feat: update alien-signals

packages/charm/src/__tests__/core/computed.spec.luau

@@ -1,13 +1,13 @@
 local core = require("../../core")
 local suite = require("../../../../../test/suite")
 
-local atom = core.atom
 local computed = core.computed
 local effect = core.effect
+local signal = core.signal
 local test = suite.test
 
 test("should correctly propagate changes through computed core", function()
-	local src = atom(0)
+	local src, setSrc = signal(0)
 	local c1 = computed(function()
 		return src() % 2
 	end)
@@ -19,15 +19,15 @@ test("should correctly propagate changes through computed core", function()
 	end)
 
 	c3()
-	src(1) -- c1 -> dirty, c2 -> toCheckDirty, c3 -> toCheckDirty
+	setSrc(1) -- c1 -> dirty, c2 -> toCheckDirty, c3 -> toCheckDirty
 	c2() -- c1 -> none, c2 -> none
-	src(3) -- c1 -> dirty, c2 -> toCheckDirty
+	setSrc(3) -- c1 -> dirty, c2 -> toCheckDirty
 
 	assert(c3() == 1, "bad final value")
 end)
 
 test("should propagate updated source value through chained computations", function()
-	local src = atom(0)
+	local src, setSrc = signal(0)
 	local a = computed(function()
 		return src()
 	end)
@@ -42,12 +42,12 @@ test("should propagate updated source value through chained computations", funct
 	end)
 
 	assert(d() == 0, "bad initial value")
-	src(2)
+	setSrc(2)
 	assert(d() == 2, "bad updated value")
 end)
 
 test("should handle flags are indirectly updated during checkDirty", function()
-	local a = atom(false)
+	local a, setA = signal(false)
 	local b = computed(function()
 		return a()
 	end)
@@ -61,29 +61,29 @@ test("should handle flags are indirectly updated during checkDirty", function()
 	end)
 
 	assert(d() == false, "bad initial value")
-	a(true)
+	setA(true)
 	assert(d() == true, "bad updated value")
 end)
 
-test("should not update if the atom value is reverted", function()
+test("should not update if the signal value is reverted", function()
 	local times = 0
 
-	local src = atom(0)
+	local src, setSrc = signal(0)
 	local c1 = computed(function()
 		times += 1
 		return src()
 	end)
 	c1()
 	assert(times == 1, "computed did not run")
-	src(1)
+	setSrc(1)
-	src(0)
+	setSrc(0)
 	c1()
 	assert(times == 1, "computed ran when it should not")
 end)
 
 test("should receive previous value", function()
 	local calls = {}
-	local src = atom(0)
+	local src, setSrc = signal(0)
 	local c1 = computed(function(current): number
 		local incoming = src()
 		return if current == incoming or incoming % 2 == 1 then current or incoming else incoming
@@ -93,12 +93,12 @@ test("should receive previous value", function()
 		table.insert(calls, c1())
 	end)
 
-	src(2)
+	setSrc(2)
-	src(3)
+	setSrc(3)
 	assert(c1() == 2, "should skip odd value")
 
-	src(4)
+	setSrc(4)
-	src(5)
+	setSrc(5)
 	assert(c1() == 4, "should skip odd value")
 	assert(table.concat(calls) == "024", `should only call on even updates, got {table.concat(calls)}`)
 end)

packages/charm/src/__tests__/core/effect.spec.luau

@@ -5,16 +5,16 @@ local computed = core.computed
 local effect = core.effect
 local effectScope = core.effectScope
 local endBatch = core.endBatch
-local setActiveSub = core.setActiveSub
 local onCleanup = core.onCleanup
-local atom = core.atom
+local setActiveSub = core.setActiveSub
+local signal = core.signal
 local startBatch = core.startBatch
 local test = suite.test
 
 test("should clear subscriptions when untracked by all subscribers", function()
 	local bRunTimes = 0
 
-	local a = atom(1)
+	local a, setA = signal(1)
 	local b = computed(function()
 		bRunTimes += 1
 		return a() * 2
@@ -24,15 +24,15 @@ test("should clear subscriptions when untracked by all subscribers", function()
 	end)
 
 	assert(bRunTimes == 1, "should run initially")
-	a(2)
+	setA(2)
 	assert(bRunTimes == 2, "should run after change")
 	stopEffect()
-	a(3)
+	setA(3)
 	assert(bRunTimes == 2, "should not run after stop")
 end)
 
 test("should not run untracked inner effect", function()
-	local a = atom(3)
+	local a, setA = signal(3)
 	local b = computed(function()
 		return a() > 0
 	end)
@@ -47,14 +47,14 @@ test("should not run untracked inner effect", function()
 		end
 	end)
 
-	a(2)
+	setA(2)
-	a(1)
+	setA(1)
-	a(0)
+	setA(0)
 end)
 
 test("should run outer effect first", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(1)
+	local b, setB = signal(1)
 
 	effect(function()
 		if a() > 0 then
@@ -68,13 +68,13 @@ test("should run outer effect first", function()
 	end)
 
 	startBatch()
-	b(0)
+	setB(0)
-	a(0)
+	setA(0)
 	endBatch()
 end)
 
 test("should not trigger inner effect when resolve maybe dirty", function()
-	local a = atom(0)
+	local a, setA = signal(0)
 	local b = computed(function()
 		return a() % 2
 	end)
@@ -91,68 +91,66 @@ test("should not trigger inner effect when resolve maybe dirty", function()
 		end)
 	end)
 
-	a(2)
+	setA(2)
 end)
 
-test("should trigger inner effects in sequence", function()
+test("should notify inner effects in the same order as non-inner effects", function()
-	local a = atom(0)
+	local getA, setA = signal(0)
-	local b = atom(0)
+	local getB, setB = signal(0)
 	local c = computed(function()
-		return a() - b()
+		return getA() - getB()
+	end)
+	local order1 = {}
+	local order2 = {}
+	local order3 = {}
+
+	effect(function()
+		table.insert(order1, "effect1")
+		getA()
+	end)
+	effect(function()
+		table.insert(order1, "effect2")
+		getA()
+		getB()
 	end)
-	local order: { string } = {}
 
 	effect(function()
 		c()
-
 		effect(function()
-			table.insert(order, "first inner")
+			table.insert(order2, "effect1")
-			a()
+			getA()
 		end)
-
 		effect(function()
-			table.insert(order, "last inner")
+			table.insert(order2, "effect2")
-			a()
+			getA()
-			b()
+			getB()
 		end)
 	end)
 
-	table.clear(order)
-
-	startBatch()
-	b(1)
-	a(1)
-	endBatch()
-
-	assert(table.concat(order, ", ") == "first inner, last inner", `wrong order: {table.concat(order, ", ")}`)
-end)
-
-test("should trigger inner effects in sequence in effect scope", function()
-	local a = atom(0)
-	local b = atom(0)
-	local order: { string } = {}
-
 	effectScope(function()
 		effect(function()
-			table.insert(order, "first inner")
+			table.insert(order3, "effect1")
-			a()
+			getA()
 		end)
-
 		effect(function()
-			table.insert(order, "last inner")
+			table.insert(order3, "effect2")
-			a()
+			getA()
-			b()
+			getB()
 		end)
 	end)
 
-	table.clear(order)
+	table.clear(order1)
+	table.clear(order2)
+	table.clear(order3)
 
 	startBatch()
-	b(1)
+	setB(1)
-	a(1)
+	setA(1)
 	endBatch()
 
-	assert(table.concat(order, ", ") == "first inner, last inner", `wrong order: {table.concat(order, ", ")}`)
+	assert(table.concat(order1, ", ") == "effect2, effect1", "wrong order 1")
+	assert(table.concat(order2, ", ") == "effect2, effect1", "wrong order 2")
+	assert(table.concat(order3, ", ") == "effect2, effect1", "wrong order 3")
 end)
 
 test("should custom effect support batch", function()
@@ -168,13 +166,13 @@ test("should custom effect support batch", function()
 	end
 
 	local logs: { string } = {}
-	local a = atom(0)
+	local a = signal(0)
-	local b = atom(0)
+	local b, setB = signal(0)
 
 	local aa = computed(function()
 		table.insert(logs, "aa-0")
 		if a() == 0 then
-			b(1)
+			setB(1)
 		end
 		table.insert(logs, "aa-1")
 		return nil
@@ -196,8 +194,8 @@ test("should custom effect support batch", function()
 end)
 
 test("should duplicate subscribers do not affect the notify order", function()
-	local src1 = atom(0)
+	local src1, setSrc1 = signal(0)
-	local src2 = atom(0)
+	local src2, setSrc2 = signal(0)
 	local order: { string } = {}
 
 	effect(function()
@@ -215,17 +213,17 @@ test("should duplicate subscribers do not affect the notify order", function()
 		table.insert(order, "b")
 		src1()
 	end)
-	src2(1) -- src1.subs: a -> b -> a
+	setSrc2(1) -- src1.subs: a -> b -> a
 
 	table.clear(order)
-	src1(src1() + 1)
+	setSrc1(src1() + 1)
 
 	assert(table.concat(order) == "ab", `wrong order: {table.concat(order)}`)
 end)
 
 test("should handle side effect with inner effects", function()
-	local a = atom(0)
+	local a, setA = signal(0)
-	local b = atom(0)
+	local b, setB = signal(0)
 	local order: { string } = {}
 
 	effect(function()
@@ -240,14 +238,14 @@ test("should handle side effect with inner effects", function()
 		assert(table.concat(order) == "ab", `wrong order: {table.concat(order)}`)
 
 		table.clear(order)
-		b(1)
+		setB(1)
-		a(1)
+		setA(1)
 		assert(table.concat(order) == "ba", `wrong order: {table.concat(order)}`)
 	end)
 end)
 
 test("should handle flags are indirectly updated during checkDirty", function()
-	local a = atom(false)
+	local a, setA = signal(false)
 	local b = computed(function()
 		return a()
 	end)
@@ -267,14 +265,14 @@ test("should handle flags are indirectly updated during checkDirty", function()
 		triggers += 1
 	end)
 	assert(triggers == 1, "did not run initially")
-	a(true)
+	setA(true)
 	assert(triggers == 2, "did not update indirectly")
 end)
 
 test("should run cleanups in sequence", function()
 	local order = {}
 
-	local a = atom(false)
+	local a, setA = signal(false)
 	local stopEffect = effect(function()
 		a()
 		onCleanup(function()
@@ -287,7 +285,7 @@ test("should run cleanups in sequence", function()
 
 	assert(table.concat(order) == "", "should not cleanup immediately")
 
-	a(true)
+	setA(true)
 	assert(table.concat(order) == "ab", `bad update: {table.concat(order)}`)
 
 	table.clear(order)
@@ -295,14 +293,14 @@ test("should run cleanups in sequence", function()
 	assert(table.concat(order) == "ab", `bad dispose: {table.concat(order)}`)
 
 	table.clear(order)
-	a(false)
+	setA(false)
 	assert(table.concat(order) == "", "should not cleanup after update")
 end)
 
 test("should run inner effect cleanup", function()
 	local cleanups = 0
 
-	local src = atom(false)
+	local src, setSrc = signal(false)
 	local stopEffect = effect(function()
 		src()
 		effect(function()
@@ -318,18 +316,18 @@ test("should run inner effect cleanup", function()
 	end)
 
 	assert(cleanups == 0, "should not cleanup immediately")
-	src(true)
+	setSrc(true)
 	assert(cleanups == 2, "should cleanup after outer update")
 	stopEffect()
 	assert(cleanups == 4, "should cleanup after outer dispose")
-	src(false)
+	setSrc(false)
 	assert(cleanups == 4, "should not cleanup after update")
 end)
 
 test("should run cleanups outside any evaluation context", function()
 	local calls = 0
-	local a = atom(0)
+	local a, setA = signal(0)
-	local b = atom(0)
+	local b, setB = signal(0)
 	local c = computed(function()
 		if a() == 0 then
 			effect(function()
@@ -348,18 +346,18 @@ test("should run cleanups outside any evaluation context", function()
 	assert(calls == 1, "should run once")
 
 	calls = 0
-	a(1)
+	setA(1)
 	assert(calls == 1, "should run once after a update")
 
 	calls = 0
-	b(1)
+	setB(1)
 	assert(calls == 0, "should not run after b update")
 end)
 
 test("should allow self cleanup", function()
 	local calls = 0
 	local cleanups = 0
-	local a = atom(0)
+	local a, setA = signal(0)
 
 	effect(function(stopEffect)
 		onCleanup(function()
@@ -372,7 +370,7 @@ test("should allow self cleanup", function()
 
 	assert(calls == 1, "should call effect once")
 	assert(cleanups == 1, "should call cleanup once")
-	a(1)
+	setA(1)
 	assert(calls == 1, "should not call effect after a update")
 	assert(cleanups == 1, "should not call cleanup after a update")
 end)

packages/charm/src/__tests__/core/effectScope.spec.luau

@@ -3,12 +3,12 @@ local suite = require("../../../../../test/suite")
 
 local effect = core.effect
 local effectScope = core.effectScope
-local atom = core.atom
+local signal = core.signal
 local onCleanup = core.onCleanup
 local test = suite.test
 
 test("should not trigger after stop", function()
-	local count = atom(1)
+	local count, setCount = signal(1)
 
 	local triggers = 0
 
@@ -19,14 +19,14 @@ test("should not trigger after stop", function()
 		end)
 		assert(triggers == 1, "did not run initially")
 
-		count(2)
+		setCount(2)
 		assert(triggers == 2, "did not run after update")
 	end)
 
-	count(3)
+	setCount(3)
 	assert(triggers == 3, "did not run after update outside scope")
 	stopScope()
-	count(4)
+	setCount(4)
 	assert(triggers == 3, "ran after stop")
 end)
 
@@ -52,7 +52,7 @@ end)
 test("should run indirect effect cleanup", function()
 	local cleanups = 0
 
-	local a = atom(false)
+	local a, setA = signal(false)
 	local stopScope = effectScope(function()
 		effect(function()
 			a()
@@ -63,11 +63,11 @@ test("should run indirect effect cleanup", function()
 	end)
 
 	assert(cleanups == 0, "should not cleanup immediately")
-	a(true)
+	setA(true)
 	assert(cleanups == 1, "should cleanup once")
 	stopScope()
 	assert(cleanups == 2, "should cleanup after outer dispose")
-	a(false)
+	setA(false)
 	assert(cleanups == 2, "should not cleanup after update")
 end)
 

packages/charm/src/__tests__/core/topology.spec.luau

@@ -3,13 +3,13 @@ local suite = require("../../../../../test/suite")
 
 local computed = core.computed
 local effect = core.effect
-local atom = core.atom
+local signal = core.signal
 local describe = suite.describe
 local test = suite.test
 
 --[[
 	Tests adopted with thanks from preact-core implementation at
-	https://github.com/preactjs/core/blob/main/packages/core/test/atom.test.tsx
+	https://github.com/preactjs/signals/blob/main/packages/core/test/signal.test.tsx
 
 	The MIT License (MIT)
 
@@ -43,7 +43,7 @@ describe("graph updates", function()
 		--     C
 		--     |
 		--     D
-		local a = atom(2)
+		local a, setA = signal(2)
 
 		local b = computed(function()
 			return a() - 1
@@ -64,12 +64,12 @@ describe("graph updates", function()
 		assert(computeCalls == 1, "compute should be called once")
 		computeCalls = 0
 
-		a(4)
+		setA(4)
 		d()
 		assert(computeCalls == 1, "compute should drop update")
 	end)
 
-	test("should only update every atom once (diamond graph)", function()
+	test("should only update every signal once (diamond graph)", function()
 		-- In this scenario "D" should only update once when "A" receives
 		-- an update. This is sometimes referred to as the "diamond" scenario.
 		--     A
@@ -77,8 +77,7 @@ describe("graph updates", function()
 		--  B     C
 		--   \   /
 		--     D
-
+		local a, setA = signal("a")
-		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -96,12 +95,12 @@ describe("graph updates", function()
 		assert(d() == "a a", "d should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(d() == "aa aa", "d should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
 
-	test("should only update every atom once (diamond graph + tail)", function()
+	test("should only update every signal once (diamond graph + tail)", function()
 		-- "E" will be likely updated twice if our mark+sweep logic is buggy.
 		--     A
 		--   /   \
@@ -110,8 +109,7 @@ describe("graph updates", function()
 		--     D
 		--     |
 		--     E
-
+		local a, setA = signal("a")
-		local a = atom("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -133,7 +131,7 @@ describe("graph updates", function()
 		assert(e() == "a a", "e should be 'a a'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(e() == "aa aa", "e should be 'aa aa'")
 		assert(spyCalls == 2, "compute should be called only twice")
 	end)
@@ -141,7 +139,7 @@ describe("graph updates", function()
 	test("should bail out if result is the same", function()
 		-- Bail out if value of "B" never changes
 		-- A->B->C
-		local a = atom("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			a()
 			return "foo"
@@ -157,12 +155,12 @@ describe("graph updates", function()
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should be called once")
 
-		a("aa")
+		setA("aa")
 		assert(c() == "foo", "c should be 'foo'")
 		assert(spyCalls == 1, "compute should bail out")
 	end)
 
-	test("should only update every atom once (jagged diamond graph + tails)", function()
+	test("should only update every signal once (jagged diamond graph + tails)", function()
 		-- "F" and "G" will be likely updated twice if our mark+sweep logic is buggy.
 		--     A
 		--   /   \
@@ -173,7 +171,7 @@ describe("graph updates", function()
 		--     E
 		--   /   \
 		--  F     G
-		local a = atom("a")
+		local a, setA = signal("a")
 
 		local b = computed(function()
 			return a()
@@ -222,7 +220,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		a("b")
+		setA("b")
 
 		assert(e() == "b b", "e should be 'b b'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -237,7 +235,7 @@ describe("graph updates", function()
 		fSpyCalls, fSpyTime = 0, 0
 		gSpyCalls, gSpyTime = 0, 0
 
-		a("c")
+		setA("c")
 
 		assert(e() == "c c", "e should be 'c c'")
 		assert(eSpyCalls == 1, "e should run once after update")
@@ -258,7 +256,7 @@ describe("graph updates", function()
 		--    *A
 		--   /   \
 		-- *B     C <- we don't listen to C
-		local a = atom("a")
+		local a, setA = signal("a")
 
 		local b = computed(function()
 			return a()
@@ -273,7 +271,7 @@ describe("graph updates", function()
 		assert(b() == "a", "b should be 'a'")
 		assert(spyCalls == 0, "compute should not run")
 
-		a("aa")
+		setA("aa")
 		assert(b() == "aa", "b should be 'aa'")
 		assert(spyCalls == 0, "compute should not run")
 	end)
@@ -287,7 +285,7 @@ describe("graph updates", function()
 		-- *B     D <- we don't listen to C
 		--  |
 		-- *C
-		local a = atom("a")
+		local a, setA = signal("a")
 		local spyBCalls = 0
 		local spyB = function()
 			spyBCalls += 1
@@ -318,7 +316,7 @@ describe("graph updates", function()
 		spyCCalls = 0
 		unsub()
 
-		a("aa")
+		setA("aa")
 
 		assert(spyBCalls == 0, "b should not run")
 		assert(spyCCalls == 0, "c should not run")
@@ -335,7 +333,7 @@ describe("graph updates", function()
 		--  B     *C <- returns same value every time
 		--   \   /
 		--     D
-		local a = atom("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -353,7 +351,7 @@ describe("graph updates", function()
 		assert(d() == "a c", "d should be 'a c'")
 		spyResult = nil
 
-		a("aa")
+		setA("aa")
 		d()
 		assert(spyResult == "aa c", "d should have returned 'aa c'")
 	end)
@@ -367,7 +365,7 @@ describe("graph updates", function()
 		--  B *C *D
 		--   \ | /
 		--     E
-		local a = atom("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			return a()
 		end)
@@ -389,13 +387,13 @@ describe("graph updates", function()
 		assert(e() == "a c d", "e should be 'a c d'")
 		spyResult = nil
 
-		a("aa")
+		setA("aa")
 		e()
 		assert(spyResult == "aa c d", "e should have returned 'aa c d'")
 	end)
 
 	test("should support lazy branches", function()
-		local a = atom(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			return a()
 		end)
@@ -404,10 +402,10 @@ describe("graph updates", function()
 		end)
 
 		assert(c() == 0, "c should be 0")
-		a(1)
+		setA(1)
 		assert(c() == 1, "c should be 1")
 
-		a(0)
+		setA(0)
 		assert(c() == 0, "c should be 0 again")
 	end)
 
@@ -419,7 +417,7 @@ describe("graph updates", function()
 		-- *B     *C
 		--   \   /
 		--     D
-		local a = atom("a")
+		local a, setA = signal("a")
 		local b = computed(function()
 			a()
 			return "b"
@@ -438,14 +436,14 @@ describe("graph updates", function()
 		assert(d() == "b c", "d should be 'b c'")
 		spyCalls = 0
 
-		a("aa")
+		setA("aa")
 		assert(spyCalls == 0, "d should not run")
 	end)
 end)
 
 describe("error handling", function()
 	test("should keep graph consistent on errors during activation", function()
-		local a = atom(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			error("fail")
 		end)
@@ -459,12 +457,12 @@ describe("error handling", function()
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		a(1)
+		setA(1)
 		assert(c() == 1, "c should recover and return 1")
 	end)
 
 	test("should keep graph consistent on errors in computeds", function()
-		local a = atom(0)
+		local a, setA = signal(0)
 		local b = computed(function()
 			if a() == 1 then
 				error("fail")
@@ -477,14 +475,14 @@ describe("error handling", function()
 
 		assert(c() == 0, "c should be 0")
 
-		a(1)
+		setA(1)
 		local success, result = pcall(function()
 			b()
 		end)
 		assert(not success, "should throw")
 		assert(string.match(result, "fail"), "should throw fail")
 
-		a(2)
+		setA(2)
 		assert(c() == 2, "c should recover and return 2")
 	end)
 end)

packages/charm/src/__tests__/listen.spec.luau

@@ -1,14 +1,14 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-local atom = Charm.atom
+local signal = Charm.signal
 local listen = Charm.listen
 local effect = Charm.effect
 local onCleanup = Charm.onCleanup
 local test = suite.test
 
 test("should listen to selector", function()
-	local source = atom(0)
+	local source, setSource = signal(0)
 	local current, previous
 
 	local unsub = listen(function()
@@ -19,20 +19,20 @@ test("should listen to selector", function()
 	end)
 
 	assert(current == 1 and previous == nil, "should run initially")
-	source(0)
+	setSource(0)
 	assert(current == 1 and previous == nil, "should skip redundant update")
-	source(1)
+	setSource(1)
 	assert(current == 2 and previous == 1, "should run with new value")
 	unsub()
-	source(2)
+	setSource(2)
 	assert(current == 2 and previous == 1, "should not run after unsub")
 end)
 
 test("should run in peek", function()
 	local runs = 0
 	local cleanups = 0
-	local a = atom(0)
+	local a, setA = signal(0)
-	local b = atom(0)
+	local b, setB = signal(0)
 
 	listen(a, function()
 		runs += 1
@@ -47,31 +47,31 @@ test("should run in peek", function()
 	assert(runs == 1, "should run once on init")
 	assert(cleanups == 0, "should not cleanup yet")
 
-	a(1)
+	setA(1)
 	assert(runs == 2, "should run on a change")
 	assert(cleanups == 1, "should cleanup first call")
 
-	b(1)
+	setB(1)
 	assert(runs == 2, "should not run on b change")
 	assert(cleanups == 1, "should not cleanup second call")
 end)
 
 test("should run if first value is nil", function()
 	local runs = 0
-	local source = atom(nil :: number?)
+	local source, setSource = signal(nil :: number?)
 
 	listen(source, function()
 		runs += 1
 	end)
 
 	assert(runs == 1, "should run once on init")
-	source(1)
+	setSource(1)
 	assert(runs == 2, "should run once on change")
 end)
 
 test("should track inner subs", function()
 	local order = {}
-	local a = atom(1)
+	local a, setA = signal(1)
 
 	local unsub = listen(a, function()
 		table.insert(order, 1)
@@ -86,22 +86,22 @@ test("should track inner subs", function()
 	assert(table.concat(order) == "123", `bad mount order: {table.concat(order)}`)
 
 	table.clear(order)
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "123", `bad order: {table.concat(order)}`)
 
 	table.clear(order)
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "123", `bad order: {table.concat(order)}`)
 
 	table.clear(order)
 	unsub()
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "", `bad order: {table.concat(order)}`)
 end)
 
 test("should skip redundant updates", function()
 	local order = {}
-	local a = atom(0)
+	local a, setA = signal(0)
 
 	listen(function(): "even" | "odd"
 		return if a() % 2 == 0 then "even" else "odd"
@@ -109,17 +109,17 @@ test("should skip redundant updates", function()
 		table.insert(order, value)
 	end)
 
-	a(1)
+	setA(1)
-	a(3)
+	setA(3)
-	a(4)
+	setA(4)
-	a(6)
+	setA(6)
 	assert(table.concat(order) == "evenoddeven", `bad order: {table.concat(order)}`)
 end)
 
 test("should allow self cleanup", function()
 	local calls = 0
 	local cleanups = 0
-	local a = atom(0)
+	local a, setA = signal(0)
 
 	listen(a, function(_, _, stopEffect)
 		onCleanup(function()
@@ -131,7 +131,7 @@ test("should allow self cleanup", function()
 
 	assert(calls == 1, "should call effect once")
 	assert(cleanups == 1, "should call cleanup once")
-	a(1)
+	setA(1)
 	assert(calls == 1, "should not call effect after a update")
 	assert(cleanups == 1, "should not call cleanup after a update")
 end)

packages/charm/src/__tests__/mapped.spec.luau

@@ -1,25 +1,25 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-local atom = Charm.atom
+local signal = Charm.signal
 local mapped = Charm.mapped
 local test = suite.test
 
-test("should map atom", function()
+test("should map state", function()
-	local src = atom({ 1, 2, 3 })
+	local src, setSrc = signal({ 1, 2, 3 })
 	local map = mapped(src, function(value: number)
 		return value + 1
 	end)
 
 	assert(table.concat(map()) == "234", table.concat(map()))
-	src({ 4, 5, 6 })
+	setSrc({ 4, 5, 6 })
 	assert(table.concat(map()) == "567", table.concat(map()))
 end)
 
 test("should not map unchanged values", function()
 	local calls = 0
 
-	local src = atom({ 1, 2, 3 })
+	local src, setSrc = signal({ 1, 2, 3 })
 	local map = mapped(src, function(value: number)
 		calls += 1
 		return value + 1
@@ -28,11 +28,11 @@ test("should not map unchanged values", function()
 	assert(table.concat(map()) == "234", table.concat(map()))
 	assert(calls == 3, "should map 3 values")
 
-	src({ 1, 3, 3 })
+	setSrc({ 1, 3, 3 })
 	assert(table.concat(map()) == "244", table.concat(map()))
 	assert(calls == 4, "should map 1 change")
 
-	src({})
+	setSrc({})
 	assert(#map() == 0, "should be empty")
 	assert(calls == 4, "should not map for removed values")
 end)
@@ -40,7 +40,7 @@ end)
 test("should not update if no values change", function()
 	local calls = 0
 
-	local src = atom({ 1, 2, 3 })
+	local src, setSrc = signal({ 1, 2, 3 })
 	local map = mapped(src, function(value: number)
 		calls += 1
 		return value + 1
@@ -50,8 +50,8 @@ test("should not update if no values change", function()
 	assert(calls == 3, "should map 3 values")
 	assert(table.concat(map()) == "234", table.concat(map()))
 
-	src({ 4, 5, 6, 7 })
+	setSrc({ 4, 5, 6, 7 })
-	src({ 1, 2, 3 })
+	setSrc({ 1, 2, 3 })
 	map()
 	assert(calls == 3, "should not map unchanged values")
 	assert(table.concat(map()) == "234", table.concat(map()))
@@ -61,7 +61,7 @@ end)
 test("should filter values", function()
 	local calls = 0
 
-	local src = atom({ a = 1, b = 2, c = 3 })
+	local src, setSrc = signal({ a = 1, b = 2, c = 3 })
 	local map = mapped(src, function(value: number)
 		calls += 1
 		return if value < 0 then nil else value
@@ -72,7 +72,7 @@ test("should filter values", function()
 	assert(state.a and state.b and state.c, "should map all values")
 
 	calls = 0
-	src({ a = -1, b = 2, c = 3, d = 4 })
+	setSrc({ a = -1, b = 2, c = 3, d = 4 })
 	state = map()
 	assert(calls == 2, "should map 2 values")
 	assert(state.a == nil, "should remove a")
@@ -83,7 +83,7 @@ end)
 test("should map keys", function()
 	local calls = 0
 
-	local src = atom({ a = 1, b = 2, c = 3 })
+	local src, setSrc = signal({ a = 1, b = 2, c = 3 })
 	local map = mapped(src, function(value: number, key: string)
 		calls += 1
 		return if value < 0 then nil else value, string.upper(key)
@@ -97,7 +97,7 @@ test("should map keys", function()
 	assert(state.C == 3, "should map c")
 
 	calls = 0
-	src({ a = -1, b = 2, c = 3, d = 4 })
+	setSrc({ a = -1, b = 2, c = 3, d = 4 })
 	state = map()
 	assert(calls == 2, "should map 2 values")
 	assert(state.A == nil and state.a == nil, "should remove a")

packages/charm/src/__tests__/observe.spec.luau

@@ -1,14 +1,14 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-local atom = Charm.atom
+local signal = Charm.signal
 local computed = Charm.computed
 local effect = Charm.effect
 local observe = Charm.observe
 local test = suite.test
 
 test("should observe items", function()
-	local items = atom({ 0, 0, 0 })
+	local items, setItems = signal({ 0, 0, 0 })
 	local updates = {}
 	local cleanups = {}
 
@@ -29,18 +29,18 @@ test("should observe items", function()
 	assert(table.concat(updates) == "000", `bad mount: {table.concat(updates)}`)
 
 	table.clear(updates)
-	items({ 1, 2, 3 })
+	setItems({ 1, 2, 3 })
 	assert(table.concat(updates) == "123", `bad update: {table.concat(updates)}`)
 
 	table.clear(updates)
-	items({ 1, 2, nil :: any, 4 })
+	setItems({ 1, 2, nil :: any, 4 })
 	assert(table.concat(updates) == "4", `should add 4: {table.concat(updates)}`)
 	assert(table.concat(cleanups) == "3", `bad cleanup: {table.concat(cleanups)}`)
 end)
 
 test("should dispose scopes", function()
-	local items = atom({ 1, 2, 3 })
+	local items, setItems = signal({ 1, 2, 3 })
-	local a = atom(0)
+	local a, setA = signal(0)
 	local runs = {}
 
 	local dispose = observe(items, function(item)
@@ -51,23 +51,23 @@ test("should dispose scopes", function()
 	end)
 
 	table.clear(runs)
-	items({ 1, 2 })
+	setItems({ 1, 2 })
-	a(1)
+	setA(1)
 	assert(table.concat(runs) == "12", `bad reruns: {table.concat(runs)}`)
 
 	table.clear(runs)
 	dispose()
-	a(2)
+	setA(2)
 	assert(table.concat(runs) == "", `should not rerun: {table.concat(runs)}`)
 end)
 
 test("should queue addition", function()
-	local items = atom({ 1 })
+	local items, setItems = signal({ 1 })
 	local edits = {}
 
 	observe(items, function(item)
-		items({ 1, 2 })
+		setItems({ 1, 2 })
-		items({ 1, 2, 3, 4 })
+		setItems({ 1, 2, 3, 4 })
 		table.insert(edits, `+{item}`)
 		return function()
 			table.insert(edits, `-{item}`)
@@ -78,12 +78,12 @@ test("should queue addition", function()
 end)
 
 test("should queue removal", function()
-	local items = atom({ 1, 2, 3, 4 })
+	local items, setItems = signal({ 1, 2, 3, 4 })
 	local edits = {}
 
 	observe(items, function(item)
-		items({ 1, 2, 3 })
+		setItems({ 1, 2, 3 })
-		items({ 1 })
+		setItems({ 1 })
 		table.insert(edits, `+{item}`)
 		return function()
 			table.insert(edits, `-{item}`)

packages/charm/src/__tests__/peek.spec.luau

@@ -1,14 +1,14 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-local atom = Charm.atom
+local signal = Charm.signal
 local computed = Charm.computed
 local effect = Charm.effect
 local peek = Charm.peek
 local test = suite.test
 
 test("should not run detached", function()
-	local a = atom(1)
+	local a, setA = signal(1)
 	local spyCalls = 0
 
 	effect(function()
@@ -23,15 +23,15 @@ test("should not run detached", function()
 	end)
 
 	assert(spyCalls == 0, "should not be called yet")
-	a(2)
+	setA(2)
 	assert(spyCalls == 1, "should be called once")
-	a(3)
+	setA(3)
 	assert(spyCalls == 2, "should be called twice")
 end)
 
 test("should block tracking inside effects", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
 	local spyCalls = 0
 
 	effect(function()
@@ -42,13 +42,13 @@ test("should block tracking inside effects", function()
 	end)
 	assert(spyCalls == 1, "should be called once")
 
-	a(10)
+	setA(10)
-	b(20)
+	setB(20)
 	assert(spyCalls == 1, "should be called once")
 end)
 
 test("should block tracking even when run inside effect run inside peek", function()
-	local s = atom(1)
+	local s, setS = signal(1)
 	local spyCalls = 0
 
 	peek(function()
@@ -61,32 +61,32 @@ test("should block tracking even when run inside effect run inside peek", functi
 	end)
 	assert(spyCalls == 1, "should be called once")
 
-	s(2)
+	setS(2)
 	assert(spyCalls == 1, "should be called once")
 end)
 
-test("should not cause atom assignments throw", function()
+test("should not cause signal assignments to throw", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local aChangedTime = atom(0)
+	local aChangedTime, setAChangedTime = signal(0)
 
 	local dispose = effect(function()
 		a()
 		peek(function()
-			aChangedTime(aChangedTime() + 1)
+			setAChangedTime(aChangedTime() + 1)
 		end)
 	end)
 
-	a(2)
+	setA(2)
 	assert(aChangedTime() == 2, "aChangedTime should be 2")
-	a(3)
+	setA(3)
 	assert(aChangedTime() == 3, "aChangedTime should be 3")
 
 	dispose()
 end)
 
-test("should block tracking inside computed atoms", function()
+test("should block tracking inside computed signals", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
 	local spyCalls = 0
 	local c = computed(function()
 		return peek(function()
@@ -97,18 +97,18 @@ test("should block tracking inside computed atoms", function()
 
 	assert(spyCalls == 0, "should not be called yet")
 	assert(c() == 3, "c should be 3")
-	a(10)
+	setA(10)
 	c()
-	b(20)
+	setB(20)
 	c()
 	assert(spyCalls == 1, "should be called once")
 	assert(c() == 3, "c should be 3")
 end)
 
 test("should track outside peek", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
-	local c = atom(3)
+	local c, setC = signal(3)
 	local spyCalls = 0
 
 	effect(function()
@@ -119,16 +119,16 @@ test("should track outside peek", function()
 	end)
 
 	assert(spyCalls == 1, "should be called once")
-	a(10)
+	setA(10)
 	assert(spyCalls == 2, "should be called twice")
-	b(20)
+	setB(20)
 	assert(spyCalls == 3, "should be called three times")
-	c(30)
+	setC(30)
 	assert(spyCalls == 3, "should not run on c change")
 end)
 
 test("should stack peek", function()
-	local a = atom(1)
+	local a, setA = signal(1)
 	local spyCalls = 0
 
 	effect(function()
@@ -140,7 +140,7 @@ test("should stack peek", function()
 	end)
 
 	assert(spyCalls == 1, "should be called once")
-	a(2)
+	setA(2)
 	assert(spyCalls == 1, "should not be called twice")
 end)
 

packages/charm/src/__tests__/subscribe.spec.luau

@@ -1,9 +1,7 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-type Atom<T> = Charm.Atom<T>
+local signal = Charm.signal
-
-local atom = Charm.atom
 local computed = Charm.computed
 local subscribe = Charm.subscribe
 local listen = Charm.listen
@@ -11,7 +9,7 @@ local effect = Charm.effect
 local test = suite.test
 
 test("should subscribe to selector", function()
-	local source = atom(0)
+	local source, setSource = signal(0)
 	local current, previous
 
 	local unsub = subscribe(function()
@@ -22,20 +20,20 @@ test("should subscribe to selector", function()
 	end)
 
 	assert(not current and not previous, "should not run initially")
-	source(0)
+	setSource(0)
 	assert(not current and not previous, "should skip redundant update")
-	source(1)
+	setSource(1)
 	assert(current == 2 and previous == 1, "should run with new value")
 	unsub()
-	source(2)
+	setSource(2)
 	assert(current == 2 and previous == 1, "should not run after unsub")
 end)
 
 test("should run in peek", function()
 	local runs = 0
 	local cleanups = 0
-	local a = atom(0)
+	local a, setA = signal(0)
-	local b = atom(0)
+	local b, setB = signal(0)
 
 	subscribe(a, function()
 		runs += 1
@@ -50,30 +48,30 @@ test("should run in peek", function()
 	assert(runs == 0, "should not run once on init")
 	assert(cleanups == 0, "should not cleanup yet")
 
-	a(1)
+	setA(1)
 	assert(runs == 1, "should run once on change")
 	assert(cleanups == 0, "should not cleanup yet")
 
-	b(1)
+	setB(1)
 	assert(runs == 1, "should not run on b change")
 	assert(cleanups == 0, "should not cleanup first call")
 
-	a(2)
+	setA(2)
 	assert(runs == 2, "should run on a change")
 	assert(cleanups == 1, "should cleanup first call")
 end)
 
 test("should ensure correct execution order", function()
 	local order = {}
-	local n1 = atom(0)
+	local n1, setN1 = signal(0)
-	local n2 = atom(0)
+	local n2, setN2 = signal(0)
 	local sum = computed(function()
 		return n1() + n2()
 	end)
 
 	subscribe(n1, function()
 		table.insert(order, 1)
-		n2(n2() + 1)
+		setN2(n2() + 1)
 	end)
 
 	subscribe(sum, function()
@@ -84,14 +82,14 @@ test("should ensure correct execution order", function()
 		table.insert(order, 3)
 	end)
 
-	n1(n1() + 1)
+	setN1(n1() + 1)
 
 	assert(table.concat(order) == "123", `bad order: {table.concat(order)}`)
 end)
 
 test("should track inner subs", function()
 	local order = {}
-	local a = atom(1)
+	local a, setA = signal(1)
 
 	local unsub = subscribe(a, function()
 		table.insert(order, 1)
@@ -103,22 +101,22 @@ test("should track inner subs", function()
 		end)
 	end)
 
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "123", `bad order: {table.concat(order)}`)
 
 	table.clear(order)
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "123", `bad order: {table.concat(order)}`)
 
 	table.clear(order)
 	unsub()
-	a(a() + 1)
+	setA(a() + 1)
 	assert(table.concat(order) == "", `bad order: {table.concat(order)}`)
 end)
 
 test("should skip redundant updates", function()
 	local order = {}
-	local a = atom(0)
+	local a, setA = signal(0)
 
 	subscribe(function(): "even" | "odd"
 		return if a() % 2 == 0 then "even" else "odd"
@@ -126,10 +124,10 @@ test("should skip redundant updates", function()
 		table.insert(order, value)
 	end)
 
-	a(1)
+	setA(1)
-	a(3)
+	setA(3)
-	a(4)
+	setA(4)
-	a(6)
+	setA(6)
 	assert(table.concat(order) == "oddeven", `bad order: {table.concat(order)}`)
 end)
 

packages/charm/src/__tests__/untracked.spec.luau

@@ -1,7 +1,7 @@
 local Charm = require("../")
 local suite = require("../../../../test/suite")
 
-local atom = Charm.atom
+local signal = Charm.signal
 local computed = Charm.computed
 local effect = Charm.effect
 local effectScope = Charm.effectScope
@@ -9,7 +9,7 @@ local untracked = Charm.untracked
 local test = suite.test
 
 test("should run detached from effect", function()
-	local a = atom(1)
+	local a, setA = signal(1)
 	local effects = 0
 	local innerEffects = {}
 
@@ -27,7 +27,7 @@ test("should run detached from effect", function()
 	end)
 
 	assert(effects == 1, "should have one effect")
-	a(2)
+	setA(2)
 	assert(effects == 2, "should have two effects")
 	stopEffect()
 	assert(effects == 2, "should still have two effects")
@@ -60,8 +60,8 @@ test("should run detached from effect scope", function()
 end)
 
 test("should block tracking inside effects", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
 	local spyCalls = 0
 
 	effect(function()
@@ -72,13 +72,13 @@ test("should block tracking inside effects", function()
 	end)
 	assert(spyCalls == 1, "should be called once")
 
-	a(10)
+	setA(10)
-	b(20)
+	setB(20)
 	assert(spyCalls == 1, "should be called once")
 end)
 
 test("should block tracking even when run inside effect run inside untracked", function()
-	local s = atom(1)
+	local s, setS = signal(1)
 	local spyCalls = 0
 
 	untracked(function()
@@ -91,32 +91,32 @@ test("should block tracking even when run inside effect run inside untracked", f
 	end)
 	assert(spyCalls == 1, "should be called once")
 
-	s(2)
+	setS(2)
 	assert(spyCalls == 1, "should be called once")
 end)
 
-test("should not cause atom assignments throw", function()
+test("should not cause signal assignments to throw", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local aChangedTime = atom(0)
+	local aChangedTime, setAChangedTime = signal(0)
 
 	local dispose = effect(function()
 		a()
 		untracked(function()
-			aChangedTime(aChangedTime() + 1)
+			setAChangedTime(aChangedTime() + 1)
 		end)
 	end)
 
-	a(2)
+	setA(2)
 	assert(aChangedTime() == 2, "aChangedTime should be 2")
-	a(3)
+	setA(3)
 	assert(aChangedTime() == 3, "aChangedTime should be 3")
 
 	dispose()
 end)
 
-test("should block tracking inside computed atoms", function()
+test("should block tracking inside computed signals", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
 	local spyCalls = 0
 	local c = computed(function()
 		return untracked(function()
@@ -127,18 +127,18 @@ test("should block tracking inside computed atoms", function()
 
 	assert(spyCalls == 0, "should not be called yet")
 	assert(c() == 3, "c should be 3")
-	a(10)
+	setA(10)
 	c()
-	b(20)
+	setB(20)
 	c()
 	assert(spyCalls == 1, "should be called once")
 	assert(c() == 3, "c should be 3")
 end)
 
 test("should track outside untracked", function()
-	local a = atom(1)
+	local a, setA = signal(1)
-	local b = atom(2)
+	local b, setB = signal(2)
-	local c = atom(3)
+	local c, setC = signal(3)
 	local spyCalls = 0
 
 	effect(function()
@@ -149,16 +149,16 @@ test("should track outside untracked", function()
 	end)
 
 	assert(spyCalls == 1, "should be called once")
-	a(10)
+	setA(10)
 	assert(spyCalls == 2, "should be called twice")
-	b(20)
+	setB(20)
 	assert(spyCalls == 3, "should be called three times")
-	c(30)
+	setC(30)
 	assert(spyCalls == 3, "should not run on c change")
 end)
 
 test("should stack untracked", function()
-	local a = atom(1)
+	local a, setA = signal(1)
 	local spyCalls = 0
 
 	effect(function()
@@ -170,7 +170,7 @@ test("should stack untracked", function()
 	end)
 
 	assert(spyCalls == 1, "should be called once")
-	a(2)
+	setA(2)
 	assert(spyCalls == 1, "should not be called twice")
 end)
 

packages/charm/src/alien.luau

@@ -1,3 +1,30 @@
+--[[
+	Reactive system adapted from alien-signals at
+	https://github.com/stackblitz/alien-signals/blob/master/src/system.ts
+
+	MIT License
+
+	Copyright (c) 2024-present Johnson Chu
+
+	Permission is hereby granted, free of charge, to any person obtaining a copy
+	of this software and associated documentation files (the "Software"), to deal
+	in the Software without restriction, including without limitation the rights
+	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	copies of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+]]
+
 export type ReactiveNode = {
 	deps: Link?,
 	depsTail: Link?,
@@ -23,14 +50,14 @@ type Stack<T> = {
 
 export type ReactiveFlags = number
 
-local NONE = 0b00000000
+local NONE = 0b0000000
-local MUTABLE = 0b00000001
+local MUTABLE = 0b0000001
-local WATCHING = 0b00000010
+local WATCHING = 0b0000010
-local RECURSED_CHECK = 0b00000100
+local RECURSED_CHECK = 0b0000100
-local RECURSED = 0b00001000
+local RECURSED = 0b0001000
-local DIRTY = 0b00010000
+local DIRTY = 0b0010000
-local PENDING = 0b00100000
+local PENDING = 0b0100000
-local PEEKING = 0b10000000
+local PEEKING = 0b1000000
 
 local ReactiveFlags = {
 	None = NONE,

packages/charm/src/core.luau

@@ -11,14 +11,40 @@ local createReactiveSystem = alien.createReactiveSystem
 local deepFreeze = utils.deepFreeze
 local noYield = utils.noYield
 
-local NONE = 0b00000000
+--[[
-local MUTABLE = 0b00000001
+	Reactive system adapted from alien-signals at
-local WATCHING = 0b00000010
+	https://github.com/stackblitz/alien-signals/blob/master/src/index.ts
-local RECURSED_CHECK = 0b00000100
+
-local DIRTY = 0b00010000
+	MIT License
-local PENDING = 0b00100000
+
-local QUEUED = 0b01000000
+	Copyright (c) 2024-present Johnson Chu
-local PEEKING = 0b10000000
+
+	Permission is hereby granted, free of charge, to any person obtaining a copy
+	of this software and associated documentation files (the "Software"), to deal
+	in the Software without restriction, including without limitation the rights
+	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	copies of the Software, and to permit persons to whom the Software is
+	furnished to do so, subject to the following conditions:
+
+	The above copyright notice and this permission notice shall be included in all
+	copies or substantial portions of the Software.
+
+	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	SOFTWARE.
+]]
+
+local NONE = 0b0000000
+local MUTABLE = 0b0000001
+local WATCHING = 0b0000010
+local RECURSED_CHECK = 0b0000100
+local DIRTY = 0b0010000
+local PENDING = 0b0100000
+local PEEKING = 0b1000000
 
 type EffectScope = ReactiveNode & {
 	cleanups: { () -> () },
@@ -49,8 +75,8 @@ local shallowPropagate: (link: Link) -> ()
 local cycle = 0
 local batchDepth = 0
 local notifyIndex = 0
-local queuedEffects: { Effect | EffectScope? } = {}
+local queued: { Effect? } = {}
-local queuedEffectsLength = 0
+local queuedLength = 0
 local activeSub: ReactiveNode?
 
 local function getActiveSub(): ReactiveNode?
@@ -83,15 +109,9 @@ local function runCleanups(effect: EffectScope)
 	table.clear(effect.cleanups)
 end
 
-local function setNotPending(sub: ReactiveNode, flags: ReactiveFlags)
+local function run(e: Effect): ()
-	sub.flags = bit32.band(flags, bit32.bnot(PENDING))
+	local flags = e.flags
-end
+	if bit32.btest(flags, DIRTY) or (bit32.btest(flags, PENDING) and checkDirty(e.deps :: Link, e)) then
-
-local function run(e: Effect, flags: ReactiveFlags): ()
-	if
-		bit32.btest(flags, DIRTY)
-		or (bit32.btest(flags, PENDING) and (checkDirty(e.deps :: Link, e) or setNotPending(e, flags)))
-	then
 		runCleanups(e)
 		cycle += 1
 		e.depsTail = nil
@@ -107,30 +127,19 @@ local function run(e: Effect, flags: ReactiveFlags): ()
 			table.insert(e.cleanups, result)
 		end
 	else
-		local link = e.deps
+		e.flags = WATCHING
-		while link do
-			local dep = link.dep
-			local depFlags = dep.flags
-			if bit32.btest(depFlags, QUEUED) then
-				depFlags = bit32.band(depFlags, bit32.bnot(QUEUED))
-				dep.flags = depFlags
-				run(dep :: Effect, depFlags)
-			end
-			link = link.nextDep
-		end
 	end
 end
 
 local function flush(): ()
-	while notifyIndex < queuedEffectsLength do
+	while notifyIndex < queuedLength do
+		local effect = queued[notifyIndex] :: Effect
+		queued[notifyIndex] = nil
 		notifyIndex += 1
-		local effect = queuedEffects[notifyIndex] :: Effect
+		run(effect)
-		queuedEffects[notifyIndex] = nil
-		effect.flags = bit32.band(effect.flags, bit32.bnot(QUEUED))
-		run(effect, effect.flags)
 	end
 	notifyIndex = 0
-	queuedEffectsLength = 0
+	queuedLength = 0
 end
 
 local function getBatchDepth(): number
@@ -183,6 +192,10 @@ local function updateSignal(s: Signal): boolean
 	end
 end
 
+local function setNotPending(sub: ReactiveNode, flags: ReactiveFlags)
+	sub.flags = bit32.band(flags, bit32.bnot(PENDING))
+end
+
 local function computedOper<T>(this: Computed<T>): () -> T
 	return function(): T
 		local flags = this.flags
@@ -196,6 +209,16 @@ local function computedOper<T>(this: Computed<T>): () -> T
 					shallowPropagate(subs)
 				end
 			end
+		elseif flags == NONE then
+			this.flags = MUTABLE
+			local prevSub = setActiveSub(this)
+			local success, result = pcall(this.getter)
+			activeSub = prevSub
+			if success then
+				this.value = result
+			else
+				error(result)
+			end
 		end
 		if activeSub then
 			link(this, activeSub, cycle)
@@ -332,7 +355,7 @@ end
 --- @see https://github.com/littensy/charm?tab=readme-ov-file#computedgetter
 local function computed<T>(getter: (previousValue: T?) -> T): () -> T
 	return computedOper({
-		flags = bit32.bor(MUTABLE, DIRTY),
+		flags = NONE,
 		getter = getter,
 	})
 end
@@ -536,30 +559,40 @@ local function listen<T>(getter: () -> T, callback: (state: T, previous: T?, dis
 	return dispose
 end
 
-local function notify(e: ReactiveNode)
-	local flags = e.flags
-	if not bit32.btest(flags, QUEUED) then
-		e.flags = bit32.bor(flags, QUEUED)
-		local subs = e.subs
-		if subs then
-			notify(subs.sub)
-		else
-			queuedEffectsLength += 1
-			queuedEffects[queuedEffectsLength] = e :: Effect
-		end
-	end
-end
-
 local reactiveSystem = createReactiveSystem({
-	update = function(node: ReactiveNode): boolean
+	update = function(node)
 		if node.depsTail then
 			return updateComputed(node :: Computed)
 		else
 			return updateSignal(node :: Signal)
 		end
 	end,
-	notify = notify,
+	notify = function(effect)
-	unwatched = function(node: ReactiveNode)
+		local insertIndex = queuedLength
+		local firstInsertedIndex = insertIndex
+
+		repeat
+			effect.flags = bit32.band(effect.flags, bit32.bnot(WATCHING))
+			queued[insertIndex] = effect :: Effect
+			insertIndex += 1
+			effect = (effect.subs and effect.subs.sub) :: Effect
+			if not effect or bit32.band(effect.flags, WATCHING) == 0 then
+				break
+			end
+		until false
+
+		queuedLength = insertIndex
+
+		insertIndex -= 1
+		while firstInsertedIndex < insertIndex do
+			local left = queued[firstInsertedIndex]
+			queued[firstInsertedIndex] = queued[insertIndex]
+			queued[insertIndex] = left
+			firstInsertedIndex += 1
+			insertIndex -= 1
+		end
+	end,
+	unwatched = function(node)
 		if bit32.band(node.flags, MUTABLE) == 0 then
 			effectScopeOper(node :: EffectScope)()
 		elseif node.depsTail then

packages/charm/src/utils.luau

@@ -1,10 +1,10 @@
-local function noYieldHandler(thread: thread, ok: boolean, ...)
+local function noYieldHandler(thread: thread, ok: boolean, ...): (boolean, ...any)
-	if not ok then
+	if ok and coroutine.status(thread) == "dead" then
-		return false, debug.traceback(thread, tostring((...)))
-	elseif coroutine.status(thread) ~= "dead" then
-		return false, debug.traceback(thread, "Attempted to yield!")
-	else
 		return true, ...
+	elseif not ok then
+		return false, debug.traceback(thread, tostring((...)))
+	else
+		return false, debug.traceback(thread, "Attempted to yield!")
 	end
 end
 

rokit.toml

@@ -5,9 +5,9 @@
 
 [tools]
 wally = "UpliftGames/wally@0.3.2"
-rojo = "rojo-rbx/rojo@7.5.1"
+rojo = "rojo-rbx/rojo@7.6.0"
-stylua = "johnnymorganz/stylua@2.2.0"
+stylua = "johnnymorganz/stylua@2.3.0"
 selene = "Kampfkarren/selene@0.29.0"
-luau-lsp = "johnnymorganz/luau-lsp@1.53.5"
+luau-lsp = "johnnymorganz/luau-lsp@1.55.0"
-lune = "lune-org/lune@0.10.2"
+lune = "lune-org/lune@0.10.4"
 lute = "luau-lang/lute@0.1.0-nightly.20250923"