add clap_layered

Cargo.toml

@@ -49,3 +49,11 @@ overflow-checks = false
 [[bench]]
 name = "bench_apis"
 harness = false
+
+[[example]]
+name = "clap_mini"
+path = "examples/rust/clap_mini.rs"
+
+[[example]]
+name = "clap_layered"
+path = "examples/rust/clap_layered.rs"

examples/rust/cfg.toml

@@ -0,0 +1,2 @@
+[example]
+param1 = "from config"

examples/rust/clap_layered.rs

@@ -0,0 +1,49 @@
+use std::path::Path;
+
+use clap::Parser;
+use config::{self, File};
+use hyperparameter::*;
+
+/// Defines the command-line arguments for the application.
+#[derive(Parser)]
+#[command(after_long_help=generate_params_help())]
+struct CommandLineArgs {
+    /// Specifies hyperparameters in the format `-D key=value` via the command line.
+    #[arg(short = 'D', long)]
+    define: Vec<String>,
+
+    /// Specifies the configuration file path.
+    #[arg(short = 'C', long, default_value = "examples/rust/cfg.toml")]
+    config: String,
+}
+
+fn main() {
+    let args = CommandLineArgs::parse();
+    let config_path = Path::new(&args.config);
+    let config = config::Config::builder()
+        .add_source(File::from(config_path))
+        .build()
+        .expect("Failed to load configuration file."); // Improved error handling
+
+    // No scope
+    println!(
+        "param1={} // Outside any specific scope",
+        get_param!(example.param1, "default".to_string())
+    );
+
+    with_params! { // Scope with configuration file parameters
+        params config.param_scope();
+
+        println!("param1={} // Within configuration file scope", get_param!(example.param1, "default".to_string()));
+        with_params! { // Scope with command-line arguments
+            params ParamScope::from(&args.define);
+
+            println!("param1={} // Within command-line arguments scope", get_param!(example.param1, "default".to_string(), "Example param1"));
+            with_params! { // User-defined scope
+                set example.param1= "scoped".to_string();
+
+                println!("param1={} // Within user-defined scope", get_param!(example.param1, "default".to_string()));
+            }
+        }
+    }
+}

examples/rust/clap_mini.rs

@@ -0,0 +1,22 @@
+use clap::Parser;
+use hyperparameter::*;
+
+/// Defines the command-line arguments for the application.
+#[derive(Parser)]
+#[command(after_long_help=generate_params_help())]
+struct CommandLineArgs {
+    /// Specifies hyperparameters in the format `-D key=value` via the command line.
+    #[arg(short = 'D', long)]
+    define: Vec<String>,
+}
+
+fn main() {
+    let args = CommandLineArgs::parse();
+    with_params! {
+        params ParamScope::from(&args.define);
+        // Retrieves `example.param1` with a default value of `1` if not specified.
+        println!("param1={}", get_param!(example.param1, 1));
+        // Displays a help message when `<app> --help` is executed.
+        println!("param2={}", get_param!(example.param2, false, "Example param2"));
+    }
+}

src/api.rs

@@ -7,7 +7,7 @@ use crate::storage::{
 use crate::value::{Value, EMPTY};
 use crate::xxh::XXHashable;
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum ParamScope {
     Nothing,
     Just(Tree),
@@ -180,9 +180,7 @@ macro_rules! get_param {
         {
             const CONST_HELP: &str = $help;
             #[::linkme::distributed_slice(PARAMS)]
-            static help: (&str, &str) = (
-                CONST_KEY, CONST_HELP
-            );
+            static help: (&str, &str) = (CONST_KEY, CONST_HELP);
         }
         THREAD_STORAGE.with(|ts| ts.borrow_mut().get_or_else(CONST_HASH, $default))
     }};
@@ -242,6 +240,18 @@ macro_rules! with_params {
         with_params!(params $ps; $($body)*)
     };
 
+    (
+        params $ps:expr;
+        params $nested:expr;
+
+        $($body:tt)*
+    ) => {
+        $ps.enter();
+        let ret = with_params!(params $nested; $($body)*);
+        $ps.exit();
+        ret
+    };
+
     (
         get $name:ident = $($key:ident).+ or $default:expr;
 
@@ -257,7 +267,6 @@ macro_rules! with_params {
 
         $($body:tt)*
     ) => {
-
         $ps.enter();
         let ret = {
             let $name = get_param!($($key).+, $default);
@@ -266,7 +275,6 @@ macro_rules! with_params {
         };
         $ps.exit();
         ret
-
     };
 
     (
@@ -279,6 +287,11 @@ macro_rules! with_params {
             $ps.exit();
             ret
     }};
+
+    ($($body:tt)*) => {{
+        let ret = {$($body)*};
+        ret
+    }};
 }
 
 #[macro_export]