diff --git a/src/ast/types.rs b/src/ast/types.rs
index 777e5e8..e582c52 100644
--- a/src/ast/types.rs
+++ b/src/ast/types.rs
@@ -102,6 +102,7 @@ pub enum Value {
     Ref(Ref),
     Closure { env: EnvName, expr: Box<Expr> },
     PrimitiveFunc(Name),
+    Return(Box<Value>),
 }
 
 /// A mutable variable.
diff --git a/src/interpret/interpret.rs b/src/interpret/interpret.rs
index 5d09773..0dc7f27 100644
--- a/src/interpret/interpret.rs
+++ b/src/interpret/interpret.rs
@@ -101,21 +101,29 @@ fn eval_expr(expr_env: &Env, state: &mut State, expr: &ast::Expr) -> Result<ast:
         }
         ast::Expr::Block(statements) => {
             let mut block_env = expr_env.clone();
-            if let Some(last) = statements.iter().try_fold(None, |_, statement| {
-                let result = eval_statement(&mut block_env, state, statement)?;
-                match result {
-                    StatementResult::Result(result) => {
-                        Ok::<Option<ast::Value>, Error>(Some(result))
+            let mut result = ast::UNIT_VALUE;
+            for statement in statements {
+                let r = eval_statement(&mut block_env, state, statement)?;
+                match r {
+                    StatementResult::Result(ast::Value::Return(r)) => {
+                        result = ast::Value::Return(r);
+                        break;
                     }
-                    StatementResult::Return(result) => {
-                        Ok::<Option<ast::Value>, Error>(Some(result))
+                    StatementResult::Return(ast::Value::Return(r)) => {
+                        result = ast::Value::Return(r);
+                        break;
+                    }
+                    StatementResult::Result(r) => {
+                        result = r;
+                    }
+                    StatementResult::Return(r) => {
+                        result = ast::Value::Return(Box::new(r));
+                        break;
                     }
                 }
-            })? {
-                Ok(last)
-            } else {
-                Err(Error::LastStatementNotAnExpr(Backtrace::capture()))
             }
+
+            Ok(result)
         }
         ast::Expr::Access { expr, field } => match eval_expr(expr_env, state, expr)? {
             ast::Value::Record(record) => Ok(state.variables.get(record.get(&field)?).clone()),
@@ -148,7 +156,10 @@ fn eval_expr(expr_env: &Env, state: &mut State, expr: &ast::Expr) -> Result<ast:
                         let evalled = eval_expr(&closure_env, state, e)?;
                         closure_env.insert(arg.name, evalled);
                     }
-                    eval_expr(&closure_env, state, &func.body)
+                    match eval_expr(&closure_env, state, &func.body)? {
+                        ast::Value::Return(r) => Ok(*r),
+                        v => Ok(v),
+                    }
                 }
                 e => Err(Error::NotAFunction(e, Backtrace::capture())),
             },
diff --git a/src/lib.rs b/src/lib.rs
index b5e18b4..3a9b34c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -2,3 +2,69 @@ pub mod ast;
 pub mod interpret;
 pub mod parser;
 pub mod runtime;
+
+pub fn run_main(code: &str) -> Result<ast::Value, String> {
+    match parser::parse_file(code.into()) {
+        Err(err) => Err(format!("Error: {err:?}")),
+        Ok(program) => match interpret::run(program, "main".into(), vec![]) {
+            Ok(v) => Ok(v),
+            Err(err) => Err(format!("{}", err)),
+        },
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::run_main;
+
+    #[test]
+    fn int_108() {
+        let program = "
+let main = fn() {
+  108
+}
+";
+        let result = run_main(program);
+        insta::assert_debug_snapshot!(result);
+    }
+    #[test]
+    fn let_add_3() {
+        let program = "
+let main = fn() {
+  let a = 1;
+  let b = 2;
+  a + b
+}
+";
+        let result = run_main(program);
+        insta::assert_debug_snapshot!(result);
+    }
+    #[test]
+    fn let_if_4() {
+        let program = "
+let main = fn() {
+  let a = 1;
+  let b = if a > 0 { 3 } else { 5 };
+  a + b
+}
+";
+        let result = run_main(program);
+        insta::assert_debug_snapshot!(result);
+    }
+
+    #[test]
+    fn bor_onearm_4() {
+        let program = "
+let main = fn() {
+  let a = 1;
+  let b = 2 | 3;
+  if true {
+    return a + b;
+  };
+  return a;
+}
+";
+        let result = run_main(program);
+        insta::assert_debug_snapshot!(result);
+    }
+}
diff --git a/src/parser/types.rs b/src/parser/types.rs
index c835a2f..ddf780e 100644
--- a/src/parser/types.rs
+++ b/src/parser/types.rs
@@ -105,7 +105,7 @@ impl Tokens {
                 if let Some(_end) = self.next_if(end) {
                     Ok(Some(result))
                 } else {
-                    // println!("{:#?}", self);
+                    println!("{:#?}", self);
                     Err(Error::UnexpectedTokenForParser(
                         format!("between end {start:#?} and {end:#?}"),
                         self.next(),
diff --git a/src/snapshots/ayin__tests__bor_onearm_4.snap b/src/snapshots/ayin__tests__bor_onearm_4.snap
new file mode 100644
index 0000000..c4230c2
--- /dev/null
+++ b/src/snapshots/ayin__tests__bor_onearm_4.snap
@@ -0,0 +1,9 @@
+---
+source: src/lib.rs
+expression: result
+---
+Ok(
+    Int(
+        4,
+    ),
+)
diff --git a/src/snapshots/ayin__tests__int_108.snap b/src/snapshots/ayin__tests__int_108.snap
new file mode 100644
index 0000000..aa607b5
--- /dev/null
+++ b/src/snapshots/ayin__tests__int_108.snap
@@ -0,0 +1,9 @@
+---
+source: src/lib.rs
+expression: result
+---
+Ok(
+    Int(
+        108,
+    ),
+)
diff --git a/src/snapshots/ayin__tests__let_add_3.snap b/src/snapshots/ayin__tests__let_add_3.snap
new file mode 100644
index 0000000..ca8446c
--- /dev/null
+++ b/src/snapshots/ayin__tests__let_add_3.snap
@@ -0,0 +1,9 @@
+---
+source: src/lib.rs
+expression: result
+---
+Ok(
+    Int(
+        3,
+    ),
+)
diff --git a/src/snapshots/ayin__tests__let_if_4.snap b/src/snapshots/ayin__tests__let_if_4.snap
new file mode 100644
index 0000000..c4230c2
--- /dev/null
+++ b/src/snapshots/ayin__tests__let_if_4.snap
@@ -0,0 +1,9 @@
+---
+source: src/lib.rs
+expression: result
+---
+Ok(
+    Int(
+        4,
+    ),
+)