Add #[patch_attribute(...)]] (#29)

.github/workflows/test.yml

@@ -23,6 +23,7 @@ jobs:
           nix develop -c cargo run --no-default-features --example diff
           nix develop -c cargo run --no-default-features --example json
           nix develop -c cargo run --no-default-features --example rename-patch-struct
+          nix develop -c cargo run --no-default-features --example patch-attr
           nix develop -c cargo test --no-default-features
 
       - name: Test with default features

Cargo.toml

@@ -6,7 +6,7 @@ members = [
 
 [workspace.package]
 authors = ["Antonio Yang <[email protected]>"]
-version = "0.5.0"
+version = "0.6.0"
 edition = "2021"
 categories = ["development-tools"]
 keywords = ["struct", "patch", "macro", "derive", "overlay"]

README.md

@@ -51,14 +51,15 @@ fn patch_json() {
 ```
 
 ## Documentation and Examples
-Also, you can modify the patch structure by `#[patch_derive(...)]`, `#[patch_name = "..."]` and `#[patch_skip]`.
+Also, you can modify the patch structure by `#[patch_attribute(...)]`, `#[patch_derive(...)]`, `#[patch_name = "..."]` and `#[patch_skip]`.
 Please check the [traits][doc-traits] of document to learn more.
 
 The [examples][examples] demo following scenarios.
 - diff two instance for a patch
 - create a patch from json string
 - rename the patch structure
 - check a patch is empty or not
+- add attribute to patch struct
 
 
 [crates-badge]: https://img.shields.io/crates/v/struct-patch.svg

struct-patch-derive/Cargo.toml

@@ -16,7 +16,7 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0"
-syn = { version =  "2.0", features = ["parsing"] }
+syn = { version =  "2.0", features = ["parsing", "extra-traits"] }
 
 [features]
 status = []

struct-patch-derive/src/lib.rs

@@ -1,13 +1,12 @@
 extern crate proc_macro;
-
 use std::str::FromStr;
 
 use proc_macro::TokenStream;
 use proc_macro2::{Ident, Span};
 use quote::quote;
 use syn::{DeriveInput, Expr, Lit, LitStr, Meta, MetaList, MetaNameValue, PathSegment, Type};
 
-#[proc_macro_derive(Patch, attributes(patch_derive, patch_name, patch_skip))]
+#[proc_macro_derive(Patch, attributes(patch_attribute, patch_derive, patch_name, patch_skip))]
 pub fn derive_patch(item: TokenStream) -> TokenStream {
     let DeriveInput {
         ident,
@@ -20,6 +19,7 @@ pub fn derive_patch(item: TokenStream) -> TokenStream {
     let where_clause = &generics.where_clause;
     let mut patch_struct_name: Option<Ident> = None;
     let mut patch_derive = None;
+    let mut patch_attrs = Vec::new();
 
     for attr in attrs {
         let mut attr_clone = attr.clone();
@@ -32,25 +32,40 @@ pub fn derive_patch(item: TokenStream) -> TokenStream {
             }) => {
                 let mut path_clone = path.clone();
                 let mut segments = path.segments.clone();
-                if let Some("patch_derive") = path
+                match path
                     .segments
                     .first()
                     .map(|s| s.ident.to_string())
                     .as_deref()
                 {
-                    if let Some(seg) = segments.first_mut() {
-                        *seg = PathSegment {
-                            ident: Ident::new("derive", Span::call_site()),
-                            arguments: seg.arguments.clone(),
-                        };
+                    Some("patch_derive") => {
+                        if let Some(seg) = segments.first_mut() {
+                            *seg = PathSegment {
+                                ident: Ident::new("derive", Span::call_site()),
+                                arguments: seg.arguments.clone(),
+                            };
+                        }
+                        path_clone.segments = segments;
+                        attr_clone.meta = Meta::List(MetaList {
+                            path: path_clone,
+                            tokens: tokens.clone(),
+                            delimiter: delimiter.clone(),
+                        });
+                        patch_derive = Some(attr_clone);
+                    },
+                    Some("patch_attribute") => {
+                        for token in tokens.to_string().split(',') {
+                            if ! token.is_empty() {
+                                let attr = proc_macro2::TokenStream::from_str(&format!("#[{}]", token)).expect("");
+                                patch_attrs.push(
+                                    quote::quote!(
+                                        #attr
+                                    )
+                                );
+                            }
+                        }
                     }
-                    path_clone.segments = segments;
-                    attr_clone.meta = Meta::List(MetaList {
-                        path: path_clone,
-                        tokens: tokens.clone(),
-                        delimiter: delimiter.clone(),
-                    });
-                    patch_derive = Some(attr_clone);
+                    _ => (),
                 }
             }
             Meta::NameValue(MetaNameValue {
@@ -185,12 +200,18 @@ pub fn derive_patch(item: TokenStream) -> TokenStream {
     let patch_struct = if let Some(patch_derive) = patch_derive {
         quote!(
             #patch_derive
+            #(
+                #patch_attrs
+            )*
             pub struct #patch_struct_name #generics #where_clause {
                 #(pub #field_names: #wrapped_types,)*
             }
         )
     } else {
         quote::quote!(
+            #(
+                #patch_attrs
+            )*
             pub struct #patch_struct_name #generics #where_clause {
                 #(pub #field_names: #wrapped_types,)*
             }

struct-patch/Cargo.toml

@@ -11,11 +11,12 @@ license.workspace = true
 readme.workspace = true
 
 [dependencies]
-struct-patch-derive = { version = "=0.5.0", path = "../struct-patch-derive" }
+struct-patch-derive = { version = "=0.6.0", path = "../struct-patch-derive" }
 
 [dev-dependencies]
 serde_json = "1.0"
 serde = { version = "1", features = ["derive"] }
+serde_with = "*"
 
 [features]
 default = ["status"]

struct-patch/examples/patch-attr.rs

@@ -0,0 +1,30 @@
+use struct_patch::Patch;
+use serde_with::skip_serializing_none;
+
+#[derive(Default, Patch)]
+#[patch_derive(serde::Serialize, Debug, Default)]
+#[patch_attribute(skip_serializing_none)]
+struct Item {
+    field_bool: bool,
+    field_int: usize,
+    field_string: String,
+}
+
+// Generated by Patch derive macro
+//
+// #[derive(Debug, Default)] // pass by patch_derive
+// #[skip_serializing_none] // pass by patch_attribute
+// struct ItemPatch {  // pass by patch_name
+//     field_bool: Option<bool>,
+//     field_int: Option<usize>,
+//     field_string: Option<String>,
+// }
+
+fn main() {
+    let patch = Item::new_empty_patch();
+
+    assert_eq!(
+        format!("{patch:?}"),
+        "ItemPatch { field_bool: None, field_int: None, field_string: None }"
+    );
+}

struct-patch/src/traits.rs

@@ -32,6 +32,22 @@
 /// // struct ItemPatch {}
 /// ```
 ///
+/// ### `#[patch_attribute(...)]`
+/// Use this attribute to pass the attributes on the generated patch struct
+/// ```compile_fail
+/// // This example need `serde` and `serde_with` crates
+/// # use struct_patch::Patch;
+/// #[derive(Patch, Debug)]
+/// #[patch_derive(Serialize, Deserialize, Default)]
+/// #[patch_attribute(skip_serializing_none)]
+/// struct Item;
+///
+/// // Generated struct
+/// // #[derive(Default, Deserialize, Serialize)]
+/// // #[skip_serializing_none]
+/// // struct ItemPatch {}
+/// ```
+///
 /// ### `#[patch_name = "..."]`
 /// Use this attribute to change the name of the generated patch struct
 /// ```rust