Added proc macro sample

Author: buraksenyurt

Cargo.toml

@@ -1,4 +1,4 @@
 [workspace]
-members = ["Lesson_00", "Lesson_01", "Lesson_02", "Lesson_03", "Lesson_04", "Lesson_05", "Lesson_06", "Lesson_07", "Lesson_08", "Lesson_09", "Lesson_10", "Lesson_11", "Lesson_12", "Lesson_13", "collector", "drone-lab", "fops", "game-engine", "mocking", "router", "sysco", "sysco2"]
+members = ["Lesson_00", "Lesson_01", "Lesson_02", "Lesson_03", "Lesson_04", "Lesson_05", "Lesson_06", "Lesson_07", "Lesson_08", "Lesson_09", "Lesson_10", "Lesson_11", "Lesson_12", "Lesson_13", "collector", "drone-lab", "fops", "game-engine", "mocking", "procs", "router", "sysco", "sysco2"]
 
 resolver = "2"

Lesson_13/Cargo.toml

@@ -4,3 +4,4 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+procs = { path = "../procs" }

Lesson_13/src/main.rs

@@ -1,3 +1,16 @@
 mod samples;
 
-fn main() {}
+use procs::work_time_effort;
+
+#[work_time_effort]
+fn find_total() {
+    let mut total = 0;
+    for i in 0..1000 {
+        total += i;
+    }
+    println!("Result: {}", total);
+}
+
+fn main() {
+    let _total = find_total();
+}

procs/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "procs"
+description = "Sample procedural macros for training"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+proc-macro = true
+
+[dependencies]
+quote = "1.0.40"
+syn = { version = "2.0.101", features = ["full"] }

procs/src/lib.rs

@@ -0,0 +1,23 @@
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{ItemFn, parse_macro_input};
+
+#[proc_macro_attribute]
+pub fn work_time_effort(_attr: TokenStream, item: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(item as ItemFn);
+    let fn_name = &input.sig.ident;
+    let fn_block = &input.block;
+
+    let expanded = quote! {
+        fn #fn_name() {
+            let start = std::time::Instant::now();
+            #fn_block
+            let duration = start.elapsed();
+            println!("Total execution time {}: {:?}", stringify!(#fn_name), duration);
+        }
+    };
+
+    expanded.into()
+}