chore: add kloud_entries_macro_derive

kloud_entries_macro_derive/src/lib.rs

@@ -0,0 +1,69 @@
+extern crate proc_macro;
+extern crate syn;
+// #[macro_use]
+extern crate quote;
+
+// use std::collections::BTreeMap;
+
+use proc_macro::{TokenStream};
+use syn::{parse_macro_input, DeriveInput };
+use quote::quote;
+// use proc_macro2::{Span, TokenStream};
+// use syn::{parse_macro_input, Attribute, DeriveInput, Ident, Result};
+// use proc_macro::TokenStream;
+
+// #[proc_macro_derive(KloudEntries, attributes(kloud_entries))]  // It does not work from caller
+#[proc_macro_derive(KloudEntries)]
+pub fn kloud_entries_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    // Construct a representation of Rust code as a syntax tree
+    // that we can manipulate
+    // let ast = syn::parse(input).unwrap();
+    // // Build the trait implementation
+    // impl_kloud_entries(&ast).into()
+    let input = parse_macro_input!(input as DeriveInput);
+    // proc_macro::TokenStream::from(impl_kloud_entries(&input))
+    impl_kloud_entries(&input)
+}
+
+fn impl_kloud_entries(ast: &syn::DeriveInput) -> TokenStream {
+    let name = &ast.ident;
+    // let attrs = &ast.attrs;
+    // eprintln!("{:#?}",&attrs);
+    // let name_items = &format!("{}Items",&ast.ident);
+    let gen = quote! {
+      impl KloudEntries for #name {
+        fn load_content_data(content: &str, frmt: &str) -> Vec<#name> {
+          match frmt {
+            "yaml" => ::serde_yaml::from_str(&content)
+              .unwrap_or_else(|e| {
+                eprintln!();
+                Vec::new()
+              }),
+            "json" => ::serde_json::from_str(&content)
+              .unwrap_or_else(|e| {
+                eprintln!();
+                Vec::new()
+              }),
+            "toml" => ::toml::from_str(&content)
+              .unwrap_or_else(|e| {
+                eprintln!();
+                Vec::new()
+              }),
+            _ => Vec::new(),
+          }
+        }
+        fn data_map_to_content(data_map: BTreeMap<String,#name>, frmt: &str) -> Result<String> { 
+          Ok(match frmt {
+            "toml" => toml::to_string_pretty(&data_map)
+              .context("Failed to 'string' loaded data")?,
+            "yaml" => serde_yaml::to_string(&data_map)
+              .context("Failed to 'string' loaded data")?,
+            "json" => serde_json::to_string_pretty(&data_map)
+             .context("Failed to 'string' loaded data")?,
+            _  =>  String::from(""),
+          })
+        }
+      }
+    };
+    gen.into()
+}