New nodes: Sort, Filter, Reverse, Shift, Shuffle, Number Sequence, List Indices, List Slice, Read Number (#4347)

Cargo.lock

@@ -2181,6 +2181,7 @@ dependencies = [
  "glam",
  "graphic-types",
  "node-macro",
+ "rand",
  "raster-types",
  "serde",
  "vector-types",

editor/src/messages/portfolio/document_migration.rs

@@ -108,7 +108,7 @@ const NODE_REPLACEMENTS: &[NodeReplacement<'static>] = &[
 			"graphene_core::transform_nodes::FreezeRealTimeNode",
 			"graphene_core::vector::SubpathSegmentLengthsNode",
 			"core_types::vector::SubpathSegmentLengthsNode",
-			// The deleted debug Option trio degrades to a passthrough of its single input (audit resolution 8)
+			// The deleted debug Option trio degrades to a passthrough of its single input
 			"graphene_core::ops::SizeOfNode",
 			"graphene_core::debug::SizeOfNode",
 			"graphene_core::ops::SomeNode",
@@ -2765,7 +2765,7 @@ fn migrate_removed_catalog_definitions(node_id: &NodeId, node: &DocumentNode, ne
 		}
 	}
 
-	// The removed Attach Attribute node (merged into Write Attribute per audit resolution 6) degrades to a passthrough of its
+	// The removed Attach Attribute node degrades to a passthrough of its
 	// content: its eager whole-list source input cannot be mechanically rewired as Write Attribute's lazy per-item value producer.
 	if let Some(DefinitionIdentifier::ProtoNode(identifier)) = document.network_interface.reference(node_id, network_path)
 		&& identifier.as_str().ends_with("::AttachAttributeNode")

node-graph/interpreted-executor/src/dynamic_executor/test.rs

@@ -346,6 +346,50 @@ fn position_value_converts_through_the_vector_input_adapter() {
 	assert!(result.is_some(), "The position should arrive as an Item<Vector> single-anchor path");
 }
 
+// A scalar wire feeding a `DVec2` connector splats into both axes through the input adapter's `Convert` row
+#[test]
+fn number_value_splats_through_the_vec2_input_adapter() {
+	let number_node = ProtoNode::value(ConstructionArgs::Value(TaggedValue::F64(-60.).into()), vec![NodeId(0)]);
+
+	let mut input_adapter_node = ProtoNode::value(ConstructionArgs::Nodes(vec![NodeId(0)]), vec![NodeId(1)]);
+	input_adapter_node.identifier = ProtoNodeIdentifier::new("input_adapter<DVec2>");
+
+	let network = ProtoNetwork {
+		inputs: vec![],
+		output: NodeId(1),
+		nodes: vec![(NodeId(0), number_node), (NodeId(1), input_adapter_node)],
+	};
+	let mut typing_context = TypingContext::new(&crate::node_registry::NODE_REGISTRY);
+	typing_context.update(&network).expect("An f64 wire should resolve the adapter's splat conversion row");
+	let tree = futures::executor::block_on(BorrowTree::new(network, &typing_context)).expect("The splat constructor should instantiate");
+
+	let context: Context = None;
+	let result: Option<Item<glam::DVec2>> = futures::executor::block_on(tree.eval(NodeId(1), context));
+	assert_eq!(result.map(|item| *item.element()), Some(glam::DVec2::splat(-60.)), "The scalar should splat into both axes");
+}
+
+// A scalar wire feeding a `String` connector formats as text through the input adapter's `Convert` row
+#[test]
+fn number_value_formats_through_the_string_input_adapter() {
+	let number_node = ProtoNode::value(ConstructionArgs::Value(TaggedValue::F64(42.).into()), vec![NodeId(0)]);
+
+	let mut input_adapter_node = ProtoNode::value(ConstructionArgs::Nodes(vec![NodeId(0)]), vec![NodeId(1)]);
+	input_adapter_node.identifier = ProtoNodeIdentifier::new("input_adapter<String>");
+
+	let network = ProtoNetwork {
+		inputs: vec![],
+		output: NodeId(1),
+		nodes: vec![(NodeId(0), number_node), (NodeId(1), input_adapter_node)],
+	};
+	let mut typing_context = TypingContext::new(&crate::node_registry::NODE_REGISTRY);
+	typing_context.update(&network).expect("An f64 wire should resolve the adapter's formatting conversion row");
+	let tree = futures::executor::block_on(BorrowTree::new(network, &typing_context)).expect("The formatting constructor should instantiate");
+
+	let context: Context = None;
+	let result: Option<Item<String>> = futures::executor::block_on(tree.eval(NodeId(1), context));
+	assert_eq!(result.map(|item| item.element().clone()), Some("42".to_string()), "The number should format as its text representation");
+}
+
 // A `List` wire feeding a `ListDyn` connector erases its element type through the input adapter's `Into` row
 #[test]
 fn list_wire_erases_through_the_list_dyn_input_adapter() {

node-graph/interpreted-executor/src/node_registry.rs

@@ -411,7 +411,10 @@ fn node_registry() -> HashMap<ProtoNodeIdentifier, HashMap<NodeIOTypes, NodeCons
 		Raster<CPU>,
 		Color,
 		Gradient,
+		f32,
 		f64,
+		u32,
+		u64,
 		bool,
 		String,
 		DVec2,
@@ -485,8 +488,8 @@ fn node_registry() -> HashMap<ProtoNodeIdentifier, HashMap<NodeIOTypes, NodeCons
 	node_types.extend(input_adapter_row!(from_element: String, element: BoxCorners));
 	// A number wire may feed the ranked `Item<BoxCorners>` connector, each number becoming a uniform radius for all four corners
 	node_types.extend(input_adapter_row!(from_element: f64, element: BoxCorners));
-	// Numeric wires cast between element types at a ranked connector, as `Convert` does for bare numeric wires
-	macro_rules! numeric_convert_node {
+	// The `Convert`-based counterpart of `input_adapter_row!`, for casts the std `Into` trait cannot express
+	macro_rules! convert_adapter_node {
 		(from_element: $from:ty, element: $element:ty) => {{
 			let entries: Vec<(ProtoNodeIdentifier, NodeConstructor, NodeIOTypes)> = vec![
 				input_adapter_row!(node: ConvertItemNode, from: Item<$from>, to: Item<$element>, element: $element),
@@ -495,19 +498,24 @@ fn node_registry() -> HashMap<ProtoNodeIdentifier, HashMap<NodeIOTypes, NodeCons
 			entries
 		}};
 	}
-	macro_rules! numeric_convert_star {
+	macro_rules! convert_adapter_wildcard {
 		(from: $from:ty, to: [$($to:ty),*]) => {{
 			let mut entries: Vec<(ProtoNodeIdentifier, NodeConstructor, NodeIOTypes)> = Vec::new();
-			$(entries.extend(numeric_convert_node!(from_element: $from, element: $to));)*
+			$(entries.extend(convert_adapter_node!(from_element: $from, element: $to));)*
 			entries
 		}};
 	}
-	node_types.extend(numeric_convert_star!(from: f64, to: [f32, u32, u64, i32, i64]));
-	node_types.extend(numeric_convert_star!(from: f32, to: [f64, u32, u64, i32, i64]));
-	node_types.extend(numeric_convert_star!(from: u32, to: [f64, f32, u64, i32, i64]));
-	node_types.extend(numeric_convert_star!(from: u64, to: [f64, f32, u32, i32, i64]));
-	node_types.extend(numeric_convert_star!(from: i32, to: [f64, f32, u32, u64, i64]));
-	node_types.extend(numeric_convert_star!(from: i64, to: [f64, f32, u32, u64, i32]));
+	// Numeric wires cast between numeric element types, splat to fill both axes of a `DVec2` connector, and format into a `String` connector
+	node_types.extend(convert_adapter_wildcard!(from: f64, to: [f32, u32, u64, i32, i64, DVec2, String]));
+	node_types.extend(convert_adapter_wildcard!(from: f32, to: [f64, u32, u64, i32, i64, DVec2, String]));
+	node_types.extend(convert_adapter_wildcard!(from: u32, to: [f64, f32, u64, i32, i64, DVec2, String]));
+	node_types.extend(convert_adapter_wildcard!(from: u64, to: [f64, f32, u32, i32, i64, DVec2, String]));
+	node_types.extend(convert_adapter_wildcard!(from: i32, to: [f64, f32, u32, u64, i64, DVec2, String]));
+	node_types.extend(convert_adapter_wildcard!(from: i64, to: [f64, f32, u32, u64, i32, DVec2, String]));
+	// Bool, position, and transform wires may feed a ranked `String` connector by formatting each element as text
+	node_types.extend(convert_adapter_node!(from_element: bool, element: String));
+	node_types.extend(convert_adapter_node!(from_element: DVec2, element: String));
+	node_types.extend(convert_adapter_node!(from_element: DAffine2, element: String));
 	// The sanctioned attribute value conversions: an Item wire's elements box per cell, while a List wire boxes whole as one value
 	macro_rules! attribute_value_node {
 		(Item<$element:ty>) => {

node-graph/libraries/core-types/src/ops.rs

@@ -45,6 +45,14 @@ pub trait Convert<T, C>: Sized {
 	fn convert(self, footprint: Footprint, converter: C) -> impl Future<Output = T> + Send;
 }
 
+impl<T: ToString + Send> Convert<String, ()> for T {
+	/// Converts this type into a `String` using its `ToString` implementation.
+	#[inline]
+	async fn convert(self, _: Footprint, _converter: ()) -> String {
+		self.to_string()
+	}
+}
+
 /// Constructs `Self` from a single anchor point at the given position. Implemented by the vector crate's
 /// path type so a position wire can convert to a single-point path without core-types depending on that crate.
 pub trait FromAnchorPosition {

node-graph/nodes/gcore/src/context.rs

@@ -46,6 +46,33 @@ fn read_gradient(ctx: impl Ctx + ExtractVarArgs) -> Item<Gradient> {
 	var_arg.downcast_ref().cloned().unwrap_or_default()
 }
 
+/// Reads the current number from within a **Map** node's loop.
+#[node_macro::node(category("Context"))]
+fn read_number(ctx: impl Ctx + ExtractVarArgs) -> Item<f64> {
+	let Ok(var_arg) = ctx.vararg(0) else { return Default::default() };
+	let var_arg = var_arg as &dyn std::any::Any;
+
+	if let Some(item) = var_arg.downcast_ref::<Item<f64>>() {
+		return item.clone();
+	}
+
+	// Numeric lists carry several possible element types, so probe each and widen to f64, keeping the item's attributes
+	if let Some(item) = var_arg.downcast_ref::<Item<f32>>() {
+		let (element, attributes) = item.clone().into_parts();
+		return Item::from_parts(element as f64, attributes);
+	}
+	if let Some(item) = var_arg.downcast_ref::<Item<u32>>() {
+		let (element, attributes) = item.clone().into_parts();
+		return Item::from_parts(element as f64, attributes);
+	}
+	if let Some(item) = var_arg.downcast_ref::<Item<u64>>() {
+		let (element, attributes) = item.clone().into_parts();
+		return Item::from_parts(element as f64, attributes);
+	}
+
+	Default::default()
+}
+
 #[node_macro::node(category("Context"), path(core_types::vector))]
 async fn read_position(
 	ctx: impl Ctx + ExtractPosition,

node-graph/nodes/graphic/Cargo.toml

@@ -17,3 +17,4 @@ dyn-any = { workspace = true }
 glam = { workspace = true }
 serde = { workspace = true }
 node-macro = { workspace = true }
+rand = { workspace = true }

node-graph/nodes/graphic/src/graphic.rs

@@ -1,11 +1,14 @@
 use core_types::bounds::{BoundingBox, RenderBoundingBox};
 use core_types::list::{AttributeValueDyn, Item, List, ListDyn, NodeIdPath};
-use core_types::registry::types::{Angle, SignedInteger};
+use core_types::registry::types::{Angle, SeedValue, SignedInteger};
 use core_types::{ATTR_EDITOR_LAYER_PATH, ATTR_EDITOR_MERGED_LAYERS, ATTR_TRANSFORM, AnyHash, BlendMode, CacheHash, CloneVarArgs, Color, Context, Ctx, ExtractAll, OwnedContextImpl};
 use glam::{DAffine2, DVec2};
 use graphic_types::graphic::{Graphic, IntoGraphicList};
 use graphic_types::{Artboard, Vector};
+use rand::SeedableRng;
+use rand::seq::SliceRandom;
 use raster_types::{CPU, GPU, Raster};
+use std::cmp::Ordering;
 use vector_types::gradient::{GradientSpreadMethod, GradientType};
 use vector_types::{Gradient, GradientStop, ReferencePoint};
 
@@ -45,12 +48,12 @@ pub fn remove_at_index<T: graphic_types::graphic::OmitIndex + Clone + Default>(
 	}
 }
 
-/// Returns the item at the specified index in a `List`, keeping its attributes.
+/// Returns the item at the specified index in a list, keeping its attributes.
 /// If no value exists at that index, the element type's default is returned.
 #[node_macro::node(category("General"), name("Item at Index"))]
 pub fn item_at_index<T: Clone + Default + Send + Sync + 'static>(
 	_: impl Ctx,
-	/// The `List` of data to take the item from.
+	/// The list of data to take the item from.
 	#[implementations(
 		List<String>,
 		List<bool>,
@@ -85,6 +88,328 @@ pub fn item_at_index<T: Clone + Default + Send + Sync + 'static>(
 	list.clone_item(resolved).unwrap_or_default()
 }
 
+/// Keeps chosen items from a list (those corresponding to `true` values) and discards the others (those corresponding to `false` values) based on the *Keep Pattern* bool list. A short pattern is repeated over the remainder of the filtered list, allowing a pattern like `[true, false]` to keep every other item starting from the first. An empty pattern keeps all items.
+#[node_macro::node(category("General"))]
+fn filter<T: Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list of data to filter.
+	#[implementations(
+		List<String>,
+		List<bool>,
+		List<f32>,
+		List<f64>,
+		List<u32>,
+		List<u64>,
+		List<DVec2>,
+		List<DAffine2>,
+		List<Vector>,
+		List<Graphic>,
+		List<Raster<CPU>>,
+		List<Raster<GPU>>,
+		List<Color>,
+		List<Gradient>,
+		List<Artboard>,
+	)]
+	list: List<T>,
+	/// The list of true and false values that determines which corresponding items are kept (`true`) and discarded (`false`). The pattern may repeat if it is shorter than the list of data.
+	keep_pattern: List<bool>,
+) -> List<T> {
+	// Tile the keep pattern over the items, so a short pattern repeats from the start
+	let pattern = keep_pattern.iter_element_values().as_slice();
+	if pattern.is_empty() {
+		return list;
+	}
+
+	list.into_iter().enumerate().filter_map(|(index, item)| pattern[index % pattern.len()].then_some(item)).collect()
+}
+
+/// Reverses the order of the items in a list, so the last item comes first and the first comes last.
+#[node_macro::node(category("General"))]
+fn reverse<T: Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list of data to reverse.
+	#[implementations(
+		List<String>,
+		List<bool>,
+		List<f32>,
+		List<f64>,
+		List<u32>,
+		List<u64>,
+		List<DVec2>,
+		List<DAffine2>,
+		List<Vector>,
+		List<Graphic>,
+		List<Raster<CPU>>,
+		List<Raster<GPU>>,
+		List<Color>,
+		List<Gradient>,
+		List<Artboard>,
+	)]
+	list: List<T>,
+) -> List<T> {
+	list.into_iter().rev().collect()
+}
+
+/// Shifts the items in a list by a number of positions. With wrapping, items pushed off one end reappear at the other. Otherwise they are dropped, shortening the list.
+#[node_macro::node(category("General"))]
+fn shift<T: Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list of data to shift.
+	#[implementations(
+		List<String>,
+		List<bool>,
+		List<f32>,
+		List<f64>,
+		List<u32>,
+		List<u64>,
+		List<DVec2>,
+		List<DAffine2>,
+		List<Vector>,
+		List<Graphic>,
+		List<Raster<CPU>>,
+		List<Raster<GPU>>,
+		List<Color>,
+		List<Gradient>,
+		List<Artboard>,
+	)]
+	list: List<T>,
+	/// How many positions to shift each item. Positive values shift items toward the start of the list, negative toward the end.
+	amount: Item<SignedInteger>,
+	/// Whether items shifted off one end wrap around to the other. When off, they are dropped and the list gets shorter.
+	#[default(true)]
+	wrap: Item<bool>,
+) -> List<T> {
+	let amount = amount.into_element() as i64;
+	let wrap = wrap.into_element();
+	let len = list.len() as i64;
+	if len == 0 {
+		return list;
+	}
+
+	let mut items: Vec<Item<T>> = list.into_iter().collect();
+	if wrap {
+		items.rotate_left((((amount % len) + len) % len) as usize);
+		items.into_iter().collect()
+	} else if amount >= 0 {
+		items.into_iter().skip(amount.min(len) as usize).collect()
+	} else {
+		items.into_iter().take((len + amount).max(0) as usize).collect()
+	}
+}
+
+/// Randomly reorders the items in a list. The same seed always produces the same ordering.
+#[node_macro::node(category("General"))]
+fn shuffle<T: Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list to have its items randomly reordered.
+	#[implementations(
+		List<String>,
+		List<bool>,
+		List<f32>,
+		List<f64>,
+		List<u32>,
+		List<u64>,
+		List<DVec2>,
+		List<DAffine2>,
+		List<Vector>,
+		List<Graphic>,
+		List<Raster<CPU>>,
+		List<Raster<GPU>>,
+		List<Color>,
+		List<Gradient>,
+		List<Artboard>,
+	)]
+	list: List<T>,
+	/// Seed to determine the unique variation of the random shuffle ordering. The same seed always produces the same ordering.
+	seed: Item<SeedValue>,
+) -> List<T> {
+	let seed = seed.into_element();
+	let mut items: Vec<Item<T>> = list.into_iter().collect();
+
+	let mut rng = rand::rngs::StdRng::seed_from_u64(seed.into());
+	items.shuffle(&mut rng);
+
+	items.into_iter().collect()
+}
+
+/// Generates a list of evenly spaced numbers, starting at a value and progressing by a step (which may be positive, negative, or zero) for a given count.
+#[node_macro::node(category("General"), name("Number Sequence"))]
+fn number_sequence(
+	_: impl Ctx,
+	_primary: (),
+	/// The first number in the sequence.
+	start: Item<f64>,
+	/// The amount added to reach each successive number.
+	#[default(1.)]
+	step: Item<f64>,
+	/// How many numbers to generate.
+	#[default(10)]
+	count: Item<u32>,
+) -> List<f64> {
+	let (start, step, count) = (*start.element(), *step.element(), count.into_element());
+
+	(0..count).map(|i| Item::new_from_element(start + step * i as f64)).collect()
+}
+
+/// Counts out the index of each item in a list (0, 1, 2, and so on), producing a list of numbers with one for each item.
+#[node_macro::node(category("General"))]
+fn list_indices(
+	_: impl Ctx,
+	/// The list whose items are counted.
+	list: ListDyn,
+	/// The number that the count begins from for the first item.
+	start_index: Item<SignedInteger>,
+) -> List<f64> {
+	let start_index = start_index.into_element();
+
+	(0..list.len()).map(|index| Item::new_from_element(start_index + index as f64)).collect()
+}
+
+/// Extracts a portion of a list, starting at "Start" and ending before "End".
+///
+/// Negative indices count from the end of the list. If the index of "Start" equals or exceeds "End", the result is an empty list.
+#[node_macro::node(category("General"))]
+fn list_slice<T: Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list of data to take a portion of.
+	#[implementations(
+		List<String>,
+		List<bool>,
+		List<f32>,
+		List<f64>,
+		List<u32>,
+		List<u64>,
+		List<DVec2>,
+		List<DAffine2>,
+		List<Vector>,
+		List<Graphic>,
+		List<Raster<CPU>>,
+		List<Raster<GPU>>,
+		List<Color>,
+		List<Gradient>,
+		List<Artboard>,
+	)]
+	list: List<T>,
+	/// The index of the first item in the portion. Negative indices count from the end of the list.
+	start: Item<SignedInteger>,
+	/// The index the portion ends before, which is not included. Zero or negative indices count from the end of the list.
+	end: Item<SignedInteger>,
+) -> List<T> {
+	let (start, end) = (start.into_element(), end.into_element());
+	let total_items = list.len();
+
+	let start = if start < 0. {
+		total_items.saturating_sub(start.abs() as usize)
+	} else {
+		(start as usize).min(total_items)
+	};
+	let end = if end <= 0. {
+		total_items.saturating_sub(end.abs() as usize)
+	} else {
+		(end as usize).min(total_items)
+	};
+
+	if start >= end {
+		return List::new();
+	}
+
+	list.into_iter().skip(start).take(end - start).collect()
+}
+
+/// Pairwise ordering used by the Sort node for element values. Types without a natural
+/// order compare as equal, so the stable sort leaves their items in their original relative positions.
+pub trait ElementOrder {
+	fn element_order(&self, _other: &Self) -> Ordering {
+		Ordering::Equal
+	}
+}
+impl ElementOrder for String {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.cmp(other)
+	}
+}
+impl ElementOrder for bool {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.cmp(other)
+	}
+}
+impl ElementOrder for f32 {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.total_cmp(other)
+	}
+}
+impl ElementOrder for f64 {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.total_cmp(other)
+	}
+}
+impl ElementOrder for u32 {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.cmp(other)
+	}
+}
+impl ElementOrder for u64 {
+	fn element_order(&self, other: &Self) -> Ordering {
+		self.cmp(other)
+	}
+}
+impl ElementOrder for DVec2 {}
+impl ElementOrder for DAffine2 {}
+impl ElementOrder for Vector {}
+impl ElementOrder for Graphic {}
+impl ElementOrder for Raster<CPU> {}
+impl ElementOrder for Raster<GPU> {}
+impl ElementOrder for Color {}
+impl ElementOrder for Gradient {}
+impl ElementOrder for Artboard {}
+
+/// Reorders a list's items from smallest to largest, either by each item's own value or by a parallel list of sortable values in the *Sort Order* input. The sort is stable, so items with the same sort order retain their relative positions.
+#[node_macro::node(category("General"))]
+fn sort<T: ElementOrder + Clone + Send + Sync + 'static, U: ElementOrder + Send + Sync + 'static>(
+	_: impl Ctx,
+	/// The list of data to reorder.
+	#[implementations(
+		List<String>, List<bool>, List<f32>, List<f64>, List<u32>, List<u64>, List<DVec2>, List<DAffine2>, List<Vector>, List<Graphic>, List<Raster<CPU>>, List<Raster<GPU>>, List<Color>, List<Gradient>, List<Artboard>,
+		List<String>, List<bool>, List<f32>, List<f64>, List<u32>, List<u64>, List<DVec2>, List<DAffine2>, List<Vector>, List<Graphic>, List<Raster<CPU>>, List<Raster<GPU>>, List<Color>, List<Gradient>, List<Artboard>,
+		List<String>, List<bool>, List<f32>, List<f64>, List<u32>, List<u64>, List<DVec2>, List<DAffine2>, List<Vector>, List<Graphic>, List<Raster<CPU>>, List<Raster<GPU>>, List<Color>, List<Gradient>, List<Artboard>,
+	)]
+	list: List<T>,
+	/// The optional list of orderable values, corresponding item-to-item with the input list, to sort by instead of the items' own values.
+	#[expose]
+	#[implementations(
+		List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>, List<f64>,
+		List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>, List<String>,
+		List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>, List<bool>,
+	)]
+	sort_order: List<U>,
+	/// Reverses the sorted list order, following descending order instead of ascending (numbers largest-to-smallest, strings Z-to-A, etc.).
+	reverse: Item<bool>,
+) -> List<T> {
+	let reverse = reverse.into_element();
+
+	// Order by the parallel keys when provided (repeating the last if there are fewer keys than items), otherwise by the element values themselves
+	let keys = sort_order.iter_element_values().as_slice();
+	let elements: Vec<&T> = list.iter_element_values().collect();
+
+	let mut order: Vec<usize> = (0..list.len()).collect();
+	order.sort_by(|&a, &b| {
+		let ordering = match keys {
+			[] => elements[a].element_order(elements[b]),
+			keys => keys[a.min(keys.len() - 1)].element_order(&keys[b.min(keys.len() - 1)]),
+		};
+		if reverse { ordering.reverse() } else { ordering }
+	});
+
+	let mut result = List::new();
+	for index in order {
+		if let Some(item) = list.clone_item(index) {
+			result.push(item);
+		}
+	}
+
+	result
+}
+
 #[node_macro::node(category("General"))]
 async fn map<Item: AnyHash + Send + Sync + CacheHash>(
 	ctx: impl Ctx + CloneVarArgs + ExtractAll,
@@ -215,8 +540,8 @@ pub fn path_of_subgraph(_: impl Ctx, node_path: Item<NodeIdPath>) -> Item<NodeId
 	Item::new_from_element(NodeIdPath(node_path.into_iter().take(len.saturating_sub(1)).collect()))
 }
 
-/// Sets a named attribute on the input `List`, computing one value per item via the value-producing input. That input
-/// is evaluated once per item, with the item's index and the item itself (as a `List` containing only that item,
+/// Sets a named attribute on the input list, computing one value per item via the value-producing input. That input
+/// is evaluated once per item, with the item's index and the item itself (as a list containing only that item,
 /// passed as a vararg) provided via context, so the upstream pipeline can return a different value per item that may
 /// be derived from the item's own data. If the attribute already exists, its values are replaced; if not, it's added.
 /// The value is type-erased into an `Item<AttributeValueDyn>` by the auto-inserted input adapter, so this node only
@@ -224,7 +549,7 @@ pub fn path_of_subgraph(_: impl Ctx, node_path: Item<NodeIdPath>) -> Item<NodeId
 #[node_macro::node(category("Attributes: Write"))]
 async fn write_attribute<T: AnyHash + Clone + Send + Sync + CacheHash>(
 	ctx: impl ExtractAll + CloneVarArgs + Ctx,
-	/// The `List` to set the named attribute on (one value per item).
+	/// The list to set the named attribute on (one value per item).
 	#[implementations(
 		List<String>,
 		List<bool>,
@@ -473,11 +798,11 @@ fn read_attribute_raster(
 	result
 }
 
-/// Joins two `List`s of the same type, extending the base `List` with the items from the new `List`.
+/// Joins two lists of the same type, extending the base list with the items from the new list.
 #[node_macro::node(category("General"))]
 pub async fn extend<T: 'n + Send + Clone>(
 	_: impl Ctx,
-	/// The `List` whose items will appear at the start of the extended `List`.
+	/// The list whose items will appear at the start of the extended list.
 	#[implementations(
 		List<String>,
 		List<bool>,
@@ -496,7 +821,7 @@ pub async fn extend<T: 'n + Send + Clone>(
 		List<Artboard>,
 	)]
 	base: List<T>,
-	/// The `List` whose items will appear at the end of the extended `List`.
+	/// The list whose items will appear at the end of the extended list.
 	#[expose]
 	#[implementations(
 		List<String>,
@@ -724,3 +1049,128 @@ fn colors_to_gradient<T: IntoGraphicList>(_: impl Ctx, #[implementations(List<Gr
 	});
 	Item::new_from_element(Gradient::new(colors))
 }
+
+#[cfg(test)]
+mod test {
+	use super::*;
+
+	fn list_of<T>(elements: impl IntoIterator<Item = T>) -> List<T> {
+		elements.into_iter().map(Item::new_from_element).collect()
+	}
+
+	fn elements<T: Clone>(list: &List<T>) -> Vec<T> {
+		list.iter_element_values().cloned().collect()
+	}
+
+	#[test]
+	fn sorts_elements_by_their_natural_order() {
+		let list = list_of(["banana".to_string(), "apple".to_string(), "cherry".to_string()]);
+		let sorted = sort((), list, List::<f64>::new(), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), ["apple", "banana", "cherry"]);
+	}
+
+	#[test]
+	fn sorts_elements_in_reverse() {
+		let list = list_of([3., 1., 2.]);
+		let sorted = sort((), list, List::<f64>::new(), Item::new_from_element(true));
+		assert_eq!(elements(&sorted), [3., 2., 1.]);
+	}
+
+	#[test]
+	fn sort_order_keys_override_element_order() {
+		let list = list_of(["apple".to_string(), "banana".to_string(), "cherry".to_string()]);
+		let sorted = sort((), list, list_of([2., 0., 1.]), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), ["banana", "cherry", "apple"]);
+	}
+
+	#[test]
+	fn short_sort_order_repeats_its_last_key() {
+		let list = list_of(["a".to_string(), "b".to_string(), "c".to_string()]);
+		let sorted = sort((), list, list_of([2., 1.]), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), ["b", "c", "a"]);
+	}
+
+	#[test]
+	fn long_sort_order_ignores_its_extra_keys() {
+		let list = list_of([1., 2.]);
+		let sorted = sort((), list, list_of([3., 1., 0., 5.]), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), [2., 1.]);
+	}
+
+	#[test]
+	fn text_sort_order_keys_order_items_alphabetically() {
+		let list = list_of([1., 2., 3.]);
+		let sorted = sort((), list, list_of(["c".to_string(), "a".to_string(), "b".to_string()]), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), [2., 3., 1.]);
+	}
+
+	#[test]
+	fn unsortable_elements_keep_their_original_order() {
+		let list = list_of([DVec2::new(3., 3.), DVec2::new(1., 1.), DVec2::new(2., 2.)]);
+		let sorted = sort((), list, List::<f64>::new(), Item::new_from_element(false));
+		assert_eq!(elements(&sorted), [DVec2::new(3., 3.), DVec2::new(1., 1.), DVec2::new(2., 2.)]);
+	}
+
+	#[test]
+	fn shift_wraps_items_around() {
+		let forward = shift((), list_of([1., 2., 3., 4.]), Item::new_from_element(1.), Item::new_from_element(true));
+		assert_eq!(elements(&forward), [2., 3., 4., 1.]);
+
+		let backward = shift((), list_of([1., 2., 3., 4.]), Item::new_from_element(-1.), Item::new_from_element(true));
+		assert_eq!(elements(&backward), [4., 1., 2., 3.]);
+	}
+
+	#[test]
+	fn shift_without_wrapping_drops_items() {
+		let dropped_front = shift((), list_of([1., 2., 3., 4.]), Item::new_from_element(1.), Item::new_from_element(false));
+		assert_eq!(elements(&dropped_front), [2., 3., 4.]);
+
+		let dropped_back = shift((), list_of([1., 2., 3., 4.]), Item::new_from_element(-1.), Item::new_from_element(false));
+		assert_eq!(elements(&dropped_back), [1., 2., 3.]);
+	}
+
+	#[test]
+	fn shuffle_is_deterministic_and_preserves_elements() {
+		let original = [1., 2., 3., 4., 5., 6., 7., 8.];
+		let first = shuffle((), list_of(original), Item::new_from_element(42_u32));
+		let second = shuffle((), list_of(original), Item::new_from_element(42_u32));
+		assert_eq!(elements(&first), elements(&second), "the same seed should always produce the same ordering");
+
+		let mut recovered = elements(&first);
+		recovered.sort_by(|a, b| a.partial_cmp(b).unwrap());
+		assert_eq!(recovered, original, "shuffling should preserve all the elements");
+	}
+
+	#[test]
+	fn number_sequence_generates_evenly_spaced_numbers() {
+		let sequence = number_sequence((), (), Item::new_from_element(0.), Item::new_from_element(2.), Item::new_from_element(4_u32));
+		assert_eq!(elements(&sequence), [0., 2., 4., 6.]);
+	}
+
+	#[test]
+	fn list_indices_counts_each_item() {
+		let indices = list_indices((), ListDyn::from(list_of(["a".to_string(), "b".to_string(), "c".to_string()])), Item::new_from_element(0.));
+		assert_eq!(elements(&indices), [0., 1., 2.]);
+
+		let from_one = list_indices((), ListDyn::from(list_of(["a".to_string(), "b".to_string(), "c".to_string()])), Item::new_from_element(1.));
+		assert_eq!(elements(&from_one), [1., 2., 3.]);
+	}
+
+	#[test]
+	fn list_slice_takes_the_portion_between_start_and_end() {
+		let portion = list_slice((), list_of([1., 2., 3., 4., 5.]), Item::new_from_element(1.), Item::new_from_element(3.));
+		assert_eq!(elements(&portion), [2., 3.]);
+	}
+
+	#[test]
+	fn list_slice_resolves_negative_indices_from_the_end() {
+		let portion = list_slice((), list_of([1., 2., 3., 4., 5.]), Item::new_from_element(-2.), Item::new_from_element(0.));
+		assert_eq!(elements(&portion), [4., 5.], "an end of zero reaches through the end of the list");
+	}
+
+	#[test]
+	fn list_slice_yields_nothing_when_start_reaches_end() {
+		let portion = list_slice((), list_of([1., 2., 3., 4., 5.]), Item::new_from_element(3.), Item::new_from_element(3.));
+		assert!(elements(&portion).is_empty());
+	}
+}