WIP on logging proc macro

Cargo.toml

@@ -1,3 +1,3 @@
 [workspace]
-members = ["copper", "copper_derive", "copper_derive_test", "examples/config-gen", "examples/pluginload", "examples/simplelogger", "examples/v4lsrc"]
+members = ["copper", "copper_derive", "copper_derive_test", "copper_log", "examples/config-gen", "examples/pluginload", "examples/simplelogger", "examples/v4lsrc"]
 resolver = "2"

copper_derive_test/Cargo.toml

@@ -8,6 +8,7 @@ copper-derive = { path = "../copper_derive" }
 simplelogger = { path = "../examples/simplelogger" }
 v4lsrc = { path = "../examples/v4lsrc" }
 copper = { path = "../copper" }
+copper-log = { path = "../copper_log" }
 
 [build-dependencies]
 copper = { path = "../copper" }

copper_derive_test/src/main.rs

@@ -1,8 +1,11 @@
 use copper_derive::copper_runtime;
+use copper_log::debug;
 
 #[copper_runtime(config = "copperconfig.ron")]
 struct MyApplication {}
 
 fn main() {
+    debug!("Application created.");
     let application = MyApplication::new().expect("Failed to create runtime.");
+    debug!("End of program.");
 }

copper_log/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "copper-log"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+proc-macro = true
+
+
+[dependencies]
+proc-macro2 = { version = "1.0.83", features = ["span-locations"] }
+quote = "1.0.36"
+syn = { version = "2.0.65", features = ["full"] }

copper_log/build.rs

@@ -0,0 +1,6 @@
+use std::env;
+
+fn main() {
+    let out_dir = env::var("OUT_DIR").unwrap();
+    println!("cargo:rustc-env=OUT_DIR={}", out_dir);
+}

copper_log/src/lib.rs

@@ -0,0 +1,26 @@
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use proc_macro2::Span;
+use quote::quote;
+use syn::{parse_macro_input, LitStr};
+
+#[proc_macro]
+pub fn debug(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as LitStr);
+    let message = input.value();
+
+    let expanded = quote! {
+        {
+            let log_message = #message;
+            println!("Log: {:?}", log_message);
+            log_message
+        }
+    };
+    println!("Found logging string {}", message);
+
+    // print the OUT env vairable
+    println!("OUT: {}", std::env::var("OUT_DIR").unwrap());
+
+    TokenStream::from(expanded)
+}