Move to VTableBuilder for IntObj VTable, add __splat__ impl

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/obj/int.rs

@@ -11,11 +11,29 @@ pub struct IntObj {
     vtable: VTable,
 }
 
-impl IntObj {
-    pub fn new(value: Int) -> Gc<Self> {
 thread_local! {
-            static VTABLE: VTable = vtable! {
+    static VTABLE: VTable = VTableBuilder::default()
-                "__bool__" => builtin_fn!("__bool__", |machine, _| {
+        .with_builtin("__splat__", |machine, _| {
+            let rhs_ptr: ObjPtr = machine.stack_pop()?;
+            let lhs_ptr: ObjPtr = machine.stack_pop()?;
+            let lhs = lhs_ptr.as_any().downcast_ref::<IntObj>();
+            let rhs = rhs_ptr.as_any().downcast_ref::<IntObj>();
+            match (lhs, rhs) {
+                (Some(lhs), Some(rhs)) => {
+                    let result = IntObj::new(lhs.value() * rhs.value());
+                    machine.stack_push(result)?;
+                    Ok(BuiltinExit::Return)
+                }
+                (Some(_lhs), None) => {
+                    Err(RuntimeError::WrongValue("int value (rhs)".to_string()))
+                },
+                (None, Some(_rhs)) => {
+                    Err(RuntimeError::WrongValue("int value (lhs)".to_string()))
+                }
+                (None, None) => { panic!("called an int builtin with no int values at all"); }
+            }
+        })
+        .with_builtin("__bool__", |machine, _| {
             let obj_ptr: ObjPtr = machine.stack_pop()?;
             let obj: &(dyn Obj + 'static) = &*obj_ptr;
             if let Some(int) = obj.as_any().downcast_ref::<IntObj>() {
@@ -25,8 +43,8 @@ impl IntObj {
             } else {
                 Err(RuntimeError::WrongValue("int".to_string()))
             }
-                }),
+        })
-                "__str__" => builtin_fn!("__str__", |machine, _| {
+        .with_builtin("__str__", |machine, _| {
             let obj_ptr: ObjPtr = machine.stack_pop()?;
             let obj: &(dyn Obj + 'static) = &*obj_ptr;
             if let Some(int) = obj.as_any().downcast_ref::<IntObj>() {
@@ -36,9 +54,12 @@ impl IntObj {
             } else {
                 Err(RuntimeError::WrongValue("int".to_string()))
             }
-                }),
+        })
-            };
+        .finish();
-        };
+}
+
+impl IntObj {
+    pub fn new(value: Int) -> Gc<Self> {
         // TODO : intern int value
         Gc::new(IntObj {
             value,