Handle precedence when parsing expressions

1 files changed, 42 insertions, 0 deletions

diff --git a/src/test/java/org/shedlang/compiler/parser/ParserPrecedenceTests.java b/src/test/java/org/shedlang/compiler/parser/ParserPrecedenceTests.java
new file mode 100644
index 00000000..471b46fe
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/parser/ParserPrecedenceTests.java
@@ -0,0 +1,42 @@
+package org.shedlang.compiler.parser;
+
+import org.junit.jupiter.api.Test;
+
+import static org.shedlang.compiler.ast.untyped.UntypedNodeMatchers.*;
+import static org.shedlang.compiler.parser.ParserTesting.parseString;
+import static org.zwobble.precisely.AssertThat.assertThat;
+
+public class ParserPrecedenceTests {
+    @Test
+    public void callHasHigherPrecedenceThanAddition() {
+        var source = "1 + f()";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedAddNode(
+                isUntypedIntLiteralNode(1),
+                isUntypedCallNode()
+                    .withReceiver(isUntypedReferenceNode("f"))
+            )
+        );
+    }
+    @Test
+    public void subtractionIsLeftAssociative() {
+        var source = "1 - 2 - 3";
+
+        var node = parseString(source, Parser::parseTopLevelExpression);
+
+        assertThat(
+            node,
+            isUntypedSubNode(
+                isUntypedSubNode(
+                    isUntypedIntLiteralNode(1),
+                    isUntypedIntLiteralNode(2)
+                ),
+                isUntypedIntLiteralNode(3)
+            )
+        );
+    }
+}