From f8578936553468785ff1c70fb7f4b0efebfbf55d Mon Sep 17 00:00:00 2001
From: Jan Tuomi <jans.tuomi@gmail.com>
Date: Mon, 26 Sep 2022 16:29:32 +0300
Subject: Add maybe concept

---
 examples/algebraic-types-concept.lisp | 19 -------------------
 examples/maybe.lisp                   | 28 ++++++++++++++++++++++++++++
 2 files changed, 28 insertions(+), 19 deletions(-)
 delete mode 100644 examples/algebraic-types-concept.lisp
 create mode 100644 examples/maybe.lisp

diff --git a/examples/algebraic-types-concept.lisp b/examples/algebraic-types-concept.lisp
deleted file mode 100644
index 315a693..0000000
--- a/examples/algebraic-types-concept.lisp
+++ /dev/null
@@ -1,19 +0,0 @@
-(let just (\[a]
-    ["maybe" "just" a]))
-(let nothing (\[]
-    ["maybe" "nothing"]))
-
-(let at (\[n seq]
-    (match seq
-        [] (nothing)
-        (match n
-            0 (head seq)
-            (at (- n 1) (tail seq))))))
-
-(let from-just (at 2))
-(let kind (at 1))
-
-(let m (just 10))
-(match (kind m)
-    "just" (from-just m)
-    "nothing" "nothing")
diff --git a/examples/maybe.lisp b/examples/maybe.lisp
new file mode 100644
index 0000000..ce2cd03
--- /dev/null
+++ b/examples/maybe.lisp
@@ -0,0 +1,28 @@
+; LIB
+
+(let just (\[a]
+    ["maybe" "just" a]))
+(let nothing (\[]
+    ["maybe" "nothing"]))
+
+(let at (\[n seq]
+    (match seq
+        [] (nothing)
+        (match n
+            0 (head seq)
+            (at (- n 1) (tail seq))))))
+
+(let from-just (at 2))
+(let kind (at 1))
+
+(let map (\[f m]
+    (match (kind m)
+        "just" (just (f (from-just m)))
+        "nothing")))
+
+; TESTING
+
+(let m (just 10))
+(match (kind m)
+    "just" (from-just m)
+    "nothing" "nothing")
-- 
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