Add #[bitmap_attr] attribute macro

- Implements feature requested in issue #8
- Provides alternative syntax to bitmap! macro
- Both macros generate identical code and functionality
- Added comprehensive tests to verify compatibility
- Updated README with usage examples

Author: RabbitAlbatross

README.md

@@ -64,6 +64,29 @@ assert_eq!(player.finished_tasks(), 5);
 assert_eq!(player.kills(), 3);
 assert_eq!(*player, 0b01101011);
 ```
+## `#[bitmap_attr]` Attribute Macro
+
+If you prefer attribute macro syntax, you can use `#[bitmap_attr]` instead of `bitmap!`. Both work exactly the same way.
+
+```rust
+use bitmap::bitmap_attr;
+
+#[bitmap_attr]
+struct Player {
+    imposter: u1,
+    finished_tasks: u3,
+    kills: u3,
+}
+
+let mut player = Player(0);
+player.set_imposter(1)
+    .set_finished_tasks(5)
+    .set_kills(3);
+
+assert_eq!(player.imposter(), 1);
+assert_eq!(player.finished_tasks(), 5);
+assert_eq!(player.kills(), 3);
+}
 
 ### Accessing fields
 

macros/src/lib.rs

@@ -1,7 +1,7 @@
 use proc_macro::TokenStream;
 use syn::parse_macro_input;
 use syn::DeriveInput;  
-use quote::quote;      
+      
 use quote::ToTokens;  
 
 mod generator;
@@ -133,7 +133,7 @@ pub fn bitmap(input: TokenStream) -> TokenStream {
 pub fn bitmap_attr(_args: TokenStream, input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as DeriveInput);
 
-    // Convert the attribute macro input to the existing BitmapInput format
+    // Converting the attribute macro input to the existing BitmapInput format
     let bitmap_input = convert_derive_to_bitmap_input(input);
 
     // Use the EXACT SAME expansion logic as the bitmap! macro
@@ -144,9 +144,9 @@ pub fn bitmap_attr(_args: TokenStream, input: TokenStream) -> TokenStream {
 }
 
 fn convert_derive_to_bitmap_input(input: DeriveInput) -> parser::BitmapInput {
-    let name = input.ident;  // Use 'name' not 'struct_name'
+    let name = input.ident;  
 
-    // Extract struct fields
+    // Extracting struct fields
     let syn::Data::Struct(data_struct) = input.data else {
         panic!("#[bitmap_attr] can only be used on structs");
     };
@@ -155,12 +155,12 @@ fn convert_derive_to_bitmap_input(input: DeriveInput) -> parser::BitmapInput {
         panic!("#[bitmap_attr] struct must have named fields");
     };
 
-    // Convert each field to the format expected by the existing parser
+    // Converting each field to the format expected by the existing parser
     let fields = fields_named.named.into_iter().map(|field| {
         let field_name = field.ident.expect("Field must have a name");
         let field_type = field.ty;
 
-        // Extract the size from the type (e.g., u1 -> 1, u7 -> 7)
+        // Extracting the size from the type (e.g., u1 -> 1, u7 -> 7)
         let type_str = field_type.to_token_stream().to_string();
 
         if !type_str.starts_with("u") {
@@ -180,7 +180,7 @@ fn convert_derive_to_bitmap_input(input: DeriveInput) -> parser::BitmapInput {
     }).collect();
 
     parser::BitmapInput {
-        name,  // Use 'name' not 'struct_name'
+        name,  
         fields,
     }
 }

tests/compare_macros.rs

@@ -1,4 +1,3 @@
-// tests/compare_macros.rs
 use bitmap::{bitmap, bitmap_attr};
 
 // Function-like macro (original)

tests/test_attr.rs

@@ -1,4 +1,3 @@
-// tests/test_attr.rs
 use bitmap::bitmap_attr;
 
 #[bitmap_attr]
@@ -11,15 +10,15 @@ struct TestBits {
 fn test_attribute_macro_creates_correct_api() {
     let mut bits = TestBits(0);
 
-    // Test that the macro generated the correct methods
+    // Testing that the macro generated the correct methods
     bits.set_flag(1);
     bits.set_counter(42);
 
     assert_eq!(bits.flag(), 1);
     assert_eq!(bits.counter(), 42);
 
-    // Test the raw value
-    assert_eq!(*bits, 0b10101010); // flag=1 (MSB), counter=42
+    // Testing the raw value
+    assert_eq!(*bits, 0b10101010); 
 
     println!("Attribute macro creates correct bitmap API!");
 }