branch: elpa/llama
commit fecd651d88f15a2503630ea38ae491bfcd132279
Author: Jonas Bernoulli <jo...@bernoul.li>
Commit: Jonas Bernoulli <jo...@bernoul.li>
Add llama--{left,right}-apply-partially a.k.a. partial / rpartial
---
.dir-locals.el | 9 ++++++++-
llama.el | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+), 1 deletion(-)
diff --git a/.dir-locals.el b/.dir-locals.el
index 3a491ef96b..6ecdd91bf1 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -1,2 +1,9 @@
((emacs-lisp-mode
- (indent-tabs-mode . nil)))
+ (indent-tabs-mode . nil)
+ ;; Instead of at the bottom of each library, you can also configure
+ ;; the shorthands in this file. Note that Melpa by default does not
+ ;; include it in packages, so you will have to explicitly add it to
+ ;; `:files' in the Melpa recipe. See `forge's recipe for an example.
+ (read-symbol-shorthands
+ ("partial" . "llama--left-apply-partially")
+ ("rpartial" . "llama--right-apply-partially"))))
diff --git a/llama.el b/llama.el
index 3b8eb553a7..eeb00728ad 100644
--- a/llama.el
+++ b/llama.el
@@ -500,6 +500,62 @@ expansion, and the looks of this face should hint at
that.")
(define-globalized-minor-mode global-llama-fontify-mode
llama-fontify-mode llama--turn-on-fontify-mode)
+;;; Partial applications
+
+(defun llama--left-apply-partially (fn &rest args)
+ "Return a function that is a partial application of FN to ARGS.
+
+ARGS is a list of the first N arguments to pass to FN. The result
+is a new function which does the same as FN, except that the first N
+arguments are fixed at the values with which this function was called.
+
+See also `llama--right-apply-partially', which instead fixes the last
+N arguments.
+
+These functions are intended to be used using the names `partial' and
+`rpartial'. To be able to use these shorthands in a file, you must set
+the file-local value of `read-symbols-shorthands', which was added in
+Emacs 28.1. For an example see the end of file \"llama.el\".
+
+This is an alternative to `apply-partially', whose name is too long."
+ (declare (pure t) (side-effect-free error-free))
+ (lambda (&rest args2)
+ (apply fn (append args args2))))
+
+(defun llama--right-apply-partially (fn &rest args)
+ "Return a function that is a right partial application of FN to ARGS.
+
+ARGS is a list of the last N arguments to pass to FN. The result
+is a new function which does the same as FN, except that the last N
+arguments are fixed at the values with which this function was called.
+
+See also `llama--left-apply-partially', which instead fixes the first
+N arguments.
+
+These functions are intended to be used using the names `rpartial' and
+`partial'. To be able to use these shorthands in a file, you must set
+the file-local value of `read-symbols-shorthands', which was added in
+Emacs 28.1. For an example see the end of file \"llama.el\"."
+ (declare (pure t) (side-effect-free error-free))
+ (lambda (&rest args2)
+ (apply fn (append args2 args))))
+
+;; An example of how one would use these functions:
+;;
+;; (list (funcall (partial (lambda (a b) (list a b)) 'fixed) 'after)
+;; (funcall (rpartial (lambda (a b) (list a b)) 'fixed) 'before))
+
+;; An example of the configuration that is necessary to enable this:
+;;
+;; Local Variables:
+;; read-symbol-shorthands: (
+;; ("partial" . "llama--left-apply-partially")
+;; ("rpartial" . "llama--right-apply-partially"))
+;; End:
+;;
+;; Alternatively you can set this variable in a ".dir-locals.el" file.
+;; See this package's ".dir-locals.el" for an example.
+
(provide 'llama)
;;; llama.el ends here
