From b7e7ebf6380dcf0c7f02fca9002318d36ffc5b96 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 12 Jun 2026 17:01:17 +0100
Subject: Add Java expression statement

---
 .../zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java  | 9 +++++++++
 .../compiler/output/lang/java/ast/JavaBlockStatement.java        | 2 +-
 .../compiler/output/lang/java/ast/JavaExpressionStatement.java   | 4 ++++
 .../hobgoblin/compiler/output/lang/java/JavaWriterTests.java     | 9 +++++++++
 4 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100644 src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaExpressionStatement.java

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
index aec83da..a7a3775 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriter.java
@@ -75,6 +75,10 @@ public class JavaWriter implements AutoCloseable {
 
     void writeBlockStatement(JavaBlockStatement statement) throws IOException {
         switch (statement) {
+            case JavaExpressionStatement expressionStatement -> {
+                writeExpressionStatement(expressionStatement);
+            }
+
             case JavaReturn returnStatement -> {
                 writeReturnStatement(returnStatement);
             }
@@ -203,6 +207,11 @@ public class JavaWriter implements AutoCloseable {
         }
     }
 
+    private void writeExpressionStatement(JavaExpressionStatement expressionStatement) throws IOException {
+        writeExpression(expressionStatement.expression());
+        this.writer.write(";");
+    }
+
     private void writeImplements(List<JavaTypeRef> implementsTypes) throws IOException {
         if (!implementsTypes.isEmpty()) {
             this.writer.write("implements ");
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBlockStatement.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBlockStatement.java
index 1ee5511..fe3e69a 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBlockStatement.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaBlockStatement.java
@@ -1,4 +1,4 @@
 package org.zwobble.hobgoblin.compiler.output.lang.java.ast;
 
-public sealed interface JavaBlockStatement permits JavaReturn {
+public sealed interface JavaBlockStatement permits JavaExpressionStatement, JavaReturn {
 }
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaExpressionStatement.java b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaExpressionStatement.java
new file mode 100644
index 0000000..2ec771f
--- /dev/null
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/output/lang/java/ast/JavaExpressionStatement.java
@@ -0,0 +1,4 @@
+package org.zwobble.hobgoblin.compiler.output.lang.java.ast;
+
+public record JavaExpressionStatement(JavaExpression expression) implements JavaBlockStatement {
+}
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
index 8ad22f9..8966d5e 100644
--- a/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/output/lang/java/JavaWriterTests.java
@@ -680,6 +680,15 @@ public class JavaWriterTests {
         assertThat(string, equalTo("return 42;\nreturn 47;"));
     }
 
+    @Test
+    public void expressionStatement() throws IOException {
+        var java = new JavaExpressionStatement(new JavaIntegerLiteral(42));
+
+        var string = write(writer -> writer.writeBlockStatement(java));
+
+        assertThat(string, equalTo("42;"));
+    }
+
     @Test
     public void returnStatement() throws IOException {
         var java = new JavaReturn(new JavaIntegerLiteral(42));
-- 
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