docs: Update docs

README.md

@@ -38,7 +38,21 @@ The macro will also implement some traits for bitwise operations and formatting.
 - [X] Clone
 - [X] Copy
 
-Besides the `Debug`, `Clone` and `Copy` traits, all other derivable traits can be used together with the type.
+Besides the `Debug`, `Clone` and `Copy` traits, all other standard derivable traits can be used together with the type.
+
+The macro also generate iterator types to iterate over the set flags, and for convenience also implement the following traits:
+
+- [X] core::iter::Extend
+- [X] core::iter::FromIterator
+- [X] core::iter::Iterator (for the type and reference)
+
+There is a opt-in crate feature `serde` that generate a parsing error type and implements the traits:
+
+- [X] core::str::FromStr
+- [X] serde::Serialize
+- [X] serde::Deserialize
+
+**Note:** This crate does not import/re-export serde traits, your project MUST have `serde` as dependency.
 
 ## Example
 

src/lib.rs

@@ -11,11 +11,21 @@ use syn::{parse::Parse, punctuated::Punctuated, Error, Ident, ItemEnum, Result,
 /// This macro generates some trait implementations: [`fmt::Debug`], [`ops:Not`], [`ops:BitAnd`],
 /// [`ops:BitOr`], [`ops:BitXor`], [`ops:BitAndAssign`], [`ops:BitOrAssign`], [`ops:BitXorAssign`],
 /// [`fmt::Binary`], [`fmt::LowerHex`], [`fmt::UpperHex`], [`fmt::Octal`], [`From`], [`Clone`],
-/// [`Copy`]
+/// [`Copy`], [`Extend`], [`FromIterator`], [`IntoIterator`]
 ///
 /// If the macro receives `no_auto_debug`, the trait [`fmt::Debug`] will not be generated. Use this
 /// flag when you want to implement [`fmt::Debug`] manually or use the standard derive.
 ///
+/// ## Serde feature
+///
+/// If the crate is compiled with the `serde` feature, this crate will generate implementations for
+/// the `serde::{Serialize, Deserialize}` traits, but it will not import/re-export these traits,
+/// your project must have `serde` as dependency.
+///
+/// Having this feature enabled will also generate a type to represent the parsing error and helper
+/// functions to do parsing the generated type from strings. And will generate the implementation
+/// for the [`FromStr`] trait.
+///
 /// # Example
 ///
 /// ```
@@ -81,6 +91,7 @@ use syn::{parse::Parse, punctuated::Punctuated, Error, Ident, ItemEnum, Result,
 /// [`fmt::UpperHex`]: core::fmt::UpperHex
 /// [`fmt::Octal`]: core::fmt::Octal
 /// [`From`]: From
+/// [`FromStr`]: core::str::FromStr
 #[proc_macro_attribute]
 pub fn bitflag(attr: TokenStream, item: TokenStream) -> TokenStream {
     match bitflag_impl(attr, item) {