review suggestions

config.json

@@ -1842,7 +1842,6 @@
           "results"
         ],
         "prerequisites": [
-          "custom-types",
           "recursion"
         ],
         "difficulty": 9

exercises/practice/zebra-puzzle/.meta/example.gleam

@@ -1,7 +1,18 @@
 import gleam/dict.{type Dict}
 import gleam/list
+import gleam/result
 
-pub type Solution {
+pub fn water_drinker() -> Result(String, Nil) {
+  solve()
+  |> result.map(fn(solution) { solution.water_drinker })
+}
+
+pub fn zebra_owner() -> Result(String, Nil) {
+  solve()
+  |> result.map(fn(solution) { solution.zebra_owner })
+}
+
+type Solution {
   Solution(water_drinker: String, zebra_owner: String)
 }
 
@@ -11,7 +22,7 @@ type Parameters =
 type Nationalities =
   Dict(Int, String)
 
-pub fn solve() -> Result(Solution, Nil) {
+fn solve() -> Result(Solution, Nil) {
   solve_for_colour(
     houses()
       |> list.permutations(),

exercises/practice/zebra-puzzle/src/zebra_puzzle.gleam

@@ -1,7 +1,7 @@
-pub type Solution {
-  Solution(water_drinker: String, zebra_owner: String)
+pub fn water_drinker() -> Result(String, Nil) {
+  todo
 }
 
-pub fn solve() -> Result(Solution, Nil) {
+pub fn zebra_owner() -> Result(String, Nil) {
   todo
 }

exercises/practice/zebra-puzzle/test/zebra_puzzle_test.gleam

@@ -6,12 +6,12 @@ pub fn main() {
   test_runner.main()
 }
 
-pub fn puzzle_test() {
-  let assert Ok(solution) = zebra_puzzle.solve()
-
-  solution.water_drinker
-  |> should.equal("Norwegian")
+pub fn drinks_water_test() {
+  zebra_puzzle.water_drinker()
+  |> should.equal(Ok("Norwegian"))
+}
 
-  solution.zebra_owner
-  |> should.equal("Japanese")
+pub fn owns_zebra_test() {
+  zebra_puzzle.zebra_owner()
+  |> should.equal(Ok("Japanese"))
 }