Re: LISP Questions - random, random elements and memory management

[Kevin Rodgers]

Jeff Clough wrote:
> Lastly, I have a function that takes two lists, pulls a random element
> from each and concats the elements to form a string (a random name
> generator).  It works just swell with the lists as defconsts, but one
> of the lists is quite large (88,000 elements today) and burns about a
> megabyte of RAM.  It takes above half a second to evaluate the
> defconst, but then using the list is zippy (even nth'ing near the end
> of the list takes no time).
>
> What is the done thing in Emacs Lisp to keep this data out of memory
> until it's needed that also lets the function stay zippy?  Bonus
> points if I can keep the data and function bundled up in the same .el
> file.

The data *is* in memory.  The function is zippy because nth is fast, in
turn because cdr is fast (and implemented in C).  And perhaps the cons
cells for the list are allocated in adjacent memory, if it is
constructed all at once.

Of course you can put the data (defconst forms) and function (defun) in
the same .el file!

> I've taken a look at autoload, provide and require, but I'm not
> certain I understand them fully or how they would be used to solve
> this problem.

Me neither.

--
Kevin Rodgers
Denver, Colorado, USA