Stefan Monnier <monnier@iro.umontreal.ca> writes:

> "Real" functional programming tends to use lots of small functions, so
> it's important to optimize the implementation of function calls and
> closure creations.  Elisp is not great at either of those:

I meant that Elisp (like most Lisps) is a good fit for functional
programming from the point of view of the semantics of the language and
the constructs it provides.

> The Elisp style is evolving and those inefficiencies are more often
> visible (e.g. cl-print's main bottleneck is the cost of apply+&rest in
> my tests), so we can hope that someone will work on reducing them at
> some point;

That'd be nice indeed, but one beautiful day we'll get Guile's VM
anyway!

> and in general I do recommend to make your code clean and
> correct first and foremost.  But keep in mind that Elisp's support for
> functional programming is a bit lacking in efficiency.

I've not yet hit any performance issue regarding fun calls or heavy use
of closures :)

Cheers,
Nico