skeeto / emacs-memoize Goto Github PK

Elisp memoization functions

License: The Unlicense

Emacs Lisp 96.61% Makefile 3.39%

emacs-memoize's Introduction

Elisp memoization functions

See the header in the source file for details. It's very easy to use:

(require 'memoize)

(memoize 'my-function)

The macro defmemoize is also provided to directly create memoized functions:

(defmemoize my-expensive-function (n)
  (if (zerop n)
      1
    (* n (my-expensive-function (1- n)))))

Some functions are run over buffer contents, and need to be cached only so long as the buffer contents do not change. For these use-cases, we have the function memoize-by-buffer-contents as well as the defmemoize-by-buffer-contents macro.

To restore the original definition of a memoized function symbol (not a lambda or closure), use memoize-restore:

(memoize 'my-function)
(memoize-restore 'my-function)

emacs-memoize's People

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emacsmirror rolpereira ahyatt marik332000 npostavs alphapapa ktp-forked-repos zbelial salewski anticomputer cireu damiencassou djr7c4 kd-collective nagy jinnovation

emacs-memoize's Issues

Persistent memoization

Is there a way to have Emacs persist the cache between sessions, by saving and restoring the cache to the filesystem?

Throttle?

Hi again Chris,

I was browsing the CL Serapeum library and came across its throttle function. It seems complementary to memoize. I have a function in my Emacs config that I would like to throttle (it plays a notification sound when I get messages in matrix-client; I add it as advice to the built-in notification function), and it seems like this would be a good way to do it. What do you think?

(defun throttle (func interval)
  "Throttle FUNC: a closure, lambda, or symbol.

If argument is a symbol then install the throttled function over
the original function.  INTERVAL, a number of seconds or a
duration string as used by `timer-duration', determines how much
time must pass before FUNC will be allowed to run again."
  (cl-typecase func
    (symbol
     (when (get func :throttle-original-function)
       (user-error "%s is already throttled" func))
     (put func :throttle-original-documentation (documentation func))
     (put func 'function-documentation
          (concat (documentation func) " (throttled)"))
     (put func :throttle-original-function (symbol-function func))
     (fset func (throttle--wrap (symbol-function func) interval))
     func)
    (function (throttle--wrap func interval))))

(defun throttle--wrap (func interval)
  "Return the throttled version of FUNC.
INTERVAL, a number of seconds or a duration string as used by
`timer-duration', determines how much time must pass before FUNC
will be allowed to run again."
  (let ((interval (cl-typecase interval
                    ;; Convert interval to seconds
                    (float interval)
                    (integer interval)
                    (string (timer-duration interval))
                    (t (user-error "Invalid interval: %s" interval))))
        last-run-time)
    (lambda (&rest args)
      (when (or (null last-run-time)
                (>= (float-time (time-subtract (current-time) last-run-time))
                    interval))
        (setq last-run-time (current-time))
        (apply func args)))))

Optional keywords (e.g. `timeout`) for the `defmemoize` macro

May I suggest to add the following boilerplate to the defmemoize macro:

(defmacro defmemoize (name arglist &rest body)
  "Create a memoize'd function.
NAME, ARGLIST, DOCSTRING and BODY have the same meaning as in `defun'."
  (declare (indent 2) (doc-string 3) (debug defun))
  (let (doc-form doc-string keyword-plist)
    (when (> (length body) 1)
      (if (eq (car-safe (car-safe body)) 'format)
          (setq doc-form (pop body))
        (when (stringp (car-safe body))
          (setq doc-string (pop body)))))
    (while (keywordp (car-safe body))
      (setq keyword-plist (plist-put keyword-plist (pop body) (pop body))))
    (when (and body (consp (car body)) (eq (caar body) 'interactive))
      (user-error "Memoizing interactive function (`%s') is discouraged" name))
    `(progn
       (defun ,name ,arglist
         ,@(when doc-string `(,doc-string))
         ,@body)
       ,(when doc-form
          `(put (quote ,name) 'function-documentation ,doc-form))
       (memoize (quote ,name) (plist-get keyword-plist :timeout)))))

Documentation string and form parsing and handling;
Optional keywords (e.g. timeout) parsing and handling;
Error upon attempt to memoize an interactive function at compile time (maybe worth moving that piece to memoize function itself, so I leave this one up to you).

Mainly, one could now do:

(defmemoize foo (bar &optional baz)
  "..."
  :timeout "7 hours"
  ...)

Thanks and cheers!

`defmemoize` has wrong `indent` for argument list

Try to wrap argument list to the next line like this

(defmemoize foo
  (&optional xxx)
  "..."
  ...)

and you will see that, after indentation, instead of 4 spaces, the argument list is only indented by 2.

Typo in defmemoize example

You used x in the arglist but then n in the body.
https://github.com/skeeto/emacs-memoize/blob/master/memoize.el#L21-L24

buffer-hash function in Emacs 26

Hi Chris,

Just a reminder that Emacs 26 has a new buffer-hash function, which seems like could be useful in this package.

tagged release

Is it possible to get a 1.0.1 tag? That way this could appear in MELPA Stable. Thanks!

De-memoize function?

Hi Chris,

What do you think about adding a function to de-memoize memoized functions? I'm thinking about using memoize with magit-todos to cache a magit function call, but I'd like to only do that when the minor mode is activated, and then de-memoize it when the mode is deactivated, so as not to permanently interfere with magit.

Redefining a function created with defmemoize disables memoization

For example, with the function

(defmemoize f (x)
  (sit-for 1)
  (* x x))

(f 3)
(f 3)

The first call (f 3) takes 1 second and the next one is instant as expected. However, if one evaluates the code above and then evaluates it again a second time, both (f 3) calls take one second. This shows that memoization is not working after f has been redefined. This is easy to fix and I will submit a pull request in a moment.

skeeto / emacs-memoize Goto Github PK

emacs-memoize's Introduction

Elisp memoization functions

emacs-memoize's People

Contributors

Stargazers

Watchers

Forkers

emacs-memoize's Issues

Persistent memoization

Throttle?

Optional keywords (e.g. `timeout`) for the `defmemoize` macro

`defmemoize` has wrong `indent` for argument list

Typo in defmemoize example

buffer-hash function in Emacs 26

tagged release

De-memoize function?

Redefining a function created with defmemoize disables memoization

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