From cbddf70ac35cd338dc60e1f5cffc10b4d9f71347 Mon Sep 17 00:00:00 2001
From: Ross Andrews <ross.andrews@gmail.com>
Date: Sat, 2 Sep 2023 00:39:56 -0500
Subject: [PATCH] Compiling return statements

---
 forge_core/src/compiler.rs | 39 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/forge_core/src/compiler.rs b/forge_core/src/compiler.rs
index 9e94ffc..f4dca17 100644
--- a/forge_core/src/compiler.rs
+++ b/forge_core/src/compiler.rs
@@ -235,7 +235,15 @@ impl Compilable for Block {
         for stmt in self.0 {
             let loc = stmt.location;
             match stmt.ast {
-                Statement::Return(_) => {}
+                Statement::Return(Return(None)) => {
+                    // Returning nothing, so just default to returning a 0:
+                    sig.emit_arg("ret", 0)
+                }
+                Statement::Return(Return(Some(expr))) => {
+                    // Eval the expr and emit a ret for it
+                    expr.process(state, Some(sig), loc)?;
+                    sig.emit("ret")
+                }
                 Statement::Assignment(assign) => assign.process(state, Some(sig), loc)?,
                 Statement::Expr(expr) => {
                     expr.process(state, Some(sig), loc)?;
@@ -1045,4 +1053,33 @@ mod test {
                 .join("\n")
         );
     }
+
+    #[test]
+    fn test_returns() {
+        assert_eq!(
+            test_body(state_for("fn test(a) { return a + 3; }")),
+            vec![
+                "loadw frame", // Load a
+                "loadw",
+                "push 3", // Add 3
+                "add",
+                "ret", // Return that
+            ]
+                .join("\n")
+        );
+
+        assert_eq!(
+            test_body(state_for("fn test(a) { if (a > 0) { return; } }")),
+            vec![
+                "loadw frame", // Load a
+                "loadw",
+                "push 0", // Compare to 0
+                "agt",
+                "#if", // If statement
+                "ret 0", // Default return value, for an expr-less return
+                "#end",
+            ]
+                .join("\n")
+        );
+    }
 }