From 2b3b5476f5f9eb4bfd2e4e03b14ad4670ae45b01 Mon Sep 17 00:00:00 2001
From: Ray John Alovera <rakista112@gmail.com>
Date: Fri, 30 Jul 2021 13:04:06 +0800
Subject: [PATCH 1/3] - add takeWhile function

---
 List.ark | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/List.ark b/List.ark
index 47204be..c442a8e 100644
--- a/List.ark
+++ b/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

From d940e299d086dfd3b1e1ac016015b63c931a3343 Mon Sep 17 00:00:00 2001
From: Ray John Alovera <rakista112@gmail.com>
Date: Fri, 30 Jul 2021 13:04:30 +0800
Subject: [PATCH 2/3] remove whitespace

---
 List.ark | 1 -
 1 file changed, 1 deletion(-)

diff --git a/List.ark b/List.ark
index c442a8e..b8f3850 100644
--- a/List.ark
+++ b/List.ark
@@ -259,7 +259,6 @@
 (let list:takeWhile (fun (_L _f) {
     (mut _index 0)
     (mut _output [])
-
     (mut continue true)
     (while continue 
         (if (_f (@ _L _index))

From 1e08fc9fc3a031c37d05b62962e065aa0133463d Mon Sep 17 00:00:00 2001
From: Ray John Alovera <rakista112@gmail.com>
Date: Fri, 30 Jul 2021 13:14:01 +0800
Subject: [PATCH 3/3] - fix infinite loop - add tests

---
 List.ark             | 2 +-
 tests/list-tests.ark | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/List.ark b/List.ark
index b8f3850..120fca1 100644
--- a/List.ark
+++ b/List.ark
@@ -260,7 +260,7 @@
     (mut _index 0)
     (mut _output [])
     (mut continue true)
-    (while continue 
+    (while (and (< _index (len _L)) continue)
         (if (_f (@ _L _index))
             {
                 (set _output (append _output (@ _L _index)))
diff --git a/tests/list-tests.ark b/tests/list-tests.ark
index f73fb59..863049c 100644
--- a/tests/list-tests.ark
+++ b/tests/list-tests.ark
@@ -51,6 +51,11 @@
     (set tests (assert-eq (list:take a 1) [1] "take" tests))
     (set tests (assert-eq (list:take a 100) a "take" tests))
 
+    (set tests (assert-eq (list:takeWhile a (fun (c) (< c 0))) [] "takeWhile" tests))
+    (set tests (assert-eq (list:takeWhile a (fun (c) (< c 2))) [1] "takeWhile" tests))
+    (set tests (assert-eq (list:takeWhile a (fun (c) (< c 3))) [1 2] "takeWhile" tests))
+    (set tests (assert-eq (list:takeWhile a (fun (c) (< c 5))) [1 2 3] "takeWhile" tests))
+
     (set tests (assert-eq (list:unzip zipped) [[1 2 3 4] [5 6 7 8]] "unzip" tests))
     (set tests (assert-eq (list:unzip []) [[] []] "unzip" tests))