start of cbind proc_macro: just pulling out required elements from syn parse tree (name, fn name, ret type)

.gitignore

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+/target
+Cargo.lock
+.idea

Cargo.toml

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+[package]
+name = "cbinder"
+version = "0.1.0"
+edition = "2021"
+authors = ["Dan Ballard <dan@mindstab.net>"]
+license = "MIT"
+description = "proc-macro to generate memory safe rust native bindings from bindgen for Open Privacy c libraries"
+
+[lib]
+proc-macro = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+syn = { version = "1.0", features = ["full"] }
+quote = "1.0"
+regex = "1"

src/lib.rs

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+use proc_macro::TokenStream;
+
+use quote::quote;
+use syn;
+
+// cbind!(fn start_cwtch(app_dir: &str, tor_path: &str)  -> i32 {c_StartCwtch});
+#[proc_macro]
+pub fn cbind(_def: TokenStream) -> TokenStream {
+    //dbg!(&_def);
+    let ast: syn::ItemFn = syn::parse(_def).unwrap();
+
+    dbg!(&ast);
+
+    let fn_name = ast.sig.ident;
+    let fn_call = match &ast.block.stmts[0] {
+        syn::Stmt::Expr(expr) => match expr {
+            syn::Expr::Path(expr) => Ok(expr.path.segments[0].ident.to_string()),
+            _ => Err("".to_string()),
+        }
+        _ => Err("".to_string()),
+    };
+    let ret_type = match &ast.sig.output {
+        syn::ReturnType::Type(_, box_type) => {
+            let ty= &**box_type;
+            match ty {
+                syn::Type::Path(p) => {
+                    if p.path.segments.len() == 1 {
+                        Some(p.path.segments[0].ident.to_string())
+                    } else {
+                        None
+                    }
+                }
+                _ => None
+            }
+        }
+        _ => None
+    };
+
+    dbg!(fn_call);
+    dbg!(ret_type);
+    let args = ast.sig.inputs;
+
+    quote!(fn #fn_name(&self) {}).into()
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        let result = 2 + 2;
+        assert_eq!(result, 4);
+    }
+}