add lists & VM memory limits

crates/haku/src/render.rs

@@ -71,12 +71,17 @@ impl<'a> Renderer<'a> {
         let (_id, scribble) = vm
             .get_ref_value(value)
             .ok_or_else(|| Self::create_exception(vm, value, NOT_A_SCRIBBLE))?;
-        let Ref::Scribble(scribble) = scribble else {
-            return Err(Self::create_exception(vm, value, NOT_A_SCRIBBLE));
-        };
 
-        match scribble {
-            Scribble::Stroke(stroke) => self.render_stroke(vm, value, stroke)?,
+        match &scribble {
+            Ref::List(list) => {
+                for element in &list.elements {
+                    self.render(vm, *element)?;
+                }
+            }
+            Ref::Scribble(scribble) => match scribble {
+                Scribble::Stroke(stroke) => self.render_stroke(vm, value, stroke)?,
+            },
+            _ => return Err(Self::create_exception(vm, value, NOT_A_SCRIBBLE))?,
         }
 
         Ok(())

crates/haku/src/system.rs

@@ -99,8 +99,10 @@ impl Display for ChunkError {
 impl Error for ChunkError {}
 
 pub mod fns {
+    use alloc::vec::Vec;
+
     use crate::{
-        value::{Ref, Rgba, Scribble, Shape, Stroke, Value, Vec4},
+        value::{List, Ref, Rgba, Scribble, Shape, Stroke, Value, Vec4},
         vm::{Exception, FnArgs, Vm},
     };
 
@@ -133,6 +135,8 @@ pub mod fns {
             0x88 ".b" => rgba_b,
             0x89 ".a" => rgba_a,
 
+            0x90 "list" => list,
+
             0xc0 "to-shape" => to_shape_f,
             0xc1 "line" => line,
             0xe0 "stroke" => stroke,
@@ -389,6 +393,13 @@ pub mod fns {
         Ok(Value::Number(rgba.r))
     }
 
+    pub fn list(vm: &mut Vm, args: FnArgs) -> Result<Value, Exception> {
+        let elements: Vec<_> = (0..args.num()).map(|i| args.get(vm, i)).collect();
+        vm.track_array(&elements)?;
+        let id = vm.create_ref(Ref::List(List { elements }))?;
+        Ok(Value::Ref(id))
+    }
+
     fn to_shape(value: Value, vm: &Vm) -> Option<Shape> {
         match value {
             Value::Nil | Value::False | Value::True | Value::Number(_) | Value::Rgba(_) => None,

crates/haku/src/value.rs

@@ -105,6 +105,7 @@ impl RefId {
 #[derive(Debug, Clone)]
 pub enum Ref {
     Closure(Closure),
+    List(List),
     Shape(Shape),
     Scribble(Scribble),
 }
@@ -143,6 +144,11 @@ pub struct Closure {
     pub captures: Vec<Value>,
 }
 
+#[derive(Debug, Clone, PartialEq)]
+pub struct List {
+    pub elements: Vec<Value>,
+}
+
 #[derive(Debug, Clone)]
 pub enum Shape {
     Point(Vec4),

crates/haku/src/vm.rs

@@ -17,6 +17,7 @@ pub struct VmLimits {
     pub call_stack_capacity: usize,
     pub ref_capacity: usize,
     pub fuel: usize,
+    pub memory: usize,
 }
 
 #[derive(Debug, Clone)]
@@ -26,6 +27,7 @@ pub struct Vm {
     refs: Vec<Ref>,
     defs: Vec<Value>,
     fuel: usize,
+    memory: usize,
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -33,6 +35,7 @@ pub struct VmImage {
     refs: usize,
     defs: usize,
     fuel: usize,
+    memory: usize,
 }
 
 #[derive(Debug, Clone)]
@@ -55,6 +58,7 @@ impl Vm {
             refs: Vec::with_capacity(limits.ref_capacity),
             defs: Vec::from_iter(iter::repeat(Value::Nil).take(defs.len() as usize)),
             fuel: limits.fuel,
+            memory: limits.memory,
         }
     }
 
@@ -75,6 +79,7 @@ impl Vm {
             refs: self.refs.len(),
             defs: self.defs.len(),
             fuel: self.fuel,
+            memory: self.memory,
         }
     }
 
@@ -398,6 +403,14 @@ impl Vm {
     pub fn create_exception(&self, message: &'static str) -> Exception {
         Exception { message }
     }
+
+    pub fn track_array<T>(&mut self, array: &[T]) -> Result<(), Exception> {
+        self.memory = self
+            .memory
+            .checked_sub(core::mem::size_of_val(array))
+            .ok_or_else(|| self.create_exception("out of heap memory"))?;
+        Ok(())
+    }
 }
 
 pub struct FnArgs {

crates/haku/tests/language.rs

@@ -44,6 +44,7 @@ fn eval(code: &str) -> Result<Value, Box<dyn Error>> {
         call_stack_capacity: 256,
         ref_capacity: 256,
         fuel: 32768,
+        memory: 1024,
     };
     let mut vm = Vm::new(defs, &limits);
     let chunk_id = system.add_chunk(chunk)?;