use darling::ToTokens;
use syn::spanned::Spanned;
#[derive(Debug)]
pub struct StateDef {
pub index: usize,
pub attr_span: proc_macro2::Span,
pub ident: syn::Ident,
}
mod keyword {
syn::custom_keyword!(State);
}
impl StateDef {
pub fn try_from(
attr_span: proc_macro2::Span,
index: usize,
item: &mut syn::Item,
) -> syn::Result<Self> {
let item = if let syn::Item::Struct(item) = item {
item
} else {
let msg = "Invalid mashin::state, expected struct";
return Err(syn::Error::new(item.span(), msg))
};
if !matches!(item.vis, syn::Visibility::Public(_)) {
let msg = "Invalid mashin::state, struct must be public";
return Err(syn::Error::new(item.span(), msg))
}
syn::parse2::<keyword::State>(item.ident.to_token_stream())?;
Ok(Self { index, attr_span, ident: item.ident.clone() })
}
}