Core Signatures

// lifecyclefn on_init(&self, ctx: &mut ScriptContext<'_, RT, RS, IP>)fn on_all_init(&self, ctx: &mut ScriptContext<'_, RT, RS, IP>)fn on_update(&self, ctx: &mut ScriptContext<'_, RT, RS, IP>)fn on_fixed_update(&self, ctx: &mut ScriptContext<'_, RT, RS, IP>)fn on_removal(&self, ctx: &mut ScriptContext<'_, RT, RS, IP>) // state / node accesswith_state!(ctx.run, StateType, node_id, |state| -> V { ... }) -> Vwith_state_mut!(ctx.run, StateType, node_id, |state| -> V { ... }) -> Option<V>with_node!(ctx.run, NodeType, node_id, |node| -> V { ... }) -> Vwith_node_mut!(ctx.run, NodeType, node_id, |node| -> V { ... }) -> Option<V>

Current Script Shape

Base script shape:

• single import: use perro_api::prelude::*;
• define SelfNodeType to declare which node type this script expects
• optional #[State] struct holding per-node instance data
• lifecycle! for frame/fixed/init/removal hooks
• methods! for reusable behavior functions

use perro_api::prelude::*; type SelfNodeType = Node2D; #[derive(Clone, Copy, Variant)]struct AimPoint {    target: Vector2,} impl Default for AimPoint {    fn default() -> Self {        Self {            target: Vector2::ZERO,        }    }} #[State]struct PlayerState {    #[default = 100]    health: i32,     #[default = 220.0]    speed: f32,     #[default = AimPoint::default()]    aim: AimPoint,} lifecycle!({    fn on_update(        &self,        ctx: &mut ScriptContext<'_, RT, RS, IP>,    ) {        let dt = delta_time!(ctx.run);        let right = key_down!(ctx.ipt, KeyCode::KeyD) as i32;        let left = key_down!(ctx.ipt, KeyCode::KeyA) as i32;        let jumped = key_pressed!(ctx.ipt, KeyCode::Space);        let axis = (right - left) as f32;         let speed = with_state!(ctx.run, PlayerState, ctx.id, |state| state.speed);         with_node_mut!(ctx.run, SelfNodeType, ctx.id, |node| {            node.position.x += axis * speed * dt;            if jumped {                node.position.y -= 24.0;            }        });         self.tick_health(ctx, -1);    }}); methods!({    fn tick_health(        &self,        ctx: &mut ScriptContext<'_, RT, RS, IP>,        delta: i32,    ) {        with_state_mut!(ctx.run, PlayerState, ctx.id, |state| {            state.health += delta;        });    }});

Still Rust

Perro does not turn scripts into a second language. A script file is Rust with a few engine entry points added on top. Use modules, structs, enums, traits, impl blocks, generics, helper functions, and crate dependencies from deps.toml like normal Rust code.

Registration happens when a scene assigns script = "res://path/file.rs". The Perro compiler finds that script, compiles the Rust module, wires its #[State], lifecycle!, and methods!, and uses Variant conversions for cross-script variables, method args, return values, and script_vars.