From 3f54b73a61e2fbe29e6e33dff4bb0b6e8bbf31f1 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 22 Apr 2026 11:34:09 +0100
Subject: Parse empty struct definitions

---
 .../zwobble/hobgoblin/compiler/parser/Parser.java  | 23 +++++++++++++++---
 .../hobgoblin/compiler/parser/TokenIterator.java   | 10 ++++++++
 .../parser/ParserStructDefinitionTests.java        | 27 ++++++++++++++++++++++
 3 files changed, 57 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserStructDefinitionTests.java

diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/parser/Parser.java b/src/main/java/org/zwobble/hobgoblin/compiler/parser/Parser.java
index 4411306..e90518c 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/parser/Parser.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/parser/Parser.java
@@ -1,8 +1,6 @@
 package org.zwobble.hobgoblin.compiler.parser;
 
-import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedNamespaceNode;
-import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelExpressionNode;
-import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelReferenceNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.*;
 import org.zwobble.hobgoblin.compiler.sources.FileFragmentSource;
 import org.zwobble.hobgoblin.compiler.sources.Source;
 import org.zwobble.hobgoblin.compiler.types.NamespaceName;
@@ -30,6 +28,25 @@ public class Parser {
         );
     }
 
+    public static UntypedNamespaceStatementNode parseNamespaceStatement(
+        TokenIterator tokens
+    ) {
+        var start = tokens.startPosition();
+
+        tokens.skip(TokenType.KEYWORD_STRUCT);
+        var name = tokens.next(TokenType.IDENTIFIER);
+        tokens.skip(TokenType.SYMBOL_BRACE_OPEN);
+        tokens.skip(TokenType.SYMBOL_BRACE_CLOSE);
+
+        var end = tokens.endPosition();
+        var source = createSource(start, end);
+
+        return new UntypedStructDefinitionNode(
+            name.charSequence().toString(),
+            source
+        );
+    }
+
     public static UntypedTypeLevelExpressionNode parseTypeLevelExpression(
         TokenIterator tokens
     ) {
diff --git a/src/main/java/org/zwobble/hobgoblin/compiler/parser/TokenIterator.java b/src/main/java/org/zwobble/hobgoblin/compiler/parser/TokenIterator.java
index cb59e79..177a87e 100644
--- a/src/main/java/org/zwobble/hobgoblin/compiler/parser/TokenIterator.java
+++ b/src/main/java/org/zwobble/hobgoblin/compiler/parser/TokenIterator.java
@@ -30,6 +30,16 @@ class TokenIterator {
         }
     }
 
+    public void skip(TokenType tokenType) {
+        var token = peek();
+        if (token.tokenType().equals(tokenType)) {
+            this.tokenIndex++;
+        } else {
+            // TODO: better expected string
+            throw new UnexpectedTokenError(tokenType.toString(), token);
+        }
+    }
+
     private Token getAbsolute(int index) {
         if (index < this.tokens.size()) {
             return this.tokens.get(index);
diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserStructDefinitionTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserStructDefinitionTests.java
new file mode 100644
index 0000000..8c692fd
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserStructDefinitionTests.java
@@ -0,0 +1,27 @@
+package org.zwobble.hobgoblin.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedStructDefinitionNode;
+
+import static org.zwobble.hobgoblin.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.*;
+
+public class ParserStructDefinitionTests {
+    @Test
+    public void emptyStruct() {
+        var source = """
+            struct Point {
+            }""";
+
+        var node = parseString(
+            source,
+            Parser::parseNamespaceStatement
+        );
+
+        assertThat(node, instanceOf(
+            UntypedStructDefinitionNode.class,
+            has("name", UntypedStructDefinitionNode::name, equalTo("Point"))
+        ));
+    }
+}
-- 
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