Game stats that reset every frame, inspired by immediate mode GUI.
gamedev
bevy
stats
Stated on rewriting basic struct derive.
Currently does not work as `darling` doesn't support "naked" attributes. Will need to implement manually.
+54
-34
+54
-34
immediate_stats_macros/src/lib.rs
+54
-34
immediate_stats_macros/src/lib.rs
···
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#[cfg(feature = "bevy_butler")]
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mod bevy_butler;
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+
use darling::FromField;
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use proc_macro_error::{
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emit_call_site_error, emit_call_site_warning, emit_warning, proc_macro_error,
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};
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use proc_macro2::{Span, TokenStream};
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use quote::{ToTokens, quote};
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use syn::{Data, DataEnum, DataStruct, DeriveInput, Field, Ident, Index, parse_macro_input};
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use syn::spanned::Spanned;
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use syn::{Data, DataEnum, DataStruct, DeriveInput, Field, Ident, Index, Type, parse_macro_input};
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#[proc_macro_derive(
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StatContainer,
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attributes(stat, stat_ignore, add_component, add_resource)
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-
)]
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#[proc_macro_derive(StatContainer, attributes(stat, stat_ignore, add_component))]
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#[proc_macro_error]
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pub fn stat_container_derive(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
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let tree: DeriveInput = parse_macro_input!(item as DeriveInput);
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let struct_name = &tree.ident;
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let method = match tree.data.clone() {
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Data::Struct(s) => stat_container_struct(s),
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let method_contents = match tree.data.clone() {
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Data::Struct(s) => struct_fields(s).unwrap(),
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Data::Enum(e) => stat_container_enum(e),
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Data::Union(_) => {
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emit_call_site_error!("This trait cannot be derived from unions.");
···
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}
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};
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-
let result = quote! {
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let method = quote! {
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impl StatContainer for #struct_name {
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#method
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fn reset_modifiers(&mut self) {
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#method_contents
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}
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}
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};
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···
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let systems = bevy_butler::register_systems(tree);
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match systems {
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Ok(systems) => quote! { #result #systems }.into(),
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Ok(systems) => quote! { #method #systems }.into(),
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Err(e) => e.write_errors().into(),
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}
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}
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#[cfg(not(feature = "bevy_butler"))]
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result.into()
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method.into()
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}
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fn stat_container_struct(s: DataStruct) -> TokenStream {
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match get_members_from_fields(s.fields) {
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MemberVec::Named(names) => {
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quote! {
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fn reset_modifiers(&mut self) {
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#(self.#names.reset_modifiers();)*
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}
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}
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}
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MemberVec::Unnamed(nums) => {
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quote! {
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fn reset_modifiers(&mut self) {
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#(self.#nums.reset_modifiers();)*
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}
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#[derive(FromField)] // Todo Implement manually to allow for naked attributes.
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#[darling(attributes(stat, stat_ignore))]
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struct FieldState {
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ident: Option<Ident>,
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ty: Type,
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#[darling(default, rename = "stat")]
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include: bool,
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#[darling(default, rename = "stat")]
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exclude: bool,
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}
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fn struct_fields(s: DataStruct) -> darling::Result<TokenStream> {
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let mut tokens = TokenStream::new();
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for (index, field) in s.fields.iter().enumerate() {
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let field_state = FieldState::from_field(&field)?;
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+
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let is_stat_type = field_state
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.ty
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.to_token_stream()
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.to_string()
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.contains("Stat");
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if (field_state.include || is_stat_type) && !field_state.exclude {
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if let Some(ident) = field_state.ident {
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tokens.extend(quote! {
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self.#ident.reset_modifiers();
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});
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} else {
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let index = Index::from(index);
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tokens.extend(quote! {
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self.#index.reset_modifiers();
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});
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}
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}
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MemberVec::None => {
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emit_call_site_warning!(
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"Unused derive. Consider adding `#[stat]` to a field that implements `StatContainer`."
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if field_state.include && field_state.exclude {
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emit_warning!(
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field.span(),
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"`stat` attribute is overruled by `stat_ignore` attribute."
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);
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TokenStream::new()
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}
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}
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Ok(tokens)
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}
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fn stat_container_enum(e: DataEnum) -> TokenStream {
···
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}
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quote! {
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fn reset_modifiers(&mut self) {
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match self {
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#(#cases)*
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_ => {},
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}
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match self {
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#(#cases)*
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_ => {},
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}
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}
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}