A better way to return things

ewext/noita_api/src/lib.rs

@@ -1,10 +1,12 @@
+use std::num::NonZero;
+
 pub mod lua;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct EntityID(pub isize);
+pub struct EntityID(pub NonZero<isize>);
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct ComponentID(pub isize);
+pub struct ComponentID(pub NonZero<isize>);
 
 pub struct Obj(pub usize);
 
@@ -14,6 +16,7 @@ noita_api_macro::generate_components!();
 
 pub mod raw {
     use super::{Color, ComponentID, EntityID, Obj};
+    use crate::lua::LuaGetValue;
     use crate::lua::LuaPutValue;
     use std::borrow::Cow;
 
@@ -28,7 +31,7 @@ pub mod raw {
     ) -> eyre::Result<()> {
         let lua = LuaState::current()?;
         lua.get_global(c"ComponentGetValue2");
-        lua.push_integer(component.0);
+        lua.push_integer(component.0.into());
         lua.push_string(field);
         lua.call(2, expected_results);
         Ok(())

ewext/noita_api/src/lua.rs

@@ -207,13 +207,13 @@ impl LuaPutValue for str {
 
 impl LuaPutValue for EntityID {
     fn put(&self, lua: LuaState) {
-        self.0.put(lua);
+        isize::from(self.0).put(lua);
     }
 }
 
 impl LuaPutValue for ComponentID {
     fn put(&self, lua: LuaState) {
-        self.0.put(lua);
+        isize::from(self.0).put(lua);
     }
 }
 
@@ -244,3 +244,95 @@ impl<T: LuaPutValue> LuaPutValue for Option<T> {
         }
     }
 }
+
+/// Trait for arguments that can be retrieved from the lua stack.
+pub(crate) trait LuaGetValue {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self>
+    where
+        Self: Sized;
+    fn size() -> i32 {
+        1
+    }
+}
+
+impl LuaGetValue for i32 {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_integer(index) as Self)
+    }
+}
+
+impl LuaGetValue for isize {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_integer(index) as Self)
+    }
+}
+
+impl LuaGetValue for u32 {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(unsafe { mem::transmute(lua.to_integer(index) as i32) })
+    }
+}
+
+impl LuaGetValue for f32 {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_number(index) as f32)
+    }
+}
+
+impl LuaGetValue for f64 {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_number(index))
+    }
+}
+
+impl LuaGetValue for bool {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_bool(index))
+    }
+}
+
+impl LuaGetValue for Option<EntityID> {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        let ent = lua.to_integer(index);
+        Ok(if ent == 0 {
+            None
+        } else {
+            Some(EntityID(ent.try_into().unwrap()))
+        })
+    }
+}
+
+impl LuaGetValue for Option<ComponentID> {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        let com = lua.to_integer(index);
+        Ok(if com == 0 {
+            None
+        } else {
+            Some(ComponentID(com.try_into().unwrap()))
+        })
+    }
+}
+
+impl LuaGetValue for Cow<'static, str> {
+    fn get(lua: LuaState, index: i32) -> eyre::Result<Self> {
+        Ok(lua.to_string(index)?.into())
+    }
+}
+
+impl LuaGetValue for () {
+    fn get(_lua: LuaState, _index: i32) -> eyre::Result<Self> {
+        Ok(())
+    }
+}
+
+impl LuaGetValue for Obj {
+    fn get(_lua: LuaState, _index: i32) -> eyre::Result<Self> {
+        todo!()
+    }
+}
+
+impl LuaGetValue for Color {
+    fn get(_lua: LuaState, _index: i32) -> eyre::Result<Self> {
+        todo!()
+    }
+}

ewext/noita_api_macro/src/lib.rs

@@ -2,7 +2,6 @@ use std::ffi::CString;
 
 use heck::ToSnekCase;
 use proc_macro::TokenStream;
-use proc_macro2::Ident;
 use quote::{format_ident, quote};
 use serde::Deserialize;
 
@@ -89,35 +88,11 @@ impl Typ2 {
     fn as_rust_type_return(&self) -> proc_macro2::TokenStream {
         match self {
             Typ2::String => quote! {Cow<'static, str>},
+            Typ2::EntityID => quote! {Option<EntityID>},
+            Typ2::ComponentID => quote!(Option<ComponentID>),
             _ => self.as_rust_type(),
         }
     }
-
-    fn generate_lua_push(&self, arg_name: Ident) -> proc_macro2::TokenStream {
-        match self {
-            Typ2::Int => quote! {lua.push_integer(#arg_name as isize)},
-            Typ2::Number => quote! {lua.push_number(#arg_name)},
-            Typ2::String => quote! {lua.push_string(&#arg_name)},
-            Typ2::Bool => quote! {lua.push_bool(#arg_name)},
-            Typ2::EntityID => quote! {lua.push_integer(#arg_name.0 as isize)},
-            Typ2::ComponentID => quote! {lua.push_integer(#arg_name.0 as isize)},
-            Typ2::Obj => quote! { todo!() },
-            Typ2::Color => quote! { todo!() },
-        }
-    }
-
-    fn generate_lua_get(&self, index: i32) -> proc_macro2::TokenStream {
-        match self {
-            Typ2::Int => quote! {lua.to_integer(#index) as i32},
-            Typ2::Number => quote! {lua.to_number(#index)},
-            Typ2::String => quote! { lua.to_string(#index)?.into() },
-            Typ2::Bool => quote! {lua.to_bool(#index)},
-            Typ2::EntityID => quote! {EntityID(lua.to_integer(#index))},
-            Typ2::ComponentID => quote! {ComponentID(lua.to_integer(#index))},
-            Typ2::Obj => quote! { todo!() },
-            Typ2::Color => quote! { todo!() },
-        }
-    }
 }
 
 #[derive(Deserialize)]
@@ -260,14 +235,6 @@ fn generate_code_for_api_fn(api_fn: ApiFn) -> proc_macro2::TokenStream {
         // }
     };
 
-    let ret_expr = if api_fn.rets.is_empty() {
-        quote! { () }
-    } else {
-        // TODO support for more than one return value.
-        let ret = api_fn.rets.first().unwrap();
-        ret.typ.generate_lua_get(1)
-    };
-
     let fn_name_c = name_to_c_literal(api_fn.fn_name);
 
     let ret_count = api_fn.rets.len() as i32;
@@ -285,7 +252,7 @@ fn generate_code_for_api_fn(api_fn: ApiFn) -> proc_macro2::TokenStream {
 
             lua.call(last_non_empty+1, #ret_count);
 
-            let ret = Ok(#ret_expr);
+            let ret = LuaGetValue::get(lua, -1);
             lua.pop_last_n(#ret_count);
             ret
         }

ewext/src/lib.rs

@@ -6,7 +6,7 @@ use std::{
 };
 
 use addr_grabber::{grab_addrs, grabbed_fns, grabbed_globals};
-use eyre::bail;
+use eyre::{bail, OptionExt};
 
 use noita::{ntypes::Entity, pixel::NoitaPixelRun, ParticleWorldState};
 use noita_api::lua::{lua_bindings::lua_State, LuaState, ValuesOnStack, LUA};
@@ -95,7 +95,8 @@ fn bench_fn(_lua: LuaState) -> eyre::Result<()> {
     let start = Instant::now();
     let iters = 10000;
     for _ in 0..iters {
-        let player = noita_api::raw::entity_get_closest_with_tag(0.0, 0.0, "player_unit".into())?;
+        let player = noita_api::raw::entity_get_closest_with_tag(0.0, 0.0, "player_unit".into())?
+            .ok_or_eyre("Entity not found")?;
         noita_api::raw::entity_set_transform(player, 0.0, Some(0.0), None, None, None)?;
     }
     let elapsed = start.elapsed();
@@ -113,12 +114,12 @@ fn bench_fn(_lua: LuaState) -> eyre::Result<()> {
 }
 
 fn test_fn(_lua: LuaState) -> eyre::Result<()> {
-    let player = noita_api::raw::entity_get_closest_with_tag(0.0, 0.0, "player_unit".into())?;
+    let player = noita_api::raw::entity_get_closest_with_tag(0.0, 0.0, "player_unit".into())?
-    let damage_model = noita_api::DamageModelComponent(noita_api::raw::entity_get_first_component(
+        .ok_or_eyre("Entity not found")?;
-        player,
+    let damage_model = noita_api::DamageModelComponent(
-        "DamageModelComponent".into(),
+        noita_api::raw::entity_get_first_component(player, "DamageModelComponent".into(), None)?
-        None,
+            .ok_or_eyre("Could not find damage model")?,
-    )?);
+    );
     let hp = damage_model.hp()?;
 
     noita_api::raw::game_print(