- add takeWhile function

Author: Ray Alovera

List.ark

@@ -245,6 +245,34 @@
     _output
 }))
 
+###
+# @meta List
+# @brief Take the first n elements of
+# @param _L the list to work on
+# @param _f the predicate
+# @details The original list is left unmodified.
+# =begin
+# (print (takeWhile [1 2 3 4 5 6 7 8 9 10] (fun (a) (< a 4))))  # [1 2 3]
+# =end
+# @author https://github.com/rakista112
+##
+(let list:takeWhile (fun (_L _f) {
+    (mut _index 0)
+    (mut _output [])
+
+    (mut continue true)
+    (while continue 
+        (if (_f (@ _L _index))
+            {
+                (set _output (append _output (@ _L _index)))
+                (set _index (+ 1 _index))
+            }
+            (set continue false)
+        )
+    )
+    _output
+}))
+
 ###
 # @brief Unzip a list of [[a b] [c d]...] into [[a c ...] [b d ...]]
 # @param _L the list to work on