From 3f8039bff09578fc3219503ca34a4d99833a7323 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 3 May 2026 12:00:38 +0100
Subject: Parse constructed types

---
 .../parser/ParserConstructedTypeTests.java         | 76 ++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserConstructedTypeTests.java

(limited to 'src/test/java/org/zwobble')

diff --git a/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserConstructedTypeTests.java b/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserConstructedTypeTests.java
new file mode 100644
index 0000000..1444cf0
--- /dev/null
+++ b/src/test/java/org/zwobble/hobgoblin/compiler/parser/ParserConstructedTypeTests.java
@@ -0,0 +1,76 @@
+package org.zwobble.hobgoblin.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedConstructedTypeNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelExpressionNode;
+import org.zwobble.hobgoblin.compiler.ast.untyped.UntypedTypeLevelReferenceNode;
+import org.zwobble.precisely.Matcher;
+
+import static org.zwobble.hobgoblin.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.*;
+
+public class ParserConstructedTypeTests {
+    @Test
+    public void canParseConstructedTypeWithOneArg() {
+        var source = "List[String]";
+
+        var node = parseString(source, Parser::parseTypeLevelExpression);
+
+        assertThat(node, isUntypedConstructedTypeNode(
+            isUntypedTypeLevelReferenceNode("List"),
+            isSequence(
+                isUntypedTypeLevelReferenceNode("String")
+            )
+        ));
+    }
+
+    @Test
+    public void canParseConstructedTypeWithMultipleArgs() {
+        var source = "X[T1, T2, T3]";
+
+        var node = parseString(source, Parser::parseTypeLevelExpression);
+
+        assertThat(node, isUntypedConstructedTypeNode(
+            isUntypedTypeLevelReferenceNode("X"),
+            isSequence(
+                isUntypedTypeLevelReferenceNode("T1"),
+                isUntypedTypeLevelReferenceNode("T2"),
+                isUntypedTypeLevelReferenceNode("T3")
+            )
+        ));
+    }
+
+    @Test
+    public void argsCanHaveTrailingComma() {
+        var source = "List[String,]";
+
+        var node = parseString(source, Parser::parseTypeLevelExpression);
+
+        assertThat(node, isUntypedConstructedTypeNode(
+            isUntypedTypeLevelReferenceNode("List"),
+            isSequence(
+                isUntypedTypeLevelReferenceNode("String")
+            )
+        ));
+    }
+
+    private static Matcher<UntypedTypeLevelExpressionNode> isUntypedConstructedTypeNode(
+        Matcher<UntypedTypeLevelExpressionNode> receiver,
+        Matcher<Iterable<? extends UntypedTypeLevelExpressionNode>> args
+    ) {
+        return instanceOf(
+            UntypedConstructedTypeNode.class,
+            has("receiver", UntypedConstructedTypeNode::receiver, receiver),
+            has("args", UntypedConstructedTypeNode::args, args)
+        );
+    }
+
+    private static Matcher<UntypedTypeLevelExpressionNode> isUntypedTypeLevelReferenceNode(String name) {
+        return instanceOf(
+            UntypedTypeLevelReferenceNode.class,
+            has("name", UntypedTypeLevelReferenceNode::name, equalTo(name))
+        );
+    }
+}
+
-- 
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