allow deriving enums

gotham_restful_derive/src/openapi_type.rs

@@ -4,10 +4,66 @@ use quote::quote;
 use syn::{
 	Field,
 	Fields,
+	Item,
+	ItemEnum,
 	ItemStruct,
+	Variant,
 	parse_macro_input
 };
 
+pub fn expand(tokens : TokenStream) -> TokenStream
+{
+	let input = parse_macro_input!(tokens as Item);
+	
+	match input {
+		Item::Enum(item) => expand_enum(item),
+		Item::Struct(item) => expand_struct(item),
+		_ => panic!("derive(OpenapiType) not supported for this context")
+	}.into()
+}
+
+fn expand_variant(variant : &Variant) -> TokenStream2
+{
+	if variant.fields != Fields::Unit
+	{
+		panic!("Enum Variants with Fields not supported");
+	}
+	
+	let ident = &variant.ident;
+	
+	quote! {
+		enumeration.push(stringify!(#ident).to_string());
+	}
+}
+
+fn expand_enum(input : ItemEnum) -> TokenStream2
+{
+	let ident = input.ident;
+	let generics = input.generics;
+	
+	let variants : Vec<TokenStream2> = input.variants.iter().map(expand_variant).collect();
+	
+	quote! {
+		impl #generics ::gotham_restful::OpenapiType for #ident #generics
+		{
+			fn to_schema() -> ::gotham_restful::OpenapiSchema
+			{
+				use ::gotham_restful::{helper::openapi::*, OpenapiSchema};
+				
+				let mut enumeration : Vec<String> = Vec::new();
+				
+				#(#variants)*
+				
+				OpenapiSchema::new(SchemaKind::Type(Type::String(StringType {
+					format: VariantOrUnknownOrEmpty::Empty,
+					pattern: None,
+					enumeration
+				})))
+			}
+		}
+	}
+}
+
 fn expand_field(field : &Field) -> TokenStream2
 {
 	let ident = match &field.ident {
@@ -48,10 +104,8 @@ fn expand_field(field : &Field) -> TokenStream2
 	}}
 }
 
-pub fn expand(tokens : TokenStream) -> TokenStream
+pub fn expand_struct(input : ItemStruct) -> TokenStream2
 {
-	let input = parse_macro_input!(tokens as ItemStruct);
-	
 	let ident = input.ident;
 	let generics = input.generics;
 	
@@ -63,7 +117,7 @@ pub fn expand(tokens : TokenStream) -> TokenStream
 		Fields::Unit => Vec::new()
 	};
 	
-	let output = quote!{
+	quote!{
 		impl #generics ::gotham_restful::OpenapiType for #ident #generics
 		{
 			fn to_schema() -> ::gotham_restful::OpenapiSchema
@@ -92,7 +146,5 @@ pub fn expand(tokens : TokenStream) -> TokenStream
 				}
 			}
 		}
-	};
-	
-	output.into()
+	}
 }