Edcode derive proc-macros for enum

crates/util/edcode-macros/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "rimecraft-edcode-macros"
+version = "0.1.0"
+edition = "2021"
+authors = ["C191239 <[email protected]>"]
+description = "Derive macros for rimecraft-edcode"
+repository = "https://github.com/rimecraft-rs/rimecraft/"
+license = "AGPL-3.0-or-later"
+categories = ["encoding"]
+
+[badges]
+maintenance = { status = "passively-maintained" }
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+syn = { version = "2.0" }
+quote = { version = "1.0" }
+
+[dev-dependencies]
+rimecraft-edcode = { path = "../edcode" }
+
+[lints]
+workspace = true
+
+[lib]
+proc-macro = true

crates/util/edcode-macros/src/lib.rs

@@ -0,0 +1,33 @@
+//! Proc-macros for deriving [`rimecraft_edcode`] traits.
+
+use proc_macro::TokenStream;
+use syn::{parse_macro_input, Data, DeriveInput};
+
+macro_rules! unsupported_error {
+    ($tr:literal, $ty:literal) => {
+        "deriving `$tr` to `$ty` is not supported"
+    };
+}
+
+/// Derive [`rimecraft_edcode::Encode`] to types.
+#[proc_macro_derive(Encode)]
+pub fn derive_encode(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    match input.data {
+        Data::Enum(data) => {
+            // TODO: derive `Encode` for `enum`.
+            todo!()
+        }
+        Data::Struct(data) => syn::Error::new(
+            data.struct_token.span,
+            unsupported_error!("Encode", "struct"),
+        )
+        .to_compile_error()
+        .into(),
+        Data::Union(data) => {
+            syn::Error::new(data.union_token.span, unsupported_error!("Encode", "union"))
+                .to_compile_error()
+                .into()
+        }
+    }
+}

crates/util/edcode/Cargo.toml

@@ -14,6 +14,7 @@ maintenance = { status = "passively-maintained" }
 [dependencies]
 bytes = "1.5"
 serde = { version = "1.0", optional = true }
+rimecraft-edcode-macros = { path = "../edcode-macros", optional = true }
 # custom formats
 fastnbt = { version = "2.4", optional = true }
 serde_json = { version = "1.0", optional = true }
@@ -24,6 +25,7 @@ glam = { version = "0.25", optional = true }
 [features]
 # default = ["serde", "nbt", "json", "uuid", "glam"]
 serde = ["dep:serde"]
+macros = ["dep:rimecraft-edcode-macros"]
 # custom formats
 fastnbt = ["serde", "dep:fastnbt"]
 json = ["serde", "dep:serde_json"]

crates/util/edcode/src/lib.rs

@@ -9,6 +9,9 @@ use std::io;
 
 pub use bytes;
 
+#[cfg(feature = "macros")]
+pub use rimecraft_edcode_macros::Encode;
+
 /// Describes types that can be encoded into a packet buffer.
 pub trait Encode {
     /// Encode into a buffer.