branch: externals/dash
commit b540ebb9d6289a54188649818ffbab9bf4e859d6
Author: Per Weijnitz <per.weijn...@gmail.com>
Commit: Basil L. Contovounesios <conto...@tcd.ie>
Refactor -partition-after-pred to avoid recursion
* dash.el (--partition-after-pred): New anaphoric macro.
(-partition-after-pred): Use it.
* dev/examples.el (-partition-after-pred): Test it.
---
dash.el | 33 +++++++++++++++++++++------------
dev/examples.el | 4 +++-
2 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/dash.el b/dash.el
index c483a00..69c474b 100644
--- a/dash.el
+++ b/dash.el
@@ -1382,20 +1382,29 @@ returns the header value, but only after seeing at
least one
other value (the body)."
(--partition-by-header (funcall fn it) list))
+(defmacro --partition-after-pred (form list)
+ "Anaphoric form of `-partition-after-pred'."
+ (let ((r (make-symbol "result"))
+ (s (make-symbol "sublist"))
+ (l (make-symbol "list")))
+ `(let ((,l ,list))
+ (when ,l
+ (let* ((,r nil)
+ (,s nil))
+ (while ,l
+ (let* ((it (car ,l)))
+ (!cdr ,l)
+ (!cons it ,s)
+ (when ,form
+ (!cons (nreverse ,s) ,r)
+ (setq ,s nil))))
+ (if ,s
+ (!cons (nreverse ,s) ,r))
+ (nreverse ,r))))))
+
(defun -partition-after-pred (pred list)
"Partition directly after each time PRED is true on an element of LIST."
- (when list
- (let ((rest (-partition-after-pred pred
- (cdr list))))
- (if (funcall pred (car list))
- ;;split after (car list)
- (cons (list (car list))
- rest)
-
- ;;don't split after (car list)
- (cons (cons (car list)
- (car rest))
- (cdr rest))))))
+ (--partition-after-pred (funcall pred it) list))
(defun -partition-before-pred (pred list)
"Partition directly before each time PRED is true on an element of LIST."
diff --git a/dev/examples.el b/dev/examples.el
index 4382ba4..81d6da9 100644
--- a/dev/examples.el
+++ b/dev/examples.el
@@ -806,7 +806,9 @@ value rather than consuming a list to produce a single
value."
(-partition-after-pred #'booleanp '(t t)) => '((t) (t))
(-partition-after-pred #'booleanp '(0 0 t t 0 t)) => '((0 0 t) (t) (0 t))
(-partition-after-pred #'booleanp '(t)) => '((t))
- (-partition-after-pred #'booleanp '(0 t)) => '((0 t)))
+ (-partition-after-pred #'booleanp '(0 t)) => '((0 t))
+ (--partition-after-pred (= 1 (% it 2)) '(0 0 0 1 0 1 1 0 1))
+ => '((0 0 0 1) (0 1) (1) (0 1)))
(defexamples -partition-before-pred
(-partition-before-pred #'booleanp '()) => '()
