Define struct to represent template metadata

1 files changed, 23 insertions, 9 deletions

diff --git a/askama_derive/src/lib.rs b/askama_derive/src/lib.rs
index 367f124..fb3bb2d 100644
--- a/askama_derive/src/lib.rs
+++ b/askama_derive/src/lib.rs
@@ -4,19 +4,33 @@ extern crate syn;
 
 use proc_macro::TokenStream;
 
-fn get_path_from_attrs(attrs: &[syn::Attribute]) -> String {
+struct TemplateMeta {
+    path: String,
+}
+
+fn get_path_from_attrs(attrs: &[syn::Attribute]) -> TemplateMeta {
+    let mut path = None;
     let attr = attrs.iter().find(|a| a.name() == "template").unwrap();
     if let syn::MetaItem::List(_, ref inner) = attr.value {
-        if let syn::NestedMetaItem::MetaItem(ref item) = inner[0] {
-            if let &syn::MetaItem::NameValue(ref key, ref val) = item {
-                assert_eq!(key.as_ref(), "path");
-                if let &syn::Lit::Str(ref s, _) = val {
-                    return s.clone();
+        for nm_item in inner {
+            if let &syn::NestedMetaItem::MetaItem(ref item) = nm_item {
+                if let &syn::MetaItem::NameValue(ref key, ref val) = item {
+                    match key.as_ref() {
+                        "path" => if let &syn::Lit::Str(ref s, _) = val {
+                            path = Some(s.clone());
+                        } else {
+                            panic!("template path must be string literal");
+                        },
+                        _ => { panic!("unsupported annotation key found") }
+                    }
                 }
             }
         }
     }
-    panic!("template path not found in struct attributes");
+    if path.is_none() {
+        panic!("template path not found in struct attributes");
+    }
+    TemplateMeta { path: path.unwrap() }
 }
 
 #[proc_macro_derive(Template, attributes(template))]
@@ -26,6 +40,6 @@ pub fn derive_template(input: TokenStream) -> TokenStream {
         syn::Body::Struct(ref data) => data,
         _ => panic!("#[derive(Template)] can only be used with structs"),
     };
-    let path = get_path_from_attrs(&ast.attrs);
-    askama::build_template(&path, &ast).parse().unwrap()
+    let meta = get_path_from_attrs(&ast.attrs);
+    askama::build_template(&meta.path, &ast).parse().unwrap()
 }