initial commit: DBG! and function_name! macros

.gitignore

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+/target
+/Cargo.lock

Cargo.toml

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+[package]
+name = "rustics-dbg"
+version = "1.0.0"
+edition = "2021"
+
+[dependencies]

src/lib.rs

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+/// Exact copy from the stdext crate v0.3.1
+/// <https://docs.rs/stdext/0.3.1/stdext/macro.function_name.html>
+#[macro_export]
+macro_rules! function_name {
+    () => {{
+        // Okay, this is ugly, I get it. However, this is the best we can get on a stable rust.
+        fn f() {}
+        fn type_name_of<T>(_: T) -> &'static str {
+            std::any::type_name::<T>()
+        }
+        let name = type_name_of(f);
+        // `3` is the length of the `::f`.
+        &name[..name.len() - 3]
+    }};
+}
+
+/// Like [`println!`] but also prints the current function name (including module path) and line.
+///
+/// # Examples
+///
+/// ```
+/// use rustics_dbg::DBG;
+/// let x = 42;
+/// let y = "hello debug";
+/// DBG!("{} {}", x, y);
+/// ```
+///
+/// ```compile_fail
+/// use rustics_dbg::DBG;
+/// let x = 42;
+/// let y = "hello debug";
+/// // Since internally the macro uses concat!, you cannot inline variables into the format string.
+/// DBG!("{x} {y}"); // this won't compile
+/// ```
+#[macro_export]
+macro_rules! DBG {
+    ($fmt:literal $(,$arg:expr)*) => {
+        println!(concat!("{}():{} ", $fmt), $crate::function_name!(), line!() $(,$arg)*);
+    };
+}