Derive `Cast` for enums

1 files changed, 10 insertions, 1 deletions

diff --git a/macros/src/lib.rs b/macros/src/lib.rs
index 889eaa7b..fafe8eea 100644
--- a/macros/src/lib.rs
+++ b/macros/src/lib.rs
@@ -15,7 +15,7 @@ use quote::quote;
 use syn::ext::IdentExt;
 use syn::parse::{Parse, ParseStream, Parser};
 use syn::punctuated::Punctuated;
-use syn::{parse_quote, Ident, Result, Token};
+use syn::{parse_quote, DeriveInput, Ident, Result, Token};
 
 use self::util::*;
 
@@ -35,6 +35,15 @@ pub fn node(stream: BoundaryStream, item: BoundaryStream) -> BoundaryStream {
         .into()
 }
 
+/// Implement `Cast` for an enum.
+#[proc_macro_derive(Cast, attributes(string))]
+pub fn cast(item: BoundaryStream) -> BoundaryStream {
+    let item = syn::parse_macro_input!(item as DeriveInput);
+    castable::cast(item)
+        .unwrap_or_else(|err| err.to_compile_error())
+        .into()
+}
+
 /// Implement `Cast` and optionally `Type` for a type.
 #[proc_macro]
 pub fn cast_from_value(stream: BoundaryStream) -> BoundaryStream {