add derive macro for resource

gotham_restful_derive/src/resource.rs

@@ -0,0 +1,60 @@
+use crate::method::Method;
+use proc_macro::TokenStream;
+use proc_macro2::TokenStream as TokenStream2;
+use quote::quote;
+use syn::{
+	parse::{Parse, ParseStream, Result as SynResult},
+	punctuated::Punctuated,
+	token::Comma,
+	Ident,
+	ItemStruct,
+	parenthesized,
+	parse_macro_input
+};
+use std::str::FromStr;
+
+struct MethodList(Punctuated<Ident, Comma>);
+
+impl Parse for MethodList
+{
+	fn parse(input: ParseStream) -> SynResult<Self>
+	{
+		let content;
+		let _paren = parenthesized!(content in input);
+		let list : Punctuated<Ident, Comma> = Punctuated::parse_separated_nonempty(&content)?;
+		Ok(Self(list))
+	}
+}
+
+pub fn expand_resource(tokens : TokenStream) -> TokenStream
+{
+	let input = parse_macro_input!(tokens as ItemStruct);
+	let ident = input.ident;
+	
+	let methods : Vec<TokenStream2> = input.attrs.into_iter().filter(|attr|
+		attr.path.segments.iter().last().map(|segment| segment.ident.to_string()) == Some("rest_resource".to_string()) // TODO wtf
+	).flat_map(|attr| {
+		let m : MethodList = syn::parse2(attr.tokens).expect("unable to parse attributes");
+		m.0.into_iter()
+	}).map(|method| {
+		let method = Method::from_str(&method.to_string()).expect("unknown method");
+		let ident = method.setup_ident();
+		quote!(#ident(&mut route);)
+	}).collect();
+	
+	let output = quote! {
+		impl ::gotham_restful::Resource for #ident
+		{
+			fn name() -> String
+			{
+				stringify!(#ident).to_string()
+			}
+			
+			fn setup<D : ::gotham_restful::DrawResourceRoutes>(mut route : D)
+			{
+				#(#methods)*
+			}
+		}
+	};
+	output.into()
+}