Support undefined + null literals in vm

src/vstc/virtual_machine/bytecode_decoder.rs

@@ -1,6 +1,8 @@
 use std::rc::Rc;
 
 use super::vs_value::Val;
+use super::vs_undefined::VsUndefined;
+use super::vs_null::VsNull;
 use super::vs_number::VsNumber;
 use super::vs_string::VsString;
 use super::vs_pointer::VsPointer;
@@ -81,8 +83,8 @@ impl BytecodeDecoder {
 
     return match self.decode_type() {
       End => std::panic!("Cannot decode end"),
-      Undefined => std::panic!("Not implemented"),
-      Null => std::panic!("Not implemented"),
+      Undefined => VsUndefined::new(),
+      Null => VsNull::new(),
       False => std::panic!("Not implemented"),
       True => std::panic!("Not implemented"),
       SignedByte => VsNumber::from_f64(

src/vstc/virtual_machine/mod.rs

@@ -1,5 +1,6 @@
 mod vs_value;
 mod vs_undefined;
+mod vs_null;
 mod vs_bool;
 mod vs_number;
 mod vs_string;

src/vstc/virtual_machine/vs_null.rs

@@ -0,0 +1,40 @@
+use std::rc::Rc;
+
+use super::vs_value::Val;
+use super::vs_value::VsType;
+use super::vs_value::VsValue;
+use super::virtual_machine::StackFrame;
+
+pub struct VsNull {}
+
+impl VsNull {
+  pub fn new() -> Val {
+    return Rc::new(VsNull {});
+  }
+}
+
+impl VsValue for VsNull {
+  fn typeof_(&self) -> VsType {
+    return VsType::Null;
+  }
+
+  fn to_string(&self) -> String {
+    return "null".to_string();
+  }
+
+  fn to_number(&self) -> f64 {
+    return 0_f64;
+  }
+
+  fn is_primitive(&self) -> bool {
+    return true;
+  }
+
+  fn make_frame(&self) -> Option<StackFrame> {
+    return None;
+  }
+
+  fn is_truthy(&self) -> bool {
+    return false;
+  }
+}