uses a proc-macro to automate command definitions

api-proc-macro/tests/into_command_definition/union_fails.rs

@@ -0,0 +1,12 @@
+use api_proc_macro::IntoCommandDefinition;
+
+#[derive(IntoCommandDefinition)]
+#[repr(C)]
+union TestUnion {
+    f1: u32,
+    f2: f32,
+}
+
+fn main() {
+
+}