From 5d76fa1b86ff1bd15b9c6b546916bc03c9d9b9b4 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sat, 2 May 2026 09:33:20 +0100
Subject: Add example for sum types

---
 examples/02-sum/hobgoblin.json5                    |  1 +
 examples/02-sum/output/java/.gitignore             |  2 ++
 examples/02-sum/output/java/pom.xml                | 39 ++++++++++++++++++++++
 .../src/main/java/org/zwobble/example/Main.java    | 22 ++++++++++++
 examples/02-sum/src/shapes.hob                     | 14 ++++++++
 5 files changed, 78 insertions(+)
 create mode 100644 examples/02-sum/hobgoblin.json5
 create mode 100644 examples/02-sum/output/java/.gitignore
 create mode 100644 examples/02-sum/output/java/pom.xml
 create mode 100644 examples/02-sum/output/java/src/main/java/org/zwobble/example/Main.java
 create mode 100644 examples/02-sum/src/shapes.hob

(limited to 'examples/02-sum')

diff --git a/examples/02-sum/hobgoblin.json5 b/examples/02-sum/hobgoblin.json5
new file mode 100644
index 0000000..0967ef4
--- /dev/null
+++ b/examples/02-sum/hobgoblin.json5
@@ -0,0 +1 @@
+{}
diff --git a/examples/02-sum/output/java/.gitignore b/examples/02-sum/output/java/.gitignore
new file mode 100644
index 0000000..ff511d4
--- /dev/null
+++ b/examples/02-sum/output/java/.gitignore
@@ -0,0 +1,2 @@
+/src/gen/
+/target/
diff --git a/examples/02-sum/output/java/pom.xml b/examples/02-sum/output/java/pom.xml
new file mode 100644
index 0000000..7493667
--- /dev/null
+++ b/examples/02-sum/output/java/pom.xml
@@ -0,0 +1,39 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>org.zwobble.hobgoblin.examples</groupId>
+  <artifactId>example</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>25</maven.compiler.source>
+    <maven.compiler.target>25</maven.compiler.target>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>build-helper-maven-plugin</artifactId>
+        <version>3.6.1</version>
+        <executions>
+          <execution>
+            <id>add-source</id>
+            <phase>generate-sources</phase>
+            <goals>
+              <goal>add-source</goal>
+            </goals>
+            <configuration>
+              <sources>
+                <source>src/gen/java</source>
+              </sources>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>
diff --git a/examples/02-sum/output/java/src/main/java/org/zwobble/example/Main.java b/examples/02-sum/output/java/src/main/java/org/zwobble/example/Main.java
new file mode 100644
index 0000000..41522e6
--- /dev/null
+++ b/examples/02-sum/output/java/src/main/java/org/zwobble/example/Main.java
@@ -0,0 +1,22 @@
+package org.zwobble.example;
+
+import org.zwobble.example.types.shapes.Shape;
+import org.zwobble.example.types.shapes.Rectangle;
+import org.zwobble.example.types.shapes.Triangle;
+
+public class Main {
+    public static void main() {
+        Shape shape = createShape();
+        var area = switch (shape) {
+            case Rectangle(var width, var height) ->
+                width * height;
+
+            case Triangle(var width, var height) ->
+                width * height / 2;
+        };
+    }
+
+    private static Shape createShape() {
+        return new Rectangle(10, 25);
+    }
+}
diff --git a/examples/02-sum/src/shapes.hob b/examples/02-sum/src/shapes.hob
new file mode 100644
index 0000000..08336c5
--- /dev/null
+++ b/examples/02-sum/src/shapes.hob
@@ -0,0 +1,14 @@
+sum Shape {
+    variant Rectangle;
+    variant Triangle;
+}
+
+struct Rectangle {
+    field width: Int32;
+    field height: Int32;
+}
+
+struct Triangle {
+    field width: Int32;
+    field height: Int32;
+}
-- 
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