config macros: Make per-field skl variable an Option

So far, we never set it to None.  But this will allow us to abolish
the default, after we have srranged to always set it to Some.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/macros/macros.rs b/macros/macros.rs
index 9d64c245fb7a13d96d98d2fd1c48783054e58180..1233b4103d5fdd15c3c13a4e9b373192e9191f39 100644 (file)
--- a/macros/macros.rs
+++ b/macros/macros.rs
@@ -62,16 +62,16 @@ pub fn resolve(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     //dbg!(field);
     let fname = &field.ident.as_ref().unwrap();
     let fname_span = fname.span();
-    let mut skl = quote_spanned!{fname_span=> SectionKindList::PerClient };
+    let mut skl = Some(quote_spanned!{fname_span=> SectionKindList::PerClient });
     let mut method = quote_spanned!{fname_span=> ordinary };
     for attr in &field.attrs {
       let atspan = attr.path.segments.last().unwrap().ident.span();
       if attr.tokens.is_empty() {
         method = attr.path.to_token_stream();
         if &attr.path == &parse_quote!{ limited } {
-          skl = quote_spanned!{atspan=> SectionKindList::Limited };
+          skl = Some(quote_spanned!{atspan=> SectionKindList::Limited });
         } else if &attr.path == &parse_quote!{ computed } {
-          skl = quote_spanned!{atspan=> SectionKindList::None };
+          skl = Some(quote_spanned!{atspan=> SectionKindList::None });
         }
       } else if &attr.path == &parse_quote!{ special } {
         let meta = match attr.parse_meta().unwrap() {
@@ -86,11 +86,12 @@ pub fn resolve(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
           }
         }
         method = get_path(tmethod);
-        skl    = get_path(tskl);
+        skl = Some(get_path(tskl));
       }
     }
     let fname_string = fname.to_string();
     let fname_lit = Literal::string( &fname_string );
+    let skl = skl.expect(&format!("SKL not specified! (field {:?})!", fname));
 
     names.push(quote!{
       (#fname_lit, #skl),