Lions & tigers & variables - Oh my! [was: Lisp error on function :documentation]

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

> global variables can be virtually eliminated by using closures

_*ALL*_ variables can (really, not virtually) be
eliminated, with combinatory logic.  Magic.

That doesn't mean you'll likely find it preferable
to do all your programming without variables.  It
does mean that variables aren't at all necessary.

Variables are human bookkeeping labels/tags, to
help our feeble memories cope.  Useful sometimes,
a huge PITA other times - think assembler, C, etc.,
where pretty much every bit of program requires a
variable.

__


Yes, all of that is OT.  What's not OT is that for
Emacs users, _in particular_, special (global) vars
can be quite useful.

Precisely _because_ they can let you reach across
existing code without modifying it, as far as you
like, and change behavior.  And still have some
control over extent etc.  Dynamic binding is yet
another story of power being usable for good & bad.
Be careful how you use it; know why you use it.

RMS summarized the use cases 42 years ago - still
100% relevant today:

https://www.gnu.org/software/emacs/emacs-paper.html#SEC15


___

SKI etc.:

https://en.wikipedia.org/wiki/Combinatory_logic

42:

https://en.wikipedia.org/wiki/The_Hitchhiker%27s_Guide_to_the_Galaxy#42,_or_The_Answer_to_the_Ultimate_Question_of_Life,_The_Universe,_and_Everything

https://en.wikipedia.org/wiki/Jackie_Robinson