flatten the instruction dispatch loop

crates/to-syn-value_derive/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "to-syn-value_derive"
+version = "0.1.0"
+authors = ["Mark Thom <markjordanthom@gmail.com>"]
+edition = "2021"
+publish = false
+
+[lib]
+proc-macro = true
+
+[dependencies]
+proc-macro2 = "*"
+syn = { version = "*", features = ['full', 'visit', 'extra-traits'] }
+quote = "*"

crates/to-syn-value_derive/src/lib.rs

@@ -0,0 +1,20 @@
+use syn::*;
+use quote::*;
+
+#[proc_macro_derive(ToDeriveInput)]
+pub fn derive_to_derive_input(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let derive_input = parse_macro_input!(input as DeriveInput);
+    let ty_name = derive_input.ident.clone();
+
+    quote! {
+        use to_syn_value::*;
+
+        impl ToDeriveInput for #ty_name {
+            fn to_derive_input() -> syn::DeriveInput {
+                syn::parse_quote! {
+                    #derive_input
+                }
+            }
+        }
+    }.into()
+}