https://github.com/rocktakey/recur
Tail call optimization for Emacs.
https://github.com/rocktakey/recur
Last synced: 3 months ago
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Tail call optimization for Emacs.
- Host: GitHub
- URL: https://github.com/rocktakey/recur
- Owner: ROCKTAKEY
- License: gpl-3.0
- Created: 2021-11-04T06:32:19.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2023-01-21T18:36:50.000Z (over 2 years ago)
- Last Synced: 2025-02-08T12:27:47.311Z (4 months ago)
- Language: Emacs Lisp
- Size: 35.2 KB
- Stars: 14
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.org
- Funding: .github/FUNDING.yml
- License: LICENSE
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* Tail call optimization for Emacs.
=recur= means recursive call (like clojure). All =recur= must be called on tail.
#+begin_src emacs-lisp
(recur-loop ;Same as `recur-let'
((x 5)
(y 1))
(if (eq x 0)
y
(recur (1- x) (* x y))))
;; => 120
(recur-progv '(x y) '(5 1)
(if (eq x 0)
y
(recur (1- x) (* x y))))
;; => 120
(recur-defun factorial (x &optional y)
(setq y (or y 1))
(if (eq x 0)
y
(recur (1- x) (* x y))))
;; => factorial
(factorial 5 1)
;; => 120
(factorial 5)
;; => 120
(recur-defun sum (init &rest list)
(if list
(recur (+ init (car list))
(cdr list))
init))
;; => sum
(sum 1 2 3 4 5)
;; 15
#+end_src
* How to Use?
** =recur-loop= / =recur-let=
Recursively callable =let=. Similar to =loop= in clojure.
This is same as =recur-progv=, except using =BINDINGS= like =let= instead of
=SYMBOLS= and =INITVALUES=. =BODY= is evaluated with variables set by =BINDINGS=.
Note that =recur= MUST be tail recursion and this macro optimize tail call.
** =recur-progv=
Recursively callable =cl-progv=.
=SYMBOLS=, =INITVALUES= (as =VALUES=), and =BODY= are same as arguments of =cl-progv=.
In addition, you can use function =recur= in =BODY= form. This function take
arguments same number as length of =SYMBOLS=, and evaluate =BODY= form with =SYMBOLS=
bounded by each value of arguments.
Note that =recur= MUST be tail recursion and this macro optimize tail call.
** =recur-defun=
Define function with tail call optimization.
=NAME=, =ARGLIST=, =DOCSTRING= and =BODY= is same as arguments of =defun=.
=recur= in =BODY= calls the function named NAME itself with arguments.
=recur= cannot recieve variable length arguments, so you must pass one list
even as =&rest= argument.
Note that =recur= MUST be tail recursion and this macro optimize tail call.
* License
This package is licensed by GPLv3. See [[file:LICENSE][LICENSE]].