branch: externals/dash
commit f257fb907ecea0ca79df7c8599cfb5df0c30dff9
Author: Magnar Sveen <[email protected]>
Commit: Magnar Sveen <[email protected]>
Add -butlast
---
README.md | 11 +++++++++++
dash.el | 9 +++++++++
dev/examples.el | 6 ++++++
3 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/README.md b/README.md
index 5f0f46a..e8f7390 100644
--- a/README.md
+++ b/README.md
@@ -181,6 +181,7 @@ Other list functions not fit to be classified elsewhere.
* [-last](#-last-pred-list) `(pred list)`
* [-first-item](#-first-item-list) `(list)`
* [-last-item](#-last-item-list) `(list)`
+* [-butlast](#-butlast-list) `(list)`
* [-sort](#-sort-comparator-list) `(comparator list)`
* [-list](#-list-rest-args) `(&rest args)`
@@ -1410,6 +1411,16 @@ Return the last item of `list`, or nil on an empty list.
(-last-item nil) ;; => nil
```
+#### -butlast `(list)`
+
+Return a list of all items in list except for the last.
+
+```cl
+(-butlast '(1 2 3)) ;; => '(1 2)
+(-butlast '(1 2)) ;; => '(1)
+(-butlast '(1)) ;; => nil
+```
+
#### -sort `(comparator list)`
Sort `list`, stably, comparing elements using `comparator`.
diff --git a/dash.el b/dash.el
index 22f977b..8928009 100644
--- a/dash.el
+++ b/dash.el
@@ -399,6 +399,14 @@ Alias: `-find'"
"Return the last item of LIST, or nil on an empty list."
(car (last list)))
+(defun -butlast (list)
+ "Return a list of all items in list except for the last."
+ (let (result)
+ (while (cdr list)
+ (!cons (car list) result)
+ (!cdr list))
+ (nreverse result)))
+
(defmacro --count (pred list)
"Anaphoric form of `-count'."
(declare (debug (form form)))
@@ -1561,6 +1569,7 @@ structure such as plist or alist."
"--last"
"-first-item"
"-last-item"
+ "-butlast"
"-count"
"--count"
"-any?"
diff --git a/dev/examples.el b/dev/examples.el
index 945cfac..26ed0e4 100644
--- a/dev/examples.el
+++ b/dev/examples.el
@@ -549,6 +549,12 @@ new list."
(-last-item '(1 2 3)) => 3
(-last-item nil) => nil)
+ (defexamples -butlast
+ (-butlast '(1 2 3)) => '(1 2)
+ (-butlast '(1 2)) => '(1)
+ (-butlast '(1)) => nil
+ (-butlast nil) => nil)
+
(defexamples -sort
(-sort '< '(3 1 2)) => '(1 2 3)
(-sort '> '(3 1 2)) => '(3 2 1)
