Document opaque types

Closes https://github.com/gleam-lang/language-tour/issues/63

1 files changed, 15 insertions, 0 deletions

diff --git a/src/content/chapter5_advanced_features/lesson04_panic/code.gleam b/src/content/chapter5_advanced_features/lesson04_panic/code.gleam
new file mode 100644
index 0000000..fce9d66
--- /dev/null
+++ b/src/content/chapter5_advanced_features/lesson04_panic/code.gleam
@@ -0,0 +1,15 @@
+import gleam/io
+
+pub fn main() {
+  print_score(10)
+  print_score(100_000)
+  print_score(-1)
+}
+
+pub fn print_score(score: Int) {
+  case score {
+    score if score > 1000 -> io.println("High score!")
+    score if score > 0 -> io.println("Still working on it")
+    _ -> panic as "Scores should never be negative!"
+  }
+}