Rust: make the cli flags override automatic

This makes the clap flags overlay over `Config` entirely derived via an
attribute macro. Also, the `--intputs-file` option is replaced by a more
standard and versatile `@` parameter file mechanism.

rust/extractor/macros/src/lib.rs

@@ -0,0 +1,52 @@
+use proc_macro::TokenStream;
+use quote::{quote, format_ident};
+use syn;
+
+
+/// Allow all fields in the extractor config to be also overrideable by extractor CLI flags
+#[proc_macro_attribute]
+pub fn extractor_cli_config(_attr: TokenStream, item: TokenStream) -> TokenStream {
+    let ast = syn::parse_macro_input!(item as syn::ItemStruct);
+    let name = &ast.ident;
+    let new_name = format_ident!("Cli{}", name);
+    let fields: Vec<_> = ast.fields.iter().map(|f| {
+        let id = f.ident.as_ref().unwrap();
+        let ty = &f.ty;
+        if let syn::Type::Path(p) = ty {
+            if p.path.is_ident(&format_ident!("bool")) {
+                return quote! {
+                    #[arg(long)]
+                    #id: bool,
+                };
+            }
+        }
+        if id == &format_ident!("verbose") {
+            quote! {
+                #[arg(long, short, action=clap::ArgAction::Count)]
+                #id: u8,
+            }
+        } else if id == &format_ident!("inputs") {
+            quote! {
+                #id: #ty,
+            }
+        } else {
+            quote! {
+                #[arg(long)]
+                #id: Option<#ty>,
+            }
+        }
+    }).collect();
+    let gen = quote! {
+        #[serde_with::apply(_ => #[serde(default)])]
+        #[derive(Debug, Deserialize, Default)]
+        #ast
+
+        #[serde_with::skip_serializing_none]
+        #[derive(clap::Parser, Serialize)]
+        #[command(about, long_about = None)]
+        struct #new_name {
+            #(#fields)*
+        }
+    };
+    gen.into()
+}