introduce tags, structs, and reticles

this was meant to be split into smaller changes, but I realised I edited my existing revision too late.

crates/haku/src/value.rs

@@ -1,6 +1,6 @@
 use alloc::vec::Vec;
 
-use crate::{compiler::ClosureSpec, system::ChunkId};
+use crate::{bytecode::TagId, compiler::ClosureSpec, system::ChunkId};
 
 // TODO: Probably needs some pretty hardcore space optimization.
 // Maybe when we have static typing.
@@ -9,6 +9,7 @@ pub enum Value {
     Nil,
     False,
     True,
+    Tag(TagId),
     Number(f32),
     Vec4(Vec4),
     Rgba(Rgba),
@@ -73,6 +74,12 @@ pub struct Vec2 {
     pub y: f32,
 }
 
+impl Vec2 {
+    pub fn new(x: f32, y: f32) -> Self {
+        Self { x, y }
+    }
+}
+
 impl From<Vec4> for Vec2 {
     fn from(value: Vec4) -> Self {
         Self {
@@ -90,6 +97,17 @@ pub struct Vec4 {
     pub w: f32,
 }
 
+impl From<Vec2> for Vec4 {
+    fn from(value: Vec2) -> Self {
+        Self {
+            x: value.x,
+            y: value.y,
+            z: 0.0,
+            w: 0.0,
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, PartialOrd, Default)]
 #[repr(C)]
 pub struct Rgba {
@@ -123,6 +141,7 @@ pub enum Ref {
     List(List),
     Shape(Shape),
     Scribble(Scribble),
+    Reticle(Reticle),
 }
 
 impl Ref {
@@ -206,3 +225,8 @@ pub enum Scribble {
     Stroke(Stroke),
     Fill(Fill),
 }
+
+#[derive(Debug, Clone)]
+pub enum Reticle {
+    Dotter { draw: Value },
+}