactly what really needs to be evaluated when.