Add generic sums example

2 files changed, 30 insertions, 0 deletions

diff --git a/examples/30-generic-sums/shed.toml b/examples/30-generic-sums/shed.toml
new file mode 100644
index 00000000..842e1e9c
--- /dev/null
+++ b/examples/30-generic-sums/shed.toml
@@ -0,0 +1,7 @@
+[[shed.bins]]
+name = "hello-world"
+main-namespace = "HelloWorld"
+
+[[shed.examples]]
+bin = "hello-world"
+expected-output = "Some(hello, world!)\nNone"
diff --git a/examples/30-generic-sums/src/HelloWorld.shed b/examples/30-generic-sums/src/HelloWorld.shed
new file mode 100644
index 00000000..314546b5
--- /dev/null
+++ b/examples/30-generic-sums/src/HelloWorld.shed
@@ -0,0 +1,23 @@
+struct Some[T](.value: T) {}
+
+struct None() {}
+
+sumtype Option[T] = Some[T] | None;
+
+pub fun main() ! Io -> Unit {
+    printOption!(Some[String](.value = "hello, world!"));
+    printOption!(None());
+}
+
+fun printOption(option: Option[String]) !Io -> Unit {
+    when (option) {
+        is Some[String] {
+            print!("Some(");
+            print!(option.value);
+            print!(")\n");
+        }
+        is None {
+            print!("None\n");
+        }
+    }
+}