From 88831fb3f83810cd234b0e871b02c4b9f539c1b8 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Fri, 7 Jul 2023 18:47:55 +0100
Subject: Type check integer subtraction

---
 .../compiler/ast/typed/TypedNodeMatchers.java      | 27 +++++++++++++++++-----
 .../org/shedlang/compiler/ast/untyped/Untyped.java | 12 ++++++++++
 .../TypeCheckerBinaryOperationTests.java           | 16 +++++++++++--
 3 files changed, 47 insertions(+), 8 deletions(-)

(limited to 'src/test/java')

diff --git a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
index 69acee24..22da82bf 100644
--- a/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
+++ b/src/test/java/org/shedlang/compiler/ast/typed/TypedNodeMatchers.java
@@ -16,6 +16,19 @@ public class TypedNodeMatchers {
         return TypedArgsNodeMatcher.empty();
     }
 
+    public static Matcher<TypedExpressionNode> isTypedBinaryOperationNode(
+        TypedBinaryOperator operator,
+        Matcher<TypedExpressionNode> left,
+        Matcher<TypedExpressionNode> right
+    ) {
+        return instanceOf(
+            TypedBinaryOperationNode.class,
+            has("operator", x -> x.operator(), equalTo(operator)),
+            has("left", x -> x.left(), left),
+            has("right", x -> x.right(), right)
+        );
+    }
+
     public static Matcher<TypedExpressionNode> isTypedBoolLiteralNode(boolean value) {
         return instanceOf(
             TypedBoolLiteralNode.class,
@@ -44,12 +57,7 @@ public class TypedNodeMatchers {
         Matcher<TypedExpressionNode> left,
         Matcher<TypedExpressionNode> right
     ) {
-        return instanceOf(
-            TypedBinaryOperationNode.class,
-            has("operator", x -> x.operator(), equalTo(TypedBinaryOperator.INT_ADD)),
-            has("left", x -> x.left(), left),
-            has("right", x -> x.right(), right)
-        );
+        return isTypedBinaryOperationNode(TypedBinaryOperator.INT_ADD, left, right);
     }
 
     public static Matcher<TypedExpressionNode> isTypedIntLiteralNode(int value) {
@@ -63,6 +71,13 @@ public class TypedNodeMatchers {
         );
     }
 
+    public static Matcher<TypedExpressionNode> isTypedIntSubNode(
+        Matcher<TypedExpressionNode> left,
+        Matcher<TypedExpressionNode> right
+    ) {
+        return isTypedBinaryOperationNode(TypedBinaryOperator.INT_SUB, left, right);
+    }
+
     public static Matcher<TypedNamedArgNode> isTypedNamedArgNode(
         String name,
         Matcher<TypedExpressionNode> expression
diff --git a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
index a5a61303..b0cce55e 100644
--- a/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
+++ b/src/test/java/org/shedlang/compiler/ast/untyped/Untyped.java
@@ -85,6 +85,18 @@ public class Untyped {
         return new UntypedStringLiteralNode(value, Sources.NULL);
     }
 
+    public static UntypedBinaryOperationNode sub(
+        UntypedExpressionNode left,
+        UntypedExpressionNode right
+    ) {
+        return new UntypedBinaryOperationNode(
+            UntypedBinaryOperator.SUB,
+            left,
+            right,
+            Sources.NULL
+        );
+    }
+
     public static UntypedTargetNode targetVariable(String name) {
         return new UntypedTargetNode.Variable(name, Sources.NULL);
     }
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
index 017c2d97..98dd8679 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerBinaryOperationTests.java
@@ -4,8 +4,7 @@ import org.junit.jupiter.api.Test;
 import org.shedlang.compiler.ast.untyped.Untyped;
 import org.shedlang.compiler.types.Types;
 
-import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.isTypedIntAddNode;
-import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.isTypedIntLiteralNode;
+import static org.shedlang.compiler.ast.typed.TypedNodeMatchers.*;
 import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.equalTo;
 
@@ -22,4 +21,17 @@ public class TypeCheckerBinaryOperationTests {
         ));
         assertThat(typed.value().type(), equalTo(Types.INT));
     }
+
+    @Test
+    public void whenBothOperandsAreIntsAndOperatorIsSubThenIsTypedAsIntSub() {
+        var untyped = Untyped.sub(Untyped.intLiteral(42), Untyped.intLiteral(47));
+
+        var typed = TypeChecker.typeCheckExpression(untyped, TypeCheckerContext.EMPTY);
+
+        assertThat(typed.value(), isTypedIntSubNode(
+            isTypedIntLiteralNode(42),
+            isTypedIntLiteralNode(47)
+        ));
+        assertThat(typed.value().type(), equalTo(Types.INT));
+    }
 }
-- 
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