Added contains functions in List and Option. Fixed one type error catch

2020-08-26 11:56:18 +02:00
parent ed5447e430
commit 7e32ef57c2
4 changed files with 32 additions and 7 deletions
@@ -15,10 +15,14 @@ namespace List =
    _::t => Some(t)

  function last(l : list('a)) : option('a) = switch(l)
-    []  => None
-    [x] => Some(x)
+    []   => None
+    [x]  => Some(x)
    _::t => last(t)

+  function contains(e : 'a, l : list('a)) = switch(l)
+    []   => false
+    h::t => h == e || contains(e, t)
+
 /** Finds first element of `l` fulfilling predicate `p` as `Some` or `None`
 * if no such element exists.
 */