Add is_truthy

src/vstc/virtual_machine/vs_function.rs

@@ -51,4 +51,8 @@ impl VsValue for VsFunction {
 
     return true;
   }
+
+  fn is_truthy(&self) -> bool {
+    return true;
+  }
 }

src/vstc/virtual_machine/vs_number.rs

@@ -35,4 +35,8 @@ impl VsValue for VsNumber {
   fn push_frame(&self, vm: &mut VirtualMachine) -> bool {
     return false;
   }
+
+  fn is_truthy(&self) -> bool {
+    return self.value != 0_f64;
+  }
 }

src/vstc/virtual_machine/vs_pointer.rs

@@ -93,4 +93,8 @@ impl VsValue for VsPointer {
   fn push_frame(&self, vm: &mut VirtualMachine) -> bool {
     return self.decode().push_frame(vm);
   }
+
+  fn is_truthy(&self) -> bool {
+    return self.decode().is_truthy();
+  }
 }

src/vstc/virtual_machine/vs_string.rs

@@ -39,4 +39,8 @@ impl VsValue for VsString {
   fn push_frame(&self, vm: &mut VirtualMachine) -> bool {
     return false;
   }
+
+  fn is_truthy(&self) -> bool {
+    return self.value != "";
+  }
 }

src/vstc/virtual_machine/vs_undefined.rs

@@ -33,4 +33,8 @@ impl VsValue for VsUndefined {
   fn push_frame(&self, vm: &mut VirtualMachine) -> bool {
     return false;
   }
+
+  fn is_truthy(&self) -> bool {
+    return false;
+  }
 }

src/vstc/virtual_machine/vs_value.rs

@@ -37,6 +37,7 @@ pub trait VsValue {
   fn to_string(&self) -> String;
   fn to_number(&self) -> f64;
   fn is_primitive(&self) -> bool;
+  fn is_truthy(&self) -> bool;
 
   fn push_frame(&self, vm: &mut VirtualMachine) -> bool;
 }