Support of lifetimes in message struct

[paaaav]

Hello,

I'd like to specify lifetimes for a message. Manually implementing them works fine, so this is something the parser could support. See this reference

how it looks if done manually:

pub struct DropItem<'a> {
	bang: &'a mut Bang,
}

pub enum WeightMessages<'a> {
	DropItem(DropItem<'a>),
	TakeItem(TakeItem),
}

this library

pub struct DropItem<'a> {
	bang: &'a mut Bang,
}

transitions!(Weight,
  [
    (IsTaken, DropItem<'a>) => IsDropped,
    (IsDropped, DropItem<'a>) => IsDropped, 
    (IsDropped, TakeItem) => IsTaken,
    (IsTaken, TakeItem) => IsTaken
  ]
);

Thank you

[Geal]

hello, this should work with d5b806a
Additionally, it can accept generic types, as you can see in https://github.com/rust-bakery/machine/blob/master/tests/traffic_light.rs
I would advise that you do not abuse this feature, though, because I'm not sure it can work with all syntaxes (as an example, trait bounds would probably fail)

[paaaav]

Hi Geal,
this is a great start. Unfortunately I'm still keeping my own branch where I've completely removed this specific derive:

--- a/src/lib.rs
+++ b/src/lib.rs
@@ -724,7 +724,6 @@ pub fn transitions(input: proc_macro::TokenStream) -> syn::export::TokenStream {
 
     // define the state enum
     let toks = quote! {
-      #[derive(Clone,Debug,PartialEq)]
       pub enum #message_enum_ident #type_arg_toks {
         #(#variants_names(#structs_names)),*
       }

Why?

Let's say I have:

pub struct DropItem<'a> {
	object1: &'a mut Object,
	object2: &'a mut Object,
	component: &'a mut dyn Component,
}

then I need to implement Debug, Clone and PartialEq (Eq) for all of them, for every message struct. This is a lot of boilerplate. And then I still have the problem I can't do
component: &'a mut dyn Component+Clone, or deriving Clone for a trait object at all.

So that's why I've removed the derive. I haven't needed it so far.
I'm grateful that you've maintained this create and I don't know how other people would solve this -- could this derive be optional?
Thanks