Game stats that reset every frame, inspired by immediate mode GUI.
gamedev
bevy
stats
Moved structs to sperate module.
Also renamed/added comments to make it less confusing.
+83
-73
+11
-73
immediate_stats_macros/src/lib.rs
+11
-73
immediate_stats_macros/src/lib.rs
···
1
-
use proc_macro2::{Ident, Span, TokenStream};
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+
mod stat_attributes;
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use crate::stat_attributes::{AttrType, Stat};
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use proc_macro2::{Ident, Span};
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use quote::quote;
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use std::collections::HashMap;
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use syn::{Data, DeriveInput};
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#[derive(Default)]
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struct Stat {
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base: Option<Ident>,
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bonus: Option<Ident>,
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multiplier: Option<Ident>,
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}
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impl Stat {
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fn set(&mut self, attr_type: AttrType, ident: Ident) {
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match attr_type {
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AttrType::Base => self.base = Some(ident),
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AttrType::Bonus => self.bonus = Some(ident),
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AttrType::Multiplier => self.multiplier = Some(ident),
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}
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}
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}
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impl Stat {
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/// Create the calculation for stat total.
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/// Results in `(self.base + self.bonus) * self.multiplier`
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/// with type conversions and missing values removed.
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/// # Panics
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/// When `self.base` is `None`.
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fn total_calculation(&self) -> TokenStream {
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let result = self.base.clone().expect("All stats require a base!");
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let mut result = quote! { self.#result };
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if let Some(bonus) = &self.bonus {
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result = quote! {
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#result + self.#bonus
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}
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}
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-
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if let Some(multiplier) = &self.multiplier {
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result = quote! {
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((#result) as f32 * self.#multiplier) as i32
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}
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}
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result
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}
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}
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enum AttrType {
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Base,
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Bonus,
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Multiplier,
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}
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impl TryFrom<&String> for AttrType {
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type Error = ();
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fn try_from(value: &String) -> Result<Self, Self::Error> {
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match value.as_str() {
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"base" => Ok(Self::Base),
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"bonus" => Ok(Self::Bonus),
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"multiplier" => Ok(Self::Multiplier),
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_ => Err(()),
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}
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}
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}
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impl TryFrom<&Ident> for AttrType {
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type Error = ();
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fn try_from(value: &Ident) -> Result<Self, Self::Error> {
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Self::try_from(&value.to_string())
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}
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}
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#[proc_macro_derive(StatContainer, attributes(base, bonus, multiplier))]
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pub fn stat_container_derive(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
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let tree: DeriveInput = syn::parse(item).expect("A valid TokenStream");
···
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match tree.data {
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Data::Struct(s) => {
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for field in s.fields {
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let ident = field.ident.unwrap();
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// (health_base, damage_base, etc.)
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let field_ident = field
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.ident
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.expect("Field must have an identifier. Cannot be used on tuples.");
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for attr in field.attrs {
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let path = attr.meta.path();
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// (base, bonus, or multiplier)
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let Ok(attr_ident) = path.require_ident() else {
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continue;
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};
···
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continue;
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};
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// (health, damage, etc.)
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let mut stat_ident = String::new();
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attr.parse_nested_meta(|meta| {
···
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}
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};
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stat.set(attr_type, ident.clone());
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stat.set(attr_type, field_ident.clone());
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}
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}
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}
+72
immediate_stats_macros/src/stat_attributes.rs
+72
immediate_stats_macros/src/stat_attributes.rs
···
1
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use proc_macro2::{Ident, TokenStream};
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use quote::quote;
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/// Stores the identifiers for the individual stat fields.
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#[derive(Default)]
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pub(super) struct Stat {
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pub base: Option<Ident>,
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pub bonus: Option<Ident>,
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pub multiplier: Option<Ident>,
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}
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+
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impl Stat {
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pub(super) fn set(&mut self, attr_type: AttrType, ident: Ident) {
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match attr_type {
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AttrType::Base => self.base = Some(ident),
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AttrType::Bonus => self.bonus = Some(ident),
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AttrType::Multiplier => self.multiplier = Some(ident),
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}
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}
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/// Create the calculation for stat total.
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/// Results in `(self.base + self.bonus) * self.multiplier`
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/// with type conversions and missing values removed.
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/// # Panics
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/// When `self.base` is `None`.
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pub(super) fn total_calculation(&self) -> TokenStream {
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let result = self.base.clone().expect("All stats require a base!");
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let mut result = quote! { self.#result };
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if let Some(bonus) = &self.bonus {
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result = quote! {
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#result + self.#bonus
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}
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}
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if let Some(multiplier) = &self.multiplier {
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result = quote! {
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((#result) as f32 * self.#multiplier) as i32
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}
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}
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result
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}
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}
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/// The types of stat fields.
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pub(super) enum AttrType {
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Base,
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Bonus,
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Multiplier,
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}
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impl TryFrom<&String> for AttrType {
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type Error = ();
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fn try_from(value: &String) -> Result<Self, Self::Error> {
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match value.as_str() {
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"base" => Ok(Self::Base),
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"bonus" => Ok(Self::Bonus),
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"multiplier" => Ok(Self::Multiplier),
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_ => Err(()),
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}
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}
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}
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impl TryFrom<&Ident> for AttrType {
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type Error = ();
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fn try_from(value: &Ident) -> Result<Self, Self::Error> {
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Self::try_from(&value.to_string())
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}
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}