add drop procedure

LIPS-scheme · Mar 24, 2024 · 226e659 · 226e659
1 parent 1fcb441
commit 226e659
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -32,6 +32,7 @@
 * add `zip` procedure (inspired by [Lodash](https://docs-lodash.com/v4/zip/))
 * add `with-input-from-string` and `read-all` [#327](https://github.com/jcubic/lips/issues/327)
 * add `#!fold-case` and `#!no-fold-case` directives [#342](https://github.com/jcubic/lips/issues/342)
+* add `drop` procedure
 ### Bugfix
 * fix `let-values` to allow binding to list [#281](https://github.com/jcubic/lips/issues/281)
 * fix wrong strings in `string-fill!`
@@ -72,7 +73,7 @@
 * fix escape ellipsis in syntax-rules [#334](https://github.com/jcubic/lips/issues/334)
 * fix parsing inexact complex without real part and `inexact->exact` procedure [#340](https://github.com/jcubic/lips/issues/340)
 * fix `equal?` on cycles [#302](https://github.com/jcubic/lips/issues/302)
-* fix Petrifsky let [#341](https://github.com/jcubic/lips/issues/341)
+* fix Petrofsky let [#341](https://github.com/jcubic/lips/issues/341)
 
 ## 1.0.0-beta.18
 ### Breaking

diff --git a/dist/std.min.scm b/dist/std.min.scm
diff --git a/dist/std.scm b/dist/std.scm
diff --git a/dist/std.xcb b/dist/std.xcb
diff --git a/lib/bootstrap.scm b/lib/bootstrap.scm
@@ -861,6 +861,16 @@
         (reverse result)
         (loop (cons (car lst) result) (- i 1) (cdr lst)))))
 
+;; -----------------------------------------------------------------------------
+(define (drop lst n)
+  "(take list n)
+
+   Returns a list where first n elements are removed."
+  (let loop ((i n) (lst lst))
+    (if (or (null? lst) (<= i 0))
+        lst
+        (loop (- i 1) (cdr lst)))))
+
 ;; -----------------------------------------------------------------------------
 (define (zip . lists)
   "(zip list1 list2 ...)