Link all top-level commands with macro recording/replaying logic

extract_derive/src/lib.rs

@@ -0,0 +1,53 @@
+use proc_macro::TokenStream;
+use syn::{spanned::Spanned, Data, Fields};
+
+#[proc_macro_derive(Extract)]
+pub fn extract(input: TokenStream) -> TokenStream {
+    let ast = syn::parse_macro_input!(input);
+
+    impl_extract(&ast)
+}
+
+fn impl_extract(ast: &syn::DeriveInput) -> TokenStream {
+    let name = &ast.ident;
+
+    match &ast.data {
+        // Dispatch over struct: extract args directly from context
+        Data::Struct(st) => match &st.fields {
+            Fields::Named(fields) => {
+                let extracted = fields.named.iter().map(|field| {
+                    let ident = &field.ident;
+                    let ty = &field.ty;
+
+                    quote::quote_spanned! {field.span()=>
+                        #ident : crate::utils::extract_arg!(ctx, #ident, #ty)
+                    }
+                });
+
+                TokenStream::from(quote::quote! {
+                    impl Extract for #name {
+                        fn extract(ctx: crate::ApplicationContext) -> Self {
+                            Self {
+                                #(#extracted,)*
+                            }
+                        }
+                    }
+                })
+            }
+            Fields::Unit => TokenStream::from(quote::quote! {
+                impl Extract for #name {
+                    fn extract(ctx: crate::ApplicationContext) -> Self {
+                        Self {}
+                    }
+                }
+            }),
+            _ => {
+                panic!("Only named/unit structs can derive Extract");
+            }
+        },
+
+        _ => {
+            panic!("Only structs can derive Extract");
+        }
+    }
+}