chore: Add hello-world macro code

workflow/hello_world_macro/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "hello_world_macro"
+version = "0.0.1"
+edition = "2018"
+authors = ["HugoByte <[email protected]>"]
+repository = "https://github.com/HugoByte/internal-research-and-sample-code/tree/hello-world-workflow-macro"
+license = "Apache-2.0"
+description = "Derive macro for hello world workflow"
+
+[dependencies]
+quote = "1.0.33"
+syn = "2.0.29"
+
+[lib]
+proc-macro = true

workflow/hello_world_macro/src/lib.rs

@@ -0,0 +1,23 @@
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use syn::DeriveInput;
+
+#[proc_macro_derive(HelloWorldDerive)]
+pub fn hello_world_derive_macro(item: TokenStream) -> TokenStream {
+
+    let ast: DeriveInput = syn::parse(item).unwrap();
+    let ident = ast.ident;
+
+    // implement the function and return as TokenStream object
+    quote::quote! {
+        impl #ident{
+            pub fn run(&mut self) -> Result<(), String>{
+                self.output = serde_json::to_value(format!("Hello {}", self.input.name))
+                    .map_err(|e|e.to_string())?;
+                Ok(())
+            }
+        }
+    }
+    .into()
+}