doc: added exercises 3 and 4

2 files changed, 27 insertions, 0 deletions

diff --git a/TUTORIAL.md b/TUTORIAL.md
index e0017d6..30e7d62 100644
--- a/TUTORIAL.md
+++ b/TUTORIAL.md
@@ -466,3 +466,29 @@ n saved
 > (fibonacci n)
 34 : Int
 ```
+
+
+Exercise 3: Generic functions – the identity
+--------------------------------------------
+
+Write the identity function for any type.
+
+This should make you familiar with typing function
+definitions that contain generics.
+
+
+Exercise 4: Map left / right (integers)
+---------------------------------------
+
+Write functions `map-left` and `map-right` that take a
+coproduct and a function and map the corresponding side of
+the given coproduct using the given function.
+
+Note: the solution is not in the same directory as the rest,
+but you can find implementations for these in the standard
+library.
+
+This exercise will train your abilities to use generics more
+than the last one. You will get familiar with coproducts.
+
+
diff --git a/solutions/id.slip b/solutions/id.slip
new file mode 100644
index 0000000..e0d768e
--- /dev/null
+++ b/solutions/id.slip
@@ -0,0 +1 @@
+(let id (fn x T T x))