Merge pull request 'Closures, Higher-Order Functions, and Everything in Between' (#44) from kym-captures into main

Reviewed-on: #44

debug/app.ona

@@ -1,29 +1,18 @@
 
-let printer = lambda ():
+let test_param = "monkey wrench"
+
+let printer = lambda (pfx):
+	@print(test_param)
+
 	return lambda (msg):
-		@print("This is a func call")
+		@print(pfx)
 		@print(msg)
 	end
 end
 
-let pr = printer()
+let pr = printer("this is a final closure")
-var i = 0
 
-pr("test")
+pr("goodbye")
-
-while i < 5:
-	pr("hello, world")
-
-	i = i + 1
-end
-
-if i > 6:
-	pr("`i` greater than `6`")
-elif i == 4:
-	pr("`i` is equal to `4`")
-else:
-	pr("i'unno")
-end
 
 return {
 	.title = "Game",

source/coral/utf8.zig

@@ -196,6 +196,8 @@ pub const HexadecimalFormat = struct {
 		_ = self;
 		_ = writer;
 		_ = value;
+
+		unreachable;
 	}
 };
 

source/ona/app.zig

@@ -21,7 +21,7 @@ pub const Manifest = struct {
 			if (try kym.get_field(env, manifest, "width")) |ref| {
 				defer env.discard(ref);
 
-				const fixed = try env.unbox_fixed(ref);
+				const fixed = try env.unwrap_fixed(ref);
 
 				if (fixed > 0 and fixed < coral.math.max_int(@typeInfo(@TypeOf(self.width)).Int)) {
 					break: get @intCast(fixed);
@@ -35,7 +35,7 @@ pub const Manifest = struct {
 			if (try kym.get_field(env, manifest, "height")) |ref| {
 				defer env.discard(ref);
 
-				const fixed = try env.unbox_fixed(ref);
+				const fixed = try env.unwrap_fixed(ref);
 
 				if (fixed > 0 and fixed < coral.math.max_int(@typeInfo(@TypeOf(self.height)).Int)) {
 					break: get @intCast(fixed);
@@ -49,7 +49,7 @@ pub const Manifest = struct {
 			if (try kym.get_field(env, manifest, "tick_rate")) |ref| {
 				defer env.discard(ref);
 
-				break: get @floatCast(try env.unbox_float(ref));
+				break: get @floatCast(try env.unwrap_float(ref));
 			}
 
 			break: get self.tick_rate;
@@ -58,7 +58,7 @@ pub const Manifest = struct {
 		if (try kym.get_field(env, manifest, "title")) |ref| {
 			defer env.discard(ref);
 
-			const title_string = try env.unbox_string(ref);
+			const title_string = try env.unwrap_string(ref);
 			const limited_title_len = @min(title_string.len, self.title.len);
 
 			coral.io.copy(&self.title, title_string[0 .. limited_title_len]);

source/ona/file.zig

@@ -11,9 +11,9 @@ pub const Access = union (enum) {
 			.null => return null,
 
 			.sandboxed_path => |sandboxed_path| {
-				const readable_path_string = sandboxed_path.joined(readable_path).to_string() orelse return null;
+				const path_string = sandboxed_path.joined(readable_path).get_string();
 
-				return @ptrCast(ext.SDL_RWFromFile(readable_path_string.ptr, "rb"));
+				return @ptrCast(ext.SDL_RWFromFile(path_string.ptr, "rb"));
 			},
 		}
 	}
@@ -23,7 +23,7 @@ pub const Access = union (enum) {
 			.null => return null,
 
 			.sandboxed_path => |sandboxed_path| {
-				const path_string = sandboxed_path.joined(path).to_string() orelse return null;
+				const path_string = sandboxed_path.joined(path).get_string();
 				const rw_ops = ext.SDL_RWFromFile(path_string, "rb") orelse return null;
 				const file_size = ext.SDL_RWseek(rw_ops, 0, ext.RW_SEEK_END);
 
@@ -96,12 +96,8 @@ pub const Path = extern struct {
 		return path;
 	}
 
-	pub fn to_string(self: Path) ?[:0]const coral.io.Byte {
+	pub fn get_string(self: Path) [:0]const coral.io.Byte {
-		const last_index = self.data.len - 1;
+		coral.debug.assert(self.data[self.data.len - 1] == 0);
-
-		if (self.data[last_index] != 0) {
-			return null;
-		}
 
 		return coral.io.slice_sentineled(@as(coral.io.Byte, 0), @as([*:0]const coral.io.Byte, @ptrCast(&self.data)));
 	}

source/ona/kym.zig

@@ -2,10 +2,6 @@ const Chunk = @import("./kym/Chunk.zig");
 
 const Table = @import("./kym/Table.zig");
 
-const app = @import("./app.zig");
-
-const builtin = @import("builtin");
-
 const coral = @import("coral");
 
 const file = @import("./file.zig");
@@ -15,7 +11,7 @@ const tokens = @import("./kym/tokens.zig");
 const tree = @import("./kym/tree.zig");
 
 pub const Frame = struct {
-	name: []const coral.io.Byte = "",
+	name_stringable: *RuntimeRef,
 	arg_count: u8,
 	locals_top: usize,
 
@@ -23,8 +19,8 @@ pub const Frame = struct {
 		return env.locals.values[self.locals_top .. (self.locals_top + self.arg_count)];
 	}
 
-	pub fn get_arg(self: *const Frame, env: *RuntimeEnv, arg_index: u8) RuntimeError!*const RuntimeRef {
+	pub fn expect_arg(self: *const Frame, env: *RuntimeEnv, arg_index: u8) RuntimeError!*const RuntimeRef {
-		return self.has_arg(env, arg_index) orelse env.raise(error.BadOperation, "nil reference");
+		return self.has_arg(env, arg_index) orelse env.raise(error.TypeMismatch, "nil reference", .{});
 	}
 
 	pub fn has_arg(self: *const Frame, env: *RuntimeEnv, arg_index: u8) ?*const RuntimeRef {
@@ -69,16 +65,24 @@ pub const RuntimeEnv = struct {
 				},
 
 				.float => |rhs_float| self.new_float(@as(Float, @floatFromInt(lhs_fixed)) + rhs_float),
-				else => self.raise(error.TypeMismatch, "right-hand object is not addable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not addable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
 			.float => |lhs_float| switch (rhs.object().payload) {
 				.float => |rhs_float| self.new_float(lhs_float + rhs_float),
 				.fixed => |rhs_fixed| self.new_float(lhs_float + @as(Float, @floatFromInt(rhs_fixed))),
-				else => self.raise(error.TypeMismatch, "right-hand object is not addable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not addable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
-			else => self.raise(error.TypeMismatch, "left-hand object is not addable"),
+			else => self.raise(error.TypeMismatch, "left-hand {typename} is not addable", .{
+				.typename = lhs.typename(),
+			}),
 		};
 	}
 
@@ -88,18 +92,18 @@ pub const RuntimeEnv = struct {
 			try self.locals.push_one(try self.acquire(arg));
 		}
 
-		const frame = try self.push_frame(args.len);
+		const frame = try self.push_frame(callable, args.len);
 
 		defer self.pop_frame();
 
-		return self.call_frame(callable, frame);
+		return self.call_frame(frame);
 	}
 
 	pub fn call_frame(self: *RuntimeEnv, callable: *const RuntimeRef, frame: Frame) RuntimeError!?*RuntimeRef {
 		return switch (callable.object().payload) {
 			.syscall => |syscall| syscall(self, frame),
 			.dynamic => |dynamic| dynamic.typeinfo().call(self, dynamic.userdata(), frame),
-			else => self.raise(error.TypeMismatch, "object is not callable"),
+			else => self.raise(error.TypeMismatch, "{typename} is not callable", .{.typename = callable.typename()}),
 		};
 	}
 
@@ -108,16 +112,24 @@ pub const RuntimeEnv = struct {
 			.fixed => |lhs_fixed| switch (rhs.object().payload) {
 				.fixed => |rhs_fixed| @as(Float, @floatFromInt(lhs_fixed)) - @as(Float, @floatFromInt(rhs_fixed)),
 				.float => |rhs_float| @as(Float, @floatFromInt(lhs_fixed)) - rhs_float,
-				else => return self.raise(error.TypeMismatch, "right-hand object is not comparable"),
+
+				else => return self.raise(error.TypeMismatch, "right-hand {typename} is not comparable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
 			.float => |lhs_float| switch (rhs.object().payload) {
 				.float => |rhs_float| lhs_float - rhs_float,
 				.fixed => |rhs_fixed| lhs_float - @as(Float, @floatFromInt(rhs_fixed)),
-				else => return self.raise(error.TypeMismatch, "right-hand object is not comparable"),
+
+				else => return self.raise(error.TypeMismatch, "right-hand {typename} is not comparable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
-			else => return self.raise(error.TypeMismatch, "left-hand object is not comparable"),
+			else => return self.raise(error.TypeMismatch, "left-hand {typename} is not comparable", .{
+				.typename = lhs.typename(),
+			}),
 		};
 	}
 
@@ -132,6 +144,12 @@ pub const RuntimeEnv = struct {
 			switch (object.payload) {
 				.false, .true, .float, .fixed, .symbol, .vector2, .vector3, .syscall => {},
 
+				.boxed => |*boxed| {
+					if (boxed.*) |boxed_value| {
+						self.discard(boxed_value);
+					}
+				},
+
 				.string => |string| {
 					coral.debug.assert(string.len >= 0);
 					self.allocator.deallocate(string.ptr[0 .. @intCast(string.len)]);
@@ -155,21 +173,29 @@ pub const RuntimeEnv = struct {
 			.fixed => |lhs_fixed| switch (rhs.object().payload) {
 				.fixed => |rhs_fixed| self.new_float(@as(Float, @floatFromInt(lhs_fixed)) / @as(Float, @floatFromInt(rhs_fixed))),
 				.float => |rhs_float| self.new_float(@as(Float, @floatFromInt(lhs_fixed)) / rhs_float),
-				else => self.raise(error.TypeMismatch, "right-hand object is not divisible"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not divisible", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
 			.float => |lhs_float| switch (rhs.object().payload) {
 				.float => |rhs_float| self.new_float(lhs_float / rhs_float),
 				.fixed => |rhs_fixed| self.new_float(lhs_float / @as(Float, @floatFromInt(rhs_fixed))),
-				else => self.raise(error.TypeMismatch, "right-hand object is not divisible"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not divisible", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
-			else => self.raise(error.TypeMismatch, "left-hand object is not divisible"),
+			else => self.raise(error.TypeMismatch, "left-hand {typename} is not divisible", .{
+				.typename = lhs.typename(),
+			}),
 		};
 	}
 
 	pub fn expect(self: *RuntimeEnv, value: ?*RuntimeRef) RuntimeError!*RuntimeRef {
-		return value orelse self.raise(error.TypeMismatch, "nil reference");
+		return value orelse self.raise(error.TypeMismatch, "nil reference", .{});
 	}
 
 	pub fn free(self: *RuntimeEnv) void {
@@ -194,16 +220,8 @@ pub const RuntimeEnv = struct {
 
 	pub fn get(self: *RuntimeEnv, indexable: *RuntimeRef, index: *const RuntimeRef) RuntimeError!?*RuntimeRef {
 		return switch (indexable.object().payload) {
-			.false => self.raise(error.TypeMismatch, "false is not get-indexable"),
-			.true => self.raise(error.TypeMismatch, "true is not get-indexable"),
-			.fixed => self.raise(error.TypeMismatch, "fixed is not get-indexable"),
-			.float => self.raise(error.TypeMismatch, "float is not get-indexable"),
-			.string => self.raise(error.TypeMismatch, "string is not get-indexable"),
-			.symbol => self.raise(error.TypeMismatch, "symbol is not get-indexable"),
-			.syscall => self.raise(error.TypeMismatch, "syscall is not get-indexable"),
-
 			.vector2 => |vector2| swizzle: {
-				const swizzle_symbol = try self.unbox_symbol(index);
+				const swizzle_symbol = try self.unwrap_symbol(index);
 				var swizzle_buffer = [_]f32{0} ** 3;
 				var swizzle_count = @as(usize, 0);
 
@@ -228,7 +246,7 @@ pub const RuntimeEnv = struct {
 			},
 
 			.vector3 => |vector3| swizzle: {
-				const swizzle_symbol = try self.unbox_symbol(index);
+				const swizzle_symbol = try self.unwrap_symbol(index);
 				var swizzle_buffer = [_]f32{0} ** 3;
 				var swizzle_count = @as(usize, 0);
 
@@ -254,14 +272,22 @@ pub const RuntimeEnv = struct {
 			},
 
 			.dynamic => |dynamic| dynamic.typeinfo().get(self, dynamic.userdata(), index),
+
+			else => self.raise(error.TypeMismatch, "{typename} is not get-indexable", .{
+				.typename = indexable.typename(),
+			}),
 		};
 	}
 
 	pub fn import(self: *RuntimeEnv, file_path: file.Path) RuntimeError!?*RuntimeRef {
+		const file_name = file_path.get_string();
+
 		var chunk = make_chunk: {
 			const file_data =
 				(try file.allocate_and_load(self.allocator, self.options.import_access, file_path)) orelse {
-					return self.raise(error.BadOperation, "failed to open or read file specified");
+					return self.raise(error.BadOperation, "failed to open or read `{name}`", .{
+						.name = file_name,
+					});
 				};
 
 			defer self.allocator.deallocate(file_data);
@@ -282,24 +308,21 @@ pub const RuntimeEnv = struct {
 				};
 			}
 
-			break: make_chunk try Chunk.make(self, file_path.to_string() orelse "<script>", &root.environment);
+			const chunk_name = try self.new_string(file_name);
+
+			defer self.discard(chunk_name);
+
+			break: make_chunk try Chunk.make(self, chunk_name, &root.environment);
 		};
 
-		if (builtin.mode == .Debug) {
-			const string_ref = try chunk.dump(self);
-
-			defer self.discard(string_ref);
-
-			const string = string_ref.as_string();
-
-			coral.debug.assert(string != null);
-			app.log_info(string.?);
-		}
-
 		defer chunk.free(self);
 
 		return execute_chunk: {
-			const frame = try self.push_frame(0);
+			const name = try self.new_string(file_name);
+
+			defer self.discard(name);
+
+			const frame = try self.push_frame(name, 0);
 
 			defer self.pop_frame();
 
@@ -329,16 +352,24 @@ pub const RuntimeEnv = struct {
 				},
 
 				.float => |rhs_float| self.new_float(@as(Float, @floatFromInt(lhs_fixed)) * rhs_float),
-				else => self.raise(error.TypeMismatch, "right-hand object is not multiplicable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not multiplicable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
 			.float => |lhs_float| switch (rhs.object().payload) {
 				.float => |rhs_float| self.new_float(lhs_float * rhs_float),
 				.fixed => |rhs_fixed| self.new_float(lhs_float * @as(Float, @floatFromInt(rhs_fixed))),
-				else => self.raise(error.TypeMismatch, "right-hand object is not multiplicable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not multiplicable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
-			else => self.raise(error.TypeMismatch, "left-hand object is not multiplicable"),
+			else => self.raise(error.TypeMismatch, "left-hand {typename} is not multiplicable", .{
+				.typename = lhs.typename(),
+			}),
 		};
 	}
 
@@ -346,7 +377,7 @@ pub const RuntimeEnv = struct {
 		return switch (value.object().payload) {
 			.fixed => |fixed| self.new_fixed(-fixed),
 			.float => |float| self.new_float(-float),
-			else => self.raise(error.TypeMismatch, "object is not negatable"),
+			else => self.raise(error.TypeMismatch, "{typename} is not negatable", .{.typename = value.typename()}),
 		};
 	}
 
@@ -357,11 +388,20 @@ pub const RuntimeEnv = struct {
 		});
 	}
 
+	pub fn new_boxed(self: *RuntimeEnv, value: ?*const RuntimeRef) RuntimeError!*RuntimeRef {
+		return RuntimeRef.allocate(self.allocator, .{
+			.ref_count = 1,
+			.payload = .{.boxed = if (value) |ref| ref.acquire() else null},
+		});
+	}
+
 	pub fn new_dynamic(
 		self: *RuntimeEnv,
-		userdata: [*]const coral.io.Byte,
+		userdata: []const coral.io.Byte,
 		typeinfo: *const Typeinfo,
 	) RuntimeError!*RuntimeRef {
+		coral.debug.assert(userdata.len == typeinfo.size);
+
 		const dynamic = try self.allocator.reallocate(null, @sizeOf(usize) + typeinfo.size);
 
 		errdefer self.allocator.deallocate(dynamic);
@@ -440,7 +480,7 @@ pub const RuntimeEnv = struct {
 
 		errdefer table.free(self);
 
-		return try self.new_dynamic(coral.io.bytes_of(&table).ptr, Table.typeinfo);
+		return try self.new_dynamic(coral.io.bytes_of(&table), Table.typeinfo);
 	}
 
 	pub fn new_vector2(self: *RuntimeEnv, x: f32, y: f32) RuntimeError!*RuntimeRef {
@@ -470,23 +510,33 @@ pub const RuntimeEnv = struct {
 	}
 
 	pub fn pop_frame(self: *RuntimeEnv) void {
-		var to_pop = self.locals.values.len - (self.frames.pop() orelse unreachable).locals_top;
+		const popped_frame = self.frames.pop();
 
-		while (to_pop != 0) {
+		coral.debug.assert(popped_frame != null);
-			if (self.locals.pop() orelse unreachable) |local| {
+		self.discard(popped_frame.?.name_stringable);
+
+		var locals_to_pop = self.locals.values.len - popped_frame.?.locals_top;
+
+		while (locals_to_pop != 0) {
+			const popped_local = self.locals.pop();
+
+			coral.debug.assert(popped_local != null);
+
+			if (popped_local.?) |local| {
 				self.discard(local);
 			}
 
-			to_pop -= 1;
+			locals_to_pop -= 1;
 		}
 	}
 
 	pub fn pop_local(self: *RuntimeEnv) RuntimeError!?*RuntimeRef {
-		return self.locals.pop() orelse self.raise(error.IllegalState, "stack underflow");
+		return self.locals.pop() orelse self.raise(error.IllegalState, "stack underflow", .{});
 	}
 
-	pub fn push_frame(self: *RuntimeEnv, arg_count: u8) RuntimeError!Frame {
+	pub fn push_frame(self: *RuntimeEnv, name_stringable: *RuntimeRef, arg_count: u8) RuntimeError!Frame {
 		const frame = Frame{
+			.name_stringable = name_stringable.acquire(),
 			.arg_count = arg_count,
 			.locals_top = self.locals.values.len - arg_count,
 		};
@@ -496,8 +546,14 @@ pub const RuntimeEnv = struct {
 		return frame;
 	}
 
-	pub fn raise(self: *RuntimeEnv, error_value: RuntimeError, message: []const coral.io.Byte) RuntimeError {
+	pub fn raise(self: *RuntimeEnv, error_value: RuntimeError, comptime format: []const coral.io.Byte, args: anytype) RuntimeError {
-		self.print_error(message);
+		{
+			const formatted_message = try coral.utf8.alloc_formatted(self.allocator, format, args);
+
+			defer self.allocator.deallocate(formatted_message);
+
+			self.print_error(formatted_message);
+		}
 
 		if (!self.frames.is_empty()) {
 			self.print_error("stack trace:");
@@ -507,7 +563,17 @@ pub const RuntimeEnv = struct {
 			while (remaining_frames != 0) {
 				remaining_frames -= 1;
 
-				self.print_error(self.frames.values[remaining_frames].name);
+				const callable_string = try self.to_string(self.frames.values[remaining_frames].name_stringable);
+
+				defer self.discard(callable_string);
+
+				self.print_error(get_name: {
+					const string = callable_string.as_string();
+
+					coral.debug.assert(string != null);
+
+					break: get_name string.?;
+				});
 			}
 		}
 
@@ -517,7 +583,10 @@ pub const RuntimeEnv = struct {
 	pub fn set(self: *RuntimeEnv, indexable: *RuntimeRef, index: *const RuntimeRef, value: ?*const RuntimeRef) RuntimeError!void {
 		return switch (indexable.object().payload) {
 			.dynamic => |dynamic| dynamic.typeinfo().set(self, dynamic.userdata(), index, value),
-			else => self.raise(error.TypeMismatch, "object is not set-indexable"),
+
+			else => self.raise(error.TypeMismatch, "{typename} is not set-indexable", .{
+				.typename = indexable.typename(),
+			}),
 		};
 	}
 
@@ -533,16 +602,24 @@ pub const RuntimeEnv = struct {
 				},
 
 				.float => |rhs_float| self.new_float(@as(Float, @floatFromInt(lhs_fixed)) - rhs_float),
-				else => self.raise(error.TypeMismatch, "right-hand object is not subtractable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not subtractable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
 			.float => |lhs_float| switch (rhs.object().payload) {
 				.float => |rhs_float| self.new_float(lhs_float - rhs_float),
 				.fixed => |rhs_fixed| self.new_float(lhs_float - @as(Float, @floatFromInt(rhs_fixed))),
-				else => self.raise(error.TypeMismatch, "right-hand object is not subtractable"),
+
+				else => self.raise(error.TypeMismatch, "right-hand {typename} is not subtractable", .{
+					.typename = rhs.typename(),
+				}),
 			},
 
-			else => self.raise(error.TypeMismatch, "left-hand object is not subtractable"),
+			else => self.raise(error.TypeMismatch, "left-hand {typename} is not subtractable", .{
+				.typename = lhs.typename(),
+			}),
 		};
 	}
 
@@ -573,6 +650,7 @@ pub const RuntimeEnv = struct {
 				break: convert self.new_string(string[0 .. length.?]);
 			},
 
+			.boxed => |boxed| if (boxed) |boxed_value| self.to_string(boxed_value) else self.new_string("nil"),
 			.symbol => |symbol| self.new_string(coral.io.slice_sentineled(@as(coral.io.Byte, 0), symbol)),
 			.string => value.acquire(),
 
@@ -580,7 +658,7 @@ pub const RuntimeEnv = struct {
 				var string = [_:0]coral.io.Byte{0} ** 64;
 				var buffer = coral.io.FixedBuffer{.bytes = &string};
 
-				const length = coral.utf8.print_formatted(buffer.as_writer(), "vec3({x}, {y})", .{
+				const length = coral.utf8.print_formatted(buffer.as_writer(), "@vec2({x}, {y})", .{
 					.x = vector2[0],
 					.y = vector2[1],
 				});
@@ -594,7 +672,7 @@ pub const RuntimeEnv = struct {
 				var string = [_:0]coral.io.Byte{0} ** 96;
 				var buffer = coral.io.FixedBuffer{.bytes = &string};
 
-				const length = coral.utf8.print_formatted(buffer.as_writer(), "vec3({x}, {y}, {z})", .{
+				const length = coral.utf8.print_formatted(buffer.as_writer(), "@vec3({x}, {y}, {z})", .{
 					.x = vector3[0],
 					.y = vector3[1],
 					.z = vector3[2],
@@ -610,34 +688,36 @@ pub const RuntimeEnv = struct {
 		};
 	}
 
-	pub fn unbox_dynamic(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![]coral.io.Byte {
+	pub fn unwrap_dynamic(self: *RuntimeEnv, value: *const RuntimeRef, typeinfo: *const Typeinfo) RuntimeError![]coral.io.Byte {
-		return switch (value.object().payload) {
+		return value.as_dynamic(typeinfo) orelse self.raise(error.TypeMismatch, "expected dynamic object, not {typename}", .{
-			.dynamic => |dynamic| dynamic.userdata(),
+			.typename = value.typename(),
-			else => self.raise(error.TypeMismatch, "expected fixed object")
+		});
-		};
 	}
 
-	pub fn unbox_float(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError!Float {
+	pub fn unwrap_float(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError!Float {
 		return switch (value.object().payload) {
 			.fixed => |fixed| @floatFromInt(fixed),
 			.float => |float| float,
-			else => self.raise(error.TypeMismatch, "expected float object")
+			else => self.raise(error.TypeMismatch, "expected float, not {typename}", .{.typename = value.typename()}),
 		};
 	}
 
-	pub fn unbox_fixed(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError!Fixed {
+	pub fn unwrap_fixed(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError!Fixed {
-		return value.as_fixed() orelse self.raise(error.TypeMismatch, "expected fixed object");
+		return value.as_fixed() orelse self.raise(error.TypeMismatch, "expected fixed, not {typename}", .{
+			.typename = value.typename(),
+		});
 	}
 
-	pub fn unbox_string(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![]const coral.io.Byte {
+	pub fn unwrap_string(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![]const coral.io.Byte {
-		return value.as_string() orelse self.raise(error.TypeMismatch, "expected string object");
+		return value.as_string() orelse self.raise(error.TypeMismatch, "expected string, not {typename}", .{
+			.typename = value.typename(),
+		});
 	}
 
-	pub fn unbox_symbol(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![*:0]const coral.io.Byte {
+	pub fn unwrap_symbol(self: *RuntimeEnv, value: *const RuntimeRef) RuntimeError![*:0]const coral.io.Byte {
-		return switch (value.object().payload) {
+		return value.as_symbol() orelse self.raise(error.TypeMismatch, "expected symbol, not {typename}", .{
-			.symbol => |symbol| symbol,
+			.typename = value.typename(),
-			else => self.raise(error.TypeMismatch, "expected symbol object")
+		});
-		};
 	}
 };
 
@@ -661,6 +741,7 @@ pub const RuntimeRef = opaque {
 			vector2: [2]f32,
 			vector3: [3]f32,
 			syscall: *const Syscall,
+			boxed: ?*RuntimeRef,
 
 			string: struct {
 				ptr: [*]coral.io.Byte,
@@ -712,9 +793,23 @@ pub const RuntimeRef = opaque {
 		return @ptrCast(try coral.io.allocate_one(allocator, data));
 	}
 
+	pub fn as_boxed(self: *const RuntimeRef) ?*?*RuntimeRef {
+		return switch (self.object().payload) {
+			.boxed => |*boxed| boxed,
+			else => null,
+		};
+	}
+
+	pub fn as_dynamic(self: *const RuntimeRef, typeinfo: *const Typeinfo) ?[]u8 {
+		return switch (self.object().payload) {
+			.dynamic => |dynamic| if (dynamic.typeinfo() == typeinfo) dynamic.userdata() else null,
+			else => null,
+		};
+	}
+
 	pub fn as_fixed(self: *const RuntimeRef) ?Fixed {
 		return switch (self.object().payload) {
-			.fixed => |fixed| @intCast(@as(u32, @bitCast(fixed))),
+			.fixed => |fixed| fixed,
 			else => null,
 		};
 	}
@@ -727,6 +822,14 @@ pub const RuntimeRef = opaque {
 				break: get string.ptr[0 .. @intCast(string.len)];
 			},
 
+			.symbol => |symbol| coral.io.slice_sentineled(@as(u8, 0), symbol),
+			else => null,
+		};
+	}
+
+	pub fn as_symbol(self: *const RuntimeRef) ?[*:0]const coral.io.Byte {
+		return switch (self.object().payload) {
+			.symbol => |symbol| symbol,
 			else => null,
 		};
 	}
@@ -757,6 +860,18 @@ pub const RuntimeRef = opaque {
 				else => false,
 			},
 
+			.boxed => |boxed| unbox: {
+				if (boxed) |boxed_value| {
+					break: unbox boxed_value.equals(other);
+				}
+
+				if (other.as_boxed()) |boxed_value| {
+					break: unbox boxed_value.* == null;
+				}
+
+				break: unbox false;
+			},
+
 			.vector2 => |self_vector| switch (other.object().payload) {
 				.vector2 => |other_vector| coral.io.are_equal(coral.io.bytes_of(&self_vector), coral.io.bytes_of(&other_vector)),
 				else => false,
@@ -797,6 +912,7 @@ pub const RuntimeRef = opaque {
 			.vector2 => |vector| @bitCast(vector),
 			.vector3 => |vector| coral.io.jenkins_hash(@typeInfo(usize).Int, coral.io.bytes_of(&vector)),
 			.syscall => |syscall| @intFromPtr(syscall),
+			.boxed => |boxed| @intFromPtr(boxed),
 			.string => |string| coral.io.djb2_hash(@typeInfo(usize).Int, string.unpack()),
 			.dynamic => |dynamic| @intFromPtr(dynamic.typeinfo()) ^ @intFromPtr(dynamic.userdata().ptr),
 		};
@@ -812,6 +928,7 @@ pub const RuntimeRef = opaque {
 			.vector2 => |vector| coral.io.all_equals(coral.io.bytes_of(&vector), 0),
 			.vector3 => |vector| coral.io.all_equals(coral.io.bytes_of(&vector), 0),
 			.syscall => true,
+			.boxed => |boxed| boxed != null,
 			.string => |string| string.len != 0,
 			.dynamic => true,
 		};
@@ -827,6 +944,7 @@ pub const RuntimeRef = opaque {
 			.vector2 => "vector2",
 			.vector3 => "vector3",
 			.syscall => "syscall",
+			.boxed => "boxed",
 			.string => "string",
 			.dynamic => "dynamic",
 		};
@@ -844,18 +962,24 @@ pub const Typeinfo = struct {
 	set: *const fn (env: *RuntimeEnv, userdata: []coral.io.Byte, value: *const RuntimeRef, value: ?*const RuntimeRef) RuntimeError!void = default_set,
 
 	fn default_call(env: *RuntimeEnv, _: []coral.io.Byte, _: Frame) RuntimeError!?*RuntimeRef {
-		return env.raise(error.BadOperation, "object is not callable");
+		return env.raise(error.BadOperation, "this dynamic object is not callable", .{});
 	}
 
 	fn default_get(env: *RuntimeEnv, _: []coral.io.Byte, _: *const RuntimeRef) RuntimeError!?*RuntimeRef {
-		return env.raise(error.BadOperation, "object is not get-indexable");
+		return env.raise(error.BadOperation, "this dynamic object is not get-indexable", .{});
 	}
 
 	fn default_set(env: *RuntimeEnv, _: []coral.io.Byte, _: *const RuntimeRef, _: ?*const RuntimeRef) RuntimeError!void {
-		return env.raise(error.BadOperation, "object is not set-indexable");
+		return env.raise(error.BadOperation, "this dynamic object is not set-indexable", .{});
 	}
 };
 
+pub fn assert(env: *RuntimeEnv, condition: bool) RuntimeError!void {
+	if (!condition) {
+		return env.raise(error.IllegalState, "assertion", .{});
+	}
+}
+
 pub fn get_field(env: *RuntimeEnv, indexable: *RuntimeRef, field: []const coral.io.Byte) RuntimeError!?*RuntimeRef {
 	const field_symbol = try env.new_symbol(field);
 

source/ona/kym/Chunk.zig

@@ -1,5 +1,9 @@
+const app = @import("../app.zig");
+
 const Compiler = @import("./Compiler.zig");
 
+const builtin = @import("builtin");
+
 const coral = @import("coral");
 
 const file = @import("../file.zig");
@@ -12,6 +16,7 @@ name: *kym.RuntimeRef,
 arity: u8,
 opcodes: OpcodeList,
 constants: ConstList,
+bindings: []?*kym.RuntimeRef,
 
 const Builtin = enum {
 	import,
@@ -23,6 +28,7 @@ const Builtin = enum {
 const ConstList = coral.list.Stack(*kym.RuntimeRef);
 
 const OpcodeList = coral.list.Stack(union (enum) {
+	ret,
 	pop,
 	push_nil,
 	push_true,
@@ -32,13 +38,15 @@ const OpcodeList = coral.list.Stack(union (enum) {
 	push_top,
 	push_table: u32,
 	push_builtin: Builtin,
-	push_closure: u8,
+	push_binding: u8,
-	push_self,
 	push_boxed,
 	set_local: u8,
 	get_dynamic,
 	set_dynamic,
+	get_box,
+	set_box,
 	call: u8,
+	bind: u8,
 
 	not,
 	neg,
@@ -67,23 +75,21 @@ pub fn dump(chunk: Self, env: *kym.RuntimeEnv) kym.RuntimeError!*kym.RuntimeRef
 	defer buffer.free();
 
 	const writer = coral.list.stack_as_writer(&buffer);
-	_ = coral.utf8.print_string(writer, coral.io.slice_sentineled(@as(coral.io.Byte, 0), try env.unbox_symbol(chunk.name)));
 
-	_ = coral.utf8.print_string(writer, ":\n");
+	_ = coral.utf8.print_string(writer, "\n");
 
 	while (opcode_cursor < chunk.opcodes.values.len) : (opcode_cursor += 1) {
 		_ = coral.utf8.print_formatted(writer, "[{instruction}]: ", .{.instruction = opcode_cursor});
 
 		_ = switch (chunk.opcodes.values[opcode_cursor]) {
+			.ret => coral.utf8.print_string(writer, "ret\n"),
 			.pop => coral.utf8.print_string(writer, "pop\n"),
 			.push_nil => coral.utf8.print_string(writer, "push nil\n"),
 			.push_true => coral.utf8.print_string(writer, "push true\n"),
 			.push_false => coral.utf8.print_string(writer, "push false\n"),
 
 			.push_const => |push_const| print: {
-				if (push_const >= chunk.constants.values.len) {
+				try kym.assert(env, push_const < chunk.constants.values.len);
-					return env.raise(error.IllegalState, "invalid constant");
-				}
 
 				const string_ref = try env.to_string(chunk.constants.values[push_const]);
 
@@ -107,10 +113,9 @@ pub fn dump(chunk: Self, env: *kym.RuntimeEnv) kym.RuntimeError!*kym.RuntimeRef
 			}),
 
 			.push_boxed => coral.utf8.print_string(writer, "push boxed\n"),
-			.push_self => coral.utf8.print_string(writer, "push self\n"),
 
-			.push_closure => |push_closure| coral.utf8.print_formatted(writer, "push closure <{count}>\n", .{
+			.push_binding => |push_binding| coral.utf8.print_formatted(writer, "push binding <{binding}>\n", .{
-				.count = push_closure,
+				.binding = push_binding,
 			}),
 
 			.push_builtin => |push_builtin| coral.utf8.print_formatted(writer, "push builtin <{builtin}>\n", .{
@@ -122,7 +127,16 @@ pub fn dump(chunk: Self, env: *kym.RuntimeEnv) kym.RuntimeError!*kym.RuntimeRef
 				},
 			}),
 
-			.set_local => |local_set| coral.utf8.print_formatted(writer, "set local <{local}>\n", .{.local = local_set}),
+			.bind => |bind| coral.utf8.print_formatted(writer, "bind <{count}>\n", .{
+				.count = bind,
+			}),
+
+			.set_local => |local_set| coral.utf8.print_formatted(writer, "set local <{local}>\n", .{
+				.local = local_set,
+			}),
+
+			.get_box => coral.utf8.print_string(writer, "get box\n"),
+			.set_box => coral.utf8.print_string(writer, "set box\n"),
 			.get_dynamic => coral.utf8.print_string(writer, "get dynamic\n"),
 			.set_dynamic => coral.utf8.print_string(writer, "set dynamic\n"),
 			.call => |call| coral.utf8.print_formatted(writer, "call <{count}>\n", .{.count = call}),
@@ -145,11 +159,13 @@ pub fn dump(chunk: Self, env: *kym.RuntimeEnv) kym.RuntimeError!*kym.RuntimeRef
 	return env.new_string(buffer.values);
 }
 
-pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
+pub fn execute(self: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
 	var opcode_cursor = @as(u32, 0);
 
-	while (opcode_cursor < chunk.opcodes.values.len) : (opcode_cursor += 1) {
+	while (opcode_cursor < self.opcodes.values.len) : (opcode_cursor += 1) {
-		switch (chunk.opcodes.values[opcode_cursor]) {
+		switch (self.opcodes.values[opcode_cursor]) {
+			.ret => break,
+
 			.pop => {
 				if (try env.pop_local()) |ref| {
 					env.discard(ref);
@@ -161,17 +177,12 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 			.push_false => try env.locals.push_one(try env.new_boolean(false)),
 
 			.push_const => |push_const| {
-				if (push_const >= chunk.constants.values.len) {
+				try kym.assert(env, push_const < self.constants.values.len);
-					return env.raise(error.IllegalState, "invalid constant");
+				try env.locals.push_one(self.constants.values[push_const].acquire());
-				}
-
-				try env.locals.push_one(chunk.constants.values[push_const].acquire());
 			},
 
 			.push_local => |push_local| {
-				if (push_local >= env.locals.values.len) {
+				try kym.assert(env, push_local < (env.locals.values.len - frame.locals_top));
-					return env.raise(error.IllegalState, "invalid local");
-				}
 
 				if (env.locals.values[frame.locals_top + push_local]) |local| {
 					try env.locals.push_one(local.acquire());
@@ -183,9 +194,7 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 			.push_top => {
 				const frame_locals = env.locals.values[frame.locals_top ..];
 
-				if (frame_locals.len == 0) {
+				try kym.assert(env, frame_locals.len != 0);
-					return env.raise(error.IllegalState, "stack overflow");
-				}
 
 				if (frame_locals[frame_locals.len - 1]) |local| {
 					try env.locals.push_one(local.acquire());
@@ -219,19 +228,54 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 			},
 
 			.push_boxed => {
-				// TODO: Implement.
+				const value = try env.pop_local();
-				unreachable;
+
+				defer {
+					if (value) |ref| {
+						env.discard(ref);
+					}
+				}
+
+				const boxable = try env.new_boxed(value);
+
+				errdefer env.discard(boxable);
+
+				try env.locals.push_one(boxable);
 			},
 
-			.push_self => {
+			.push_binding => |push_binding| {
-				// TODO: Implement.
+				try kym.assert(env, push_binding <= self.bindings.len);
-				unreachable;
+				try env.locals.push_one(if (self.bindings[push_binding]) |value| value.acquire() else null);
 			},
 
-			.push_closure => |push_closure| {
+			.bind => |bind| {
-				// TODO: Implement.
+				const callable = try env.expect(try env.pop_local());
-				_ = push_closure;
+
-				unreachable;
+				errdefer env.discard(callable);
+
+				const chunk = @as(*Self, @ptrCast(@alignCast(try env.unwrap_dynamic(callable, typeinfo))));
+
+				chunk.bindings = try coral.io.allocate_many(env.allocator, bind, @as(?*kym.RuntimeRef, null));
+
+				for (0 .. bind) |index| {
+					const value = try env.pop_local();
+
+					errdefer {
+						if (value) |ref| {
+							env.discard(ref);
+						}
+					}
+
+					const binding = &chunk.bindings[index];
+
+					if (binding.*) |*existing_binding| {
+						env.discard(existing_binding.*);
+					}
+
+					binding.* = value;
+				}
+
+				try env.locals.push_one(callable);
 			},
 
 			.push_builtin => |push_builtin| {
@@ -257,6 +301,34 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 				local.* = try env.pop_local();
 			},
 
+			.get_box => {
+				const box = try env.expect(try env.pop_local());
+
+				defer env.discard(box);
+
+				const boxed = box.as_boxed() orelse {
+					return env.raise(error.TypeMismatch, "{typename} is not unboxable", .{.typename = box.typename()});
+				};
+
+				try env.locals.push_one(if (boxed.*) |value| value.acquire() else null);
+			},
+
+			.set_box => {
+				const box = try env.expect(try env.pop_local());
+
+				errdefer env.discard(box);
+
+				const boxed = box.as_boxed() orelse {
+					return env.raise(error.TypeMismatch, "{typename} is not unboxable", .{.typename = box.typename()});
+				};
+
+				if (boxed.*) |value| {
+					env.discard(value);
+				}
+
+				boxed.* = box;
+			},
+
 			.get_dynamic => {
 				const index = try env.expect(try env.pop_local());
 
@@ -286,15 +358,11 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 					}
 				}
 
-				const index = try env.pop_local() orelse {
+				const index = try env.expect(try env.pop_local());
-					return env.raise(error.TypeMismatch, "nil is not a valid index");
-				};
 
 				defer env.discard(index);
 
-				const indexable = try env.pop_local() orelse {
+				const indexable = try env.expect(try env.pop_local());
-					return env.raise(error.TypeMismatch, "nil is not a valid indexable");
-				};
 
 				defer env.discard(indexable);
 
@@ -307,7 +375,7 @@ pub fn execute(chunk: Self, env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeE
 
 					defer env.discard(callable);
 
-					const call_frame = try env.push_frame(call);
+					const call_frame = try env.push_frame(callable, call);
 
 					defer env.pop_frame();
 
@@ -494,14 +562,27 @@ pub fn free(self: *Self, env: *kym.RuntimeEnv) void {
 	self.constants.free();
 	self.opcodes.free();
 	env.discard(self.name);
+
+	if (self.bindings.len != 0) {
+		for (self.bindings) |binding| {
+			if (binding) |value| {
+				env.discard(value);
+			}
+		}
+
+		env.allocator.deallocate(self.bindings);
+	}
+
+	self.bindings = &.{};
 }
 
-pub fn make(env: *kym.RuntimeEnv, name: []const coral.io.Byte, environment: *const tree.Environment) kym.RuntimeError!Self {
+pub fn make(env: *kym.RuntimeEnv, name: *const kym.RuntimeRef, environment: *const tree.Environment) kym.RuntimeError!Self {
 	var chunk = Self{
-		.name = try env.new_symbol(name),
+		.name = name.acquire(),
 		.opcodes = OpcodeList.make(env.allocator),
 		.constants = ConstList.make(env.allocator),
-		.arity = 0,
+		.bindings = &.{},
+		.arity = environment.argument_count,
 	};
 
 	var compiler = Compiler{
@@ -515,33 +596,33 @@ pub fn make(env: *kym.RuntimeEnv, name: []const coral.io.Byte, environment: *con
 }
 
 fn syscall_import(env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
-	return env.import(file.Path.from(&.{try env.unbox_string(try frame.get_arg(env, 0))}));
+	return env.import(file.Path.from(&.{try env.unwrap_string(try frame.expect_arg(env, 0))}));
 }
 
 fn syscall_print(env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
-	env.print(try env.unbox_string(try frame.get_arg(env, 0)));
+	env.print(try env.unwrap_string(try frame.expect_arg(env, 0)));
 
 	return null;
 }
 
 fn syscall_vec2(env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
-	const x = @as(f32, @floatCast(try env.unbox_float(try frame.get_arg(env, 0))));
+	const x = @as(f32, @floatCast(try env.unwrap_float(try frame.expect_arg(env, 0))));
 
 	if (frame.has_arg(env, 1)) |y| {
-		return env.new_vector2(x, @floatCast(try env.unbox_float(y)));
+		return env.new_vector2(x, @floatCast(try env.unwrap_float(y)));
 	}
 
 	return env.new_vector2(x, x);
 }
 
 fn syscall_vec3(env: *kym.RuntimeEnv, frame: kym.Frame) kym.RuntimeError!?*kym.RuntimeRef {
-	const x = @as(f32, @floatCast(try env.unbox_float(try frame.get_arg(env, 0))));
+	const x = @as(f32, @floatCast(try env.unwrap_float(try frame.expect_arg(env, 0))));
 
 	if (frame.has_arg(env, 1)) |y| {
 		return env.new_vector3(
 			x,
-			@floatCast(try env.unbox_float(y)),
+			@floatCast(try env.unwrap_float(y)),
-			@floatCast(try env.unbox_float(try frame.get_arg(env, 2))),
+			@floatCast(try env.unwrap_float(try frame.expect_arg(env, 2))),
 		);
 	}
 
@@ -559,7 +640,11 @@ fn typeinfo_call(env: *kym.RuntimeEnv, userdata: []coral.io.Byte, frame: kym.Fra
 	const chunk = @as(*Self, @ptrCast(@alignCast(userdata)));
 
 	if (frame.arg_count < chunk.arity) {
-		return env.raise(error.BadOperation, "expected more arguments");
+		return env.raise(error.BadOperation, "expected `{expected_count}` {noun}, {provided_count} provided", .{
+			.expected_count = frame.arg_count,
+			.provided_count = chunk.arity,
+			.noun = if (frame.arg_count == 1) "argument" else "arguments",
+		});
 	}
 
 	return chunk.execute(env, frame);

source/ona/kym/Compiler.zig

@@ -21,7 +21,7 @@ fn compile_argument(self: Self, environment: *const tree.Environment, initial_ar
 	var argument_count = @as(u8, 0);
 
 	while (maybe_argument) |argument| {
-		try self.compile_expression(environment, argument);
+		try self.compile_expression(environment, argument, null);
 
 		maybe_argument = argument.next;
 		argument_count += 1;
@@ -30,7 +30,7 @@ fn compile_argument(self: Self, environment: *const tree.Environment, initial_ar
 	return argument_count;
 }
 
-fn compile_expression(self: Self, environment: *const tree.Environment, expression: *const Expr) kym.RuntimeError!void {
+fn compile_expression(self: Self, environment: *const tree.Environment, expression: *const Expr, name: ?[]const coral.io.Byte) kym.RuntimeError!void {
 	const number_format = coral.utf8.DecimalFormat{
 		.delimiter = "_",
 		.positive_prefix = .none,
@@ -68,7 +68,7 @@ fn compile_expression(self: Self, environment: *const tree.Environment, expressi
 			var field_count = @as(u32, 0);
 
 			while (table_entry) |entry| : (table_entry = entry.next) {
-				try self.compile_expression(environment, entry);
+				try self.compile_expression(environment, entry, null);
 
 				if (entry.kind != .key_value) {
 					try self.chunk.opcodes.push_one(.push_top);
@@ -81,29 +81,42 @@ fn compile_expression(self: Self, environment: *const tree.Environment, expressi
 		},
 
 		.key_value => |key_value| {
-			try self.compile_expression(environment, key_value.value);
+			try self.compile_expression(environment, key_value.value, null);
-			try self.compile_expression(environment, key_value.key);
+			try self.compile_expression(environment, key_value.key, null);
 		},
 
 		.lambda_construct => |lambda_construct| {
-			var chunk = try Chunk.make(self.env, "<lambda>", lambda_construct.environment);
+			const anonymous_chunk_name = try self.env.new_symbol(name orelse "<lambda>");
+
+			defer self.env.discard(anonymous_chunk_name);
+
+			var chunk = try Chunk.make(self.env, anonymous_chunk_name, lambda_construct.environment);
 
 			errdefer chunk.free(self.env);
 
+			if (lambda_construct.environment.capture_count == 0) {
 				try self.chunk.opcodes.push_one(.{.push_const = try self.declare_chunk(chunk)});
+			} else {
+				const lambda_captures = lambda_construct.environment.get_captures();
+				var index = lambda_captures.len;
 
-			if (lambda_construct.environment.capture_count != 0) {
+				while (index != 0) {
-				for (lambda_construct.environment.captures[0 .. lambda_construct.environment.capture_count]) |capture| {
+					index -= 1;
-					try self.chunk.opcodes.push_one(.{.push_local = environment.captures[capture]});
+
+					try self.chunk.opcodes.push_one(switch (lambda_captures[index]) {
+						.declaration_index => |declaration_index| .{.push_local = declaration_index},
+						.capture_index => |capture_index| .{.push_binding = capture_index},
+					});
 				}
 
-				try self.chunk.opcodes.push_one(.{.push_closure = lambda_construct.environment.capture_count});
+				try self.chunk.opcodes.push_one(.{.push_const = try self.declare_chunk(chunk)});
+				try self.chunk.opcodes.push_one(.{.bind = lambda_construct.environment.capture_count});
 			}
 		},
 
 		.binary_op => |binary_op| {
-			try self.compile_expression(environment, binary_op.lhs_operand);
+			try self.compile_expression(environment, binary_op.lhs_operand, null);
-			try self.compile_expression(environment, binary_op.rhs_operand);
+			try self.compile_expression(environment, binary_op.rhs_operand, null);
 
 			try self.chunk.opcodes.push_one(switch (binary_op.operation) {
 				.addition => .add,
@@ -119,7 +132,7 @@ fn compile_expression(self: Self, environment: *const tree.Environment, expressi
 		},
 
 		.unary_op => |unary_op| {
-			try self.compile_expression(environment, unary_op.operand);
+			try self.compile_expression(environment, unary_op.operand, null);
 
 			try self.chunk.opcodes.push_one(switch (unary_op.operation) {
 				.boolean_negation => .not,
@@ -130,11 +143,11 @@ fn compile_expression(self: Self, environment: *const tree.Environment, expressi
 		.invoke => |invoke| {
 			const argument_count = try self.compile_argument(environment, invoke.argument);
 
-			try self.compile_expression(environment, invoke.object);
+			try self.compile_expression(environment, invoke.object, null);
 			try self.chunk.opcodes.push_one(.{.call = argument_count});
 		},
 
-		.group => |group| try self.compile_expression(environment, group),
+		.group => |group| try self.compile_expression(environment, group, null),
 		.import_builtin => try self.chunk.opcodes.push_one(.{.push_builtin = .import}),
 		.print_builtin => try self.chunk.opcodes.push_one(.{.push_builtin = .print}),
 		.vec2_builtin => try self.chunk.opcodes.push_one(.{.push_builtin = .vec2}),
@@ -145,56 +158,63 @@ fn compile_expression(self: Self, environment: *const tree.Environment, expressi
 				return self.chunk.opcodes.push_one(.{.push_local = index});
 			}
 
-			if (get_capture_index(environment, declaration_get.declaration)) |index| {
+			if (try self.get_binding_index(environment, declaration_get.declaration)) |index| {
-				try self.chunk.opcodes.push_one(.push_self);
+				try self.chunk.opcodes.push_one(.{.push_binding = index});
-				try self.chunk.opcodes.push_one(.{.push_const = try self.declare_fixed(index)});
 
-				return self.chunk.opcodes.push_one(.get_dynamic);
+				if (is_declaration_boxed(declaration_get.declaration)) {
+					try self.chunk.opcodes.push_one(.get_box);
 				}
 
-			return self.env.raise(error.IllegalState, "local out of scope");
+				return;
+			}
+
+			return self.env.raise(error.IllegalState, "local out of scope", .{});
 		},
 
 		.declaration_set => |declaration_set| {
-			try self.compile_expression(environment, declaration_set.assign);
-
 			if (get_local_index(environment, declaration_set.declaration)) |index| {
+				try self.compile_expression(environment, declaration_set.assign, null);
+
 				return self.chunk.opcodes.push_one(.{.set_local = index});
 			}
 
-			if (get_capture_index(environment, declaration_set.declaration)) |index| {
+			if (try self.get_binding_index(environment, declaration_set.declaration)) |index| {
-				try self.chunk.opcodes.push_one(.push_self);
+				try self.chunk.opcodes.push_one(.{.push_binding = index});
-				try self.chunk.opcodes.push_one(.{.push_const = try self.declare_fixed(index)});
+				try self.compile_expression(environment, declaration_set.assign, null);
 
-				return self.chunk.opcodes.push_one(.set_dynamic);
+				if (is_declaration_boxed(declaration_set.declaration)) {
+					try self.chunk.opcodes.push_one(.set_box);
 				}
 
-			return self.env.raise(error.IllegalState, "local out of scope");
+				return;
+			}
+
+			return self.env.raise(error.IllegalState, "local out of scope", .{});
 		},
 
 		.field_get => |field_get| {
-			try self.compile_expression(environment, field_get.object);
+			try self.compile_expression(environment, field_get.object, null);
 			try self.chunk.opcodes.push_one(.{.push_const = try self.declare_symbol(field_get.identifier)});
 			try self.chunk.opcodes.push_one(.get_dynamic);
 		},
 
 		.field_set => |field_set| {
-			try self.compile_expression(environment, field_set.object);
+			try self.compile_expression(environment, field_set.object, null);
 			try self.chunk.opcodes.push_one(.{.push_const = try self.declare_symbol(field_set.identifier)});
-			try self.compile_expression(environment, field_set.assign);
+			try self.compile_expression(environment, field_set.assign, null);
 			try self.chunk.opcodes.push_one(.set_dynamic);
 		},
 
 		.subscript_get => |subscript_get| {
-			try self.compile_expression(environment, subscript_get.object);
+			try self.compile_expression(environment, subscript_get.object, null);
-			try self.compile_expression(environment, subscript_get.index);
+			try self.compile_expression(environment, subscript_get.index, null);
 			try self.chunk.opcodes.push_one(.get_dynamic);
 		},
 
 		.subscript_set => |subscript_set| {
-			try self.compile_expression(environment, subscript_set.object);
+			try self.compile_expression(environment, subscript_set.object, null);
-			try self.compile_expression(environment, subscript_set.index);
+			try self.compile_expression(environment, subscript_set.index, null);
-			try self.compile_expression(environment, subscript_set.assign);
+			try self.compile_expression(environment, subscript_set.assign, null);
 			try self.chunk.opcodes.push_one(.set_dynamic);
 		},
 	}
@@ -217,14 +237,17 @@ fn compile_statement(self: Self, environment: *const tree.Environment, initial_s
 		switch (current_statement.kind) {
 			.@"return" => |@"return"| {
 				if (@"return".returned_expression) |expression| {
-					try self.compile_expression(environment, expression);
+					try self.compile_expression(environment, expression, null);
 				} else {
 					try self.chunk.opcodes.push_one(.push_nil);
 				}
+
+				// TODO: Omit ret calls at ends of chunk.
+				try self.chunk.opcodes.push_one(.ret);
 			},
 
 			.@"while" => |@"while"| {
-				try self.compile_expression(environment, @"while".loop_expression);
+				try self.compile_expression(environment, @"while".loop_expression, null);
 				try self.chunk.opcodes.push_one(.{.jf = 0});
 
 				const origin_index = @as(u32, @intCast(self.chunk.opcodes.values.len - 1));
@@ -232,12 +255,12 @@ fn compile_statement(self: Self, environment: *const tree.Environment, initial_s
 				_ = try self.compile_statement(environment, @"while".loop);
 				self.chunk.opcodes.values[origin_index].jf = @intCast(self.chunk.opcodes.values.len - 1);
 
-				try self.compile_expression(environment, @"while".loop_expression);
+				try self.compile_expression(environment, @"while".loop_expression, null);
 				try self.chunk.opcodes.push_one(.{.jt = origin_index});
 			},
 
 			.@"if" => |@"if"| {
-				try self.compile_expression(environment, @"if".then_expression);
+				try self.compile_expression(environment, @"if".then_expression, null);
 				try self.chunk.opcodes.push_one(.{.jf = 0});
 
 				const origin_index = @as(u32, @intCast(self.chunk.opcodes.values.len - 1));
@@ -251,15 +274,15 @@ fn compile_statement(self: Self, environment: *const tree.Environment, initial_s
 			},
 
 			.declare => |declare| {
-				try self.compile_expression(environment, declare.initial_expression);
+				try self.compile_expression(environment, declare.initial_expression, declare.declaration.identifier);
 
-				if (declare.declaration.is_captured and !declare.declaration.is_readonly) {
+				if (is_declaration_boxed(declare.declaration)) {
 					try self.chunk.opcodes.push_one(.push_boxed);
 				}
 			},
 
 			.top_expression => |top_expression| {
-				try self.compile_expression(environment, top_expression);
+				try self.compile_expression(environment, top_expression, null);
 
 				if (top_expression.kind == .invoke) {
 					try self.chunk.opcodes.push_one(.pop);
@@ -271,12 +294,16 @@ fn compile_statement(self: Self, environment: *const tree.Environment, initial_s
 	}
 }
 
+const constants_max = @as(usize, coral.math.max_int(@typeInfo(u16).Int));
+
 fn declare_chunk(self: Self, chunk: Chunk) kym.RuntimeError!u16 {
 	if (self.chunk.constants.values.len == coral.math.max_int(@typeInfo(u16).Int)) {
-		return self.env.raise(error.BadSyntax, "chunks cannot contain more than 65,535 constants");
+		return self.env.raise(error.BadSyntax, "chunks cannot contain more than {max} constants", .{
+			.max = @as(usize, coral.math.max_int(@typeInfo(u16).Int)),
+		});
 	}
 
-	const constant = try self.env.new_dynamic(coral.io.bytes_of(&chunk).ptr, Chunk.typeinfo);
+	const constant = try self.env.new_dynamic(coral.io.bytes_of(&chunk), Chunk.typeinfo);
 
 	errdefer self.env.discard(constant);
 
@@ -286,8 +313,10 @@ fn declare_chunk(self: Self, chunk: Chunk) kym.RuntimeError!u16 {
 }
 
 fn declare_fixed(self: Self, fixed: kym.Fixed) kym.RuntimeError!u16 {
-	if (self.chunk.constants.values.len == coral.math.max_int(@typeInfo(u16).Int)) {
+	if (self.chunk.constants.values.len == constants_max) {
-		return self.env.raise(error.BadSyntax, "chunks cannot contain more than 65,535 constants");
+		return self.env.raise(error.BadSyntax, "chunks cannot contain more than {max} constants", .{
+			.max = constants_max,
+		});
 	}
 
 	const constant = try self.env.new_fixed(fixed);
@@ -300,8 +329,10 @@ fn declare_fixed(self: Self, fixed: kym.Fixed) kym.RuntimeError!u16 {
 }
 
 fn declare_float(self: Self, float: kym.Float) kym.RuntimeError!u16 {
-	if (self.chunk.constants.values.len == coral.math.max_int(@typeInfo(u16).Int)) {
+	if (self.chunk.constants.values.len == constants_max) {
-		return self.env.raise(error.BadSyntax, "chunks cannot contain more than 65,535 constants");
+		return self.env.raise(error.BadSyntax, "chunks cannot contain more than {max} constants", .{
+			.max = constants_max,
+		});
 	}
 
 	const constant = try self.env.new_float(float);
@@ -314,8 +345,10 @@ fn declare_float(self: Self, float: kym.Float) kym.RuntimeError!u16 {
 }
 
 fn declare_string(self: Self, string: []const coral.io.Byte) kym.RuntimeError!u16 {
-	if (self.chunk.constants.values.len == coral.math.max_int(@typeInfo(u16).Int)) {
+	if (self.chunk.constants.values.len == constants_max) {
-		return self.env.raise(error.BadSyntax, "chunks cannot contain more than 65,535 constants");
+		return self.env.raise(error.BadSyntax, "chunks cannot contain more than {max} constants", .{
+			.max = constants_max,
+		});
 	}
 
 	const constant = try self.env.new_string(string);
@@ -328,8 +361,10 @@ fn declare_string(self: Self, string: []const coral.io.Byte) kym.RuntimeError!u1
 }
 
 fn declare_symbol(self: Self, symbol: []const coral.io.Byte) kym.RuntimeError!u16 {
-	if (self.chunk.constants.values.len == coral.math.max_int(@typeInfo(u16).Int)) {
+	if (self.chunk.constants.values.len == constants_max) {
-		return self.env.raise(error.BadSyntax, "chunks cannot contain more than 65,535 constants");
+		return self.env.raise(error.BadSyntax, "chunks cannot contain more than {max} constants", .{
+			.max = constants_max,
+		});
 	}
 
 	const constant = try self.env.new_symbol(symbol);
@@ -341,30 +376,42 @@ fn declare_symbol(self: Self, symbol: []const coral.io.Byte) kym.RuntimeError!u1
 	return @intCast(self.chunk.constants.values.len - 1);
 }
 
-pub fn get_capture_index(self: *const tree.Environment, declaration: *const tree.Declaration) ?u8 {
+pub fn get_binding_index(self: *const Self, environment: *const tree.Environment, declaration: *const tree.Declaration) kym.RuntimeError!?u8 {
-	if (self.enclosing) |enclosing_environment| {
+	var binding_index = @as(u8, 0);
-		var capture_index = @as(u8, 0);
 
-		while (capture_index < self.capture_count) : (capture_index += 1) {
+	while (binding_index < environment.capture_count) : (binding_index += 1) {
-			if (&enclosing_environment.local_declarations[capture_index] == declaration) {
+		var capture = &environment.captures[binding_index];
-				return capture_index;
+		var target_environment = environment.enclosing orelse return null;
+
+		while (capture.* == .capture_index) {
+			capture = &target_environment.captures[capture.capture_index];
+			target_environment = target_environment.enclosing orelse return null;
 		}
+
+		try kym.assert(self.env, capture.* == .declaration_index);
+
+		if (&target_environment.declarations[capture.declaration_index] == declaration) {
+			return binding_index;
 		}
 	}
 
 	return null;
 }
 
-pub fn get_local_index(self: *const tree.Environment, declaration: *const tree.Declaration) ?u8 {
+pub fn get_local_index(environment: *const tree.Environment, declaration: *const tree.Declaration) ?u8 {
-	var remaining = self.local_declaration_count;
+	var remaining = environment.declaration_count;
 
 	while (remaining != 0) {
 		remaining -= 1;
 
-		if (&self.local_declarations[remaining] == declaration) {
+		if (&environment.declarations[remaining] == declaration) {
 			return remaining;
 		}
 	}
 
 	return null;
 }
+
+fn is_declaration_boxed(declaration: *const tree.Declaration) bool {
+	return declaration.is.captured and !declaration.is.readonly;
+}

source/ona/kym/Expr.zig

@@ -174,11 +174,17 @@ pub fn parse(root: *tree.Root, stream: *tokens.Stream, environment: *tree.Enviro
 
 		return root.create_expr(.{
 			.kind = switch (expression.kind) {
-				.declaration_get => |declaration_get| .{
+				.declaration_get => |declaration_get| convert: {
+					if (declaration_get.declaration.is.readonly) {
+						return root.report_error(stream, "readonly declarations cannot be re-assigned", .{});
+					}
+
+					break: convert .{
 						.declaration_set = .{
 							.assign = try parse(root, stream, environment),
 							.declaration = declaration_get.declaration,
 						},
+					};
 				},
 
 				.field_get => |field_get| .{
@@ -414,15 +420,13 @@ fn parse_operand(root: *tree.Root, stream: *tokens.Stream, environment: *tree.En
 			stream.skip_newlines();
 
 			return root.create_expr(.{
-				.next = null,
-
 				.kind = .{
 					.declaration_get = .{
 						.declaration = (try environment.resolve_declaration(identifier)) orelse {
 							return root.report_error(stream, "undefined identifier `{identifier}`", .{
 								.identifier = identifier,
 							});
-						},
+						}
 					},
 				},
 			});
@@ -445,13 +449,9 @@ fn parse_operand(root: *tree.Root, stream: *tokens.Stream, environment: *tree.En
 					else => return root.report_error(stream, "expected identifier", .{}),
 				};
 
-				if (try lambda_environment.declare(identifier) == null) {
+				_ = lambda_environment.declare_argument(identifier) catch |declare_error| {
-					return root.report_error(stream, "declaration `{identifier}` already exists", .{
+					return root.report_declare_error(stream, identifier, declare_error);
-						.identifier = identifier,
+				};
-					});
-				}
-
-				lambda_environment.argument_count += 1;
 
 				stream.skip_newlines();
 

source/ona/kym/Stmt.zig

@@ -93,18 +93,13 @@ pub fn parse(root: *tree.Root, stream: *tokens.Stream, environment: *tree.Enviro
 		},
 
 		.keyword_var, .keyword_let => {
-			const storage_token = stream.token;
+			const is_constant = stream.token == .keyword_let;
 
 			stream.skip_newlines();
 
 			const identifier = switch (stream.token) {
 				.identifier => |identifier| identifier,
-
+				else => return root.report_error(stream, "expected identifier after declaration", .{}),
-				else => {
-					return root.report_error(stream, "expected identifier after `{storage}` declaration statement", .{
-						.storage = storage_token.text()
-					});
-				},
 			};
 
 			stream.skip_newlines();
@@ -122,10 +117,16 @@ pub fn parse(root: *tree.Root, stream: *tokens.Stream, environment: *tree.Enviro
 					.declare = .{
 						.initial_expression = try Expr.parse(root, stream, environment),
 
-						.declaration = (try root.environment.declare(identifier)) orelse {
+						.declaration = declare: {
-							return root.report_error(stream, "declaration `{identifier}` already exists", .{
+							if (is_constant) {
-								.identifier = identifier,
+								break: declare environment.declare_constant(identifier) catch |declaration_error| {
-							});
+									return root.report_declare_error(stream, identifier, declaration_error);
+								};
+							}
+
+							break: declare environment.declare_variable(identifier) catch |declaration_error| {
+								return root.report_declare_error(stream, identifier, declaration_error);
+							};
 						},
 					},
 				},

source/ona/kym/tree.zig

@@ -8,19 +8,31 @@ const tokens = @import("./tokens.zig");
 
 pub const Declaration = struct {
 	identifier: []const coral.io.Byte,
-	is_readonly: bool = false,
+
-	is_captured: bool = false,
+	is: packed struct {
+		readonly: bool = false,
+		captured: bool = false,
+	} = .{},
 };
 
 pub const Environment = struct {
-	captures: [capture_max]u8 = [_]u8{0} ** capture_max,
+	captures: [capture_max]Capture = [_]Capture{.{.declaration_index = 0}} ** capture_max,
 	capture_count: u8 = 0,
-	local_declarations: [declaration_max]Declaration = [_]Declaration{.{.identifier = ""}} ** declaration_max,
+	declarations: [declaration_max]Declaration = [_]Declaration{.{.identifier = ""}} ** declaration_max,
-	local_declaration_count: u8 = 0,
+	declaration_count: u8 = 0,
 	argument_count: u8 = 0,
 	statement: ?*const Stmt = null,
 	enclosing: ?*Environment = null,
 
+	pub const Capture = union (enum) {
+		declaration_index: u8,
+		capture_index: u8,
+	};
+
+	pub const DeclareError = coral.io.AllocationError || error {
+		DeclarationExists,
+	};
+
 	const capture_max = coral.math.max_int(@typeInfo(u8).Int);
 
 	const declaration_max = coral.math.max_int(@typeInfo(u8).Int);
@@ -31,48 +43,96 @@ pub const Environment = struct {
 		});
 	}
 
-	pub fn declare(self: *Environment, identifier: []const coral.io.Byte) coral.io.AllocationError!?*const Declaration {
+	fn declare(self: *Environment, declaration: Declaration) DeclareError!*const Declaration {
-		if (self.local_declaration_count == self.local_declarations.len) {
+		if (self.declaration_count == self.declarations.len) {
 			return error.OutOfMemory;
 		}
 
-		const declaration = &self.local_declarations[self.local_declaration_count];
+		{
-
-		declaration.* = .{.identifier = identifier};
-		self.local_declaration_count += 1;
-
-		return declaration;
-	}
-
-	pub fn resolve_declaration(self: *Environment, identifier: []const coral.io.Byte) coral.io.AllocationError!?*const Declaration {
 			var environment = self;
-		var ancestry = @as(usize, 0);
 
-		while (true) : (ancestry += 1) {
+			while (true) {
-			var remaining_count = self.local_declaration_count;
+				var remaining_count = environment.declaration_count;
 
 				while (remaining_count != 0) {
 					remaining_count -= 1;
 
-				const declaration = &self.local_declarations[remaining_count];
+					if (coral.io.are_equal(environment.declarations[remaining_count].identifier, declaration.identifier)) {
+						return error.DeclarationExists;
+					}
+				}
+
+				environment = environment.enclosing orelse break;
+			}
+		}
+
+		const declaration_slot = &self.declarations[self.declaration_count];
+
+		declaration_slot.* = declaration;
+		self.declaration_count += 1;
+
+		return declaration_slot;
+	}
+
+	pub fn declare_argument(self: *Environment, identifier: []const coral.io.Byte) DeclareError!*const Declaration {
+		coral.debug.assert(self.declaration_count <= self.argument_count);
+
+		defer self.argument_count += 1;
+
+		return self.declare(.{
+			.identifier = identifier,
+			.is = .{.readonly = true},
+		});
+	}
+
+	pub fn declare_constant(self: *Environment, identifier: []const coral.io.Byte) DeclareError!*const Declaration {
+		return self.declare(.{
+			.identifier = identifier,
+			.is = .{.readonly = true},
+		});
+	}
+
+	pub fn declare_variable(self: *Environment, identifier: []const coral.io.Byte) DeclareError!*const Declaration {
+		return self.declare(.{.identifier = identifier});
+	}
+
+	pub fn resolve_declaration(self: *Environment, identifier: []const coral.io.Byte) coral.io.AllocationError!?*const Declaration {
+		var environment = self;
+		var ancestry = @as(u32, 0);
+
+		while (true) : (ancestry += 1) {
+			var remaining_count = environment.declaration_count;
+
+			while (remaining_count != 0) {
+				remaining_count -= 1;
+
+				const declaration = &environment.declarations[remaining_count];
 
 				if (coral.io.are_equal(declaration.identifier, identifier)) {
 					if (ancestry != 0) {
-						declaration.is_captured = true;
+						declaration.is.captured = true;
 						environment = self;
+						ancestry -= 1;
 
 						while (ancestry != 0) : (ancestry -= 1) {
-							if (environment.capture_count == self.captures.len) {
+							if (environment.capture_count == environment.captures.len) {
 								return error.OutOfMemory;
 							}
 
-							environment.captures[environment.capture_count] = remaining_count;
-							environment.capture_count += 1;
-
 							coral.debug.assert(environment.enclosing != null);
 
-							environment = environment.enclosing.?;
+							const enclosing_environment = environment.enclosing.?;
+
+							environment.captures[environment.capture_count] = .{
+								.capture_index = enclosing_environment.capture_count
+							};
+
+							environment.capture_count += 1;
+							environment = enclosing_environment;
 						}
+
+						environment.captures[environment.capture_count] = .{.declaration_index = remaining_count};
+						environment.capture_count += 1;
 					}
 
 					return declaration;
@@ -82,6 +142,14 @@ pub const Environment = struct {
 			environment = environment.enclosing orelse return null;
 		}
 	}
+
+	pub fn get_captures(self: *const Environment) []const Capture {
+		return self.captures[0 .. self.capture_count];
+	}
+
+	pub fn get_declarations(self: *const Environment) []const Declaration {
+		return self.declarations[0 .. self.declaration_count];
+	}
 };
 
 pub const ParseError = coral.io.AllocationError || error {
@@ -106,6 +174,16 @@ pub const Root = struct {
 		return error.BadSyntax;
 	}
 
+	pub fn report_declare_error(self: *Root, stream: *tokens.Stream, identifier: []const coral.io.Byte, @"error": Environment.DeclareError) ParseError {
+		return switch (@"error") {
+			error.OutOfMemory => error.OutOfMemory,
+
+			error.DeclarationExists => self.report_error(stream, "declaration `{identifier}` already exists", .{
+				.identifier = identifier,
+			}),
+		};
+	}
+
 	pub fn create_expr(self: *Root, expr: Expr) coral.io.AllocationError!*Expr {
 		return coral.io.allocate_one(self.arena.as_allocator(), expr);
 	}