branch: externals/dash
commit 9065e1bdaa990b38ab22cb32b9b8132e58c71612
Author: Matus Goljer <[email protected]>
Commit: Matus Goljer <[email protected]>
[-let] Final cdr shift optimization
---
dash.el | 16 ++++++++++++----
dev/examples.el | 8 +++++++-
2 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/dash.el b/dash.el
index 7e7db7e..a66d3cb 100644
--- a/dash.el
+++ b/dash.el
@@ -1198,11 +1198,19 @@ SOURCE is a proper or improper list."
;; because each bind-body has a side-effect of chopping the head
;; of the list, we must create a binding even for _ places
((symbolp (car match-form))
- (cons (list (car match-form) `(prog1 (car ,s) (!cdr ,s)))
- (dash--match-cons-1 (cdr match-form) s)))
+ (cond
+ ((cdr match-form)
+ (cons (list (car match-form) `(prog1 (car ,s) (!cdr ,s)))
+ (dash--match-cons-1 (cdr match-form) s)))
+ (t
+ (list (list (car match-form) `(car ,s))))))
(t
- (-concat (dash--match (car match-form) `(prog1 (car ,s) (!cdr ,s)))
- (dash--match-cons-1 (cdr match-form) s)))))
+ (cond
+ ((cdr match-form)
+ (-concat (dash--match (car match-form) `(prog1 (car ,s) (!cdr ,s)))
+ (dash--match-cons-1 (cdr match-form) s)))
+ (t
+ (dash--match (car match-form) `(car ,s)))))))
((eq match-form nil)
nil)
(t
diff --git a/dev/examples.el b/dev/examples.el
index aa171f4..ae4c643 100644
--- a/dev/examples.el
+++ b/dev/examples.el
@@ -740,7 +740,13 @@ new list."
(list a b c d)
(error "previous call should fail.")))
(error t)) => t
- (-let [(a . (b . c)) (cons 1 (cons 2 3))] (list a b c)) => '(1 2 3))
+ (-let [(a . (b . c)) (cons 1 (cons 2 3))] (list a b c)) => '(1 2 3)
+ ;; final cdr optimization
+ (-let [(((a))) (list (list (list 1 2) 3) 4)] a) => 1
+ (-let [(((a b) c) d) (list (list (list 1 2) 3) 4)] (list a b c d)) => '(1
2 3 4)
+ (-let [(((a b) . c) . d) (list (list (list 1 2) 3) 4)] (list a b c d)) =>
'(1 2 (3) (4))
+ (-let [(((a b) c)) (list (list (list 1 2) 3) 4)] (list a b c)) => '(1 2 3)
+ (-let [(((a b) . c)) (list (list (list 1 2) 3) 4)] (list a b c)) => '(1 2
(3)))
(defexamples -let*
(-let* (((a . b) (cons 1 2))
