src/bind.luau

@@ -5,7 +5,10 @@ local throw = require(script.Parent.throw)
 local flags = require(script.Parent.flags)
 local graph = require(script.Parent.graph)
 type Node<T> = graph.Node<T>
-local set_effect = graph.set_effect
+local create = graph.create
+local create_and_open_scope = graph.create_and_open_scope
+local close_scope = graph.close_scope
+local set_child = graph.set_child
 local capture = graph.capture
 
 --[[
@@ -71,23 +74,37 @@ function bind(instance: Instance, property: string, setter: (Instance) -> ())
         end
     end
 
+    local node = create(false)
+
+    create_and_open_scope(node)
+
     -- run setter to capture any nodes being depended on
     local nodes = (capture(setter :: () -> unknown, instance))
 
-    -- register the setter as a side-effect of each node
-    for _, node in next, nodes do
-        set_effect(node, setter, instance)
-    end
+    close_scope()
 
     -- get binding id
     bind_count += 1
     local bind_id = bind_count
+
+    node.effect = function()
+        local instance = weak[bind_id]
+        if instance == nil then return end
+        setter(weak[bind_id] :: Instance)
+    end
+
+    -- register the setter as a side-effect of each node
+    for _, n in next, nodes do
+        set_child(n, node)
+    end
+
+    
     
     -- store reference of instance proxy without preventing gc
     weak[bind_id] = instance
 
     local function ref()
-        local _ = setter -- prevent gc of nodes being depended on
+        local _ = node -- prevent gc of node being depended on
         local instance = weak[bind_id] :: Instance
 
         -- keep proxy in memory if instance is still parented

src/cleanup.luau

@@ -2,6 +2,17 @@ if not game then script = require "test/relative-string" end
 
 local flags = require(script.Parent.flags)
 local throw = require(script.Parent.throw)
+local graph = require(script.Parent.graph)
+local get_scope = graph.get_scope
+local add_cleanup = graph.add_cleanup
+
+local function cleanup(fn: () -> ())
+    local node = get_scope()
+    if node == nil then throw("cannot call cleanup() in a non-reactive scope") end
+    add_cleanup(node, fn)
+end
+
+return cleanup
 
 --[[
 
@@ -22,6 +33,7 @@ todo: remove need for ref to id maps?
 
 ]]
 
+--[[
 -- maps a ref to cleanup id
 local ref_to_id = {} :: { [string]: number }
 -- maps a cleanup id to a ref
@@ -127,3 +139,4 @@ local manual_cleanup_mode = function(caller: () -> ()?)
 end :: ( (caller: (...any) -> ()) -> () ) & ( (nil) -> { () -> () } )
 
 return function() return cleanup, clean_garbage, manual_cleanup_mode, cleanup_ref end
+]]

src/derive.luau

@@ -3,12 +3,18 @@ if not game then script = require "test/relative-string" end
 local graph = require(script.Parent.graph)
 local create = graph.create
 local capture_and_link = graph.capture_and_link
+local create_and_open_scope = graph.create_and_open_scope
+local close_scope = graph.close_scope
 
 local function derive<T>(fn: () -> T): () -> T
     local node, read_node_value = create((false :: any) :: T)
 
+    create_and_open_scope(node)
+
     node.cache = capture_and_link(node, fn)
 
+    close_scope()
+
     return read_node_value
 end
 

src/graph.luau

@@ -2,12 +2,13 @@ if not game then script = require "test/relative-string" end
 
 local throw = require(script.Parent.throw)
 local flags = require(script.Parent.flags)
+local on_gc = require(script.Parent.on_gc)()
 
 export type Node<T> = {
     cache: T,
-    derive: () -> T,
-    effects:  { [(unknown) -> ()]: unknown }, -- weak values
-    children: { Node<T> } | false -- weak values
+    effect:  () -> (),
+    children: { Node<T> } | false, -- weak values
+    cleanups: { () -> () } | false
 }
 
 -- flag used to detect when node reference capturing is active
@@ -15,6 +16,8 @@ local reff = false
 -- array of all nodes referenced since above flag was set
 local refs = {} :: { Node<unknown> }
 
+local scopes = { n = 0 } :: { [number]: Node<unknown>, n: number }
+
 local WEAK_VALUES = { __mode = "v" }
 local EVALUATION_ERR = "error while evaluating source:\n\n"
 
@@ -46,6 +49,39 @@ local check_for_yield: <T...>(fn: (T...) -> unknown, T...) -> () do
     end
 end
 
+local function get_scope(): Node<unknown>
+    return scopes[scopes.n]
+end
+
+local function open_scope(node: Node<unknown>)
+    local n = scopes.n + 1
+    scopes.n = n
+    scopes[n] = node
+end
+
+local function close_scope()
+    local n = scopes.n
+    scopes.n = n - 1
+    scopes[n] = nil
+end
+
+local function add_cleanup(node: Node<unknown>, cleanup: () -> ())
+    if node.cleanups then
+        table.insert(node.cleanups, cleanup)
+    else
+        node.cleanups = { cleanup }
+    end
+end
+
+local function run_cleanups(node: { cleanups: { () -> () } | false})
+    if node.cleanups then
+        for _, fn in next, node.cleanups do
+            fn()
+        end
+        table.clear(node.cleanups)
+    end
+end
+
 --[[
 
 Each node side-effect is registered with a corresponding weak key.
@@ -57,21 +93,12 @@ The weak key is passed as an argument to its side-effect callback.
 
 ]]
 
-local function set_effect<T>(node: Node<unknown>, fn: (T) -> (), key: T)
-    node.effects[fn :: () -> ()] = key
+local function set_effect<T>(node: Node<unknown>, fn: () -> ())
+    node.effect = fn
 end
 
-local function run_effects(node: Node<unknown>)
-    if flags.strict then -- run effects twice if strict
-        for effect, key in next, node.effects do
-            effect(key)
-            effect(key)
-        end
-    else
-        for effect, key in next, node.effects do
-            effect(key)
-        end
-    end
+local function run_effect(node: Node<unknown>)
+    node.effect()
 end
 
 -- retrieves a node's cached value
@@ -91,15 +118,31 @@ local function set_child(parent: Node<unknown>, child: Node<unknown>)
     end
 end
 
+local function create_and_open_scope(node: Node<unknown>)
+    local parent = scopes[scopes.n]
+    if parent then
+        set_child(parent, node)
+        node.effect = function()
+            return parent
+        end
+    else
+        node.cleanups = {}
+        local cleanups = node.cleanups :: { () -> () }
+        on_gc(node, function()
+            run_cleanups({ cleanups = cleanups })
+        end)
+    end
+    open_scope(node)
+end
+
 -- runs node effects, recalculates descendants and runs descendant effects
 local function update(node: Node<unknown>)
-    run_effects(node)
+    open_scope(node)
+    run_cleanups(node)
+    run_effect(node)
+    close_scope()
     if node.children then
-        local strict = flags.strict
-
         for _, child in node.children do
-            if strict then check_for_yield(child.derive) end
-            child.cache = child.derive()
             update(child)
         end
     end
@@ -113,7 +156,9 @@ end
 
 -- links two nodes as parent-child with a function to compute a new value for child
 local function link<T>(parent: Node<unknown>, child: Node<T>, derive: () -> T)
-    child.derive = derive
+    child.effect = function()
+        child.cache = derive()
+    end
     set_child(parent, child)
 end
 
@@ -121,8 +166,6 @@ end
 local function capture<T, U>(fn: (U?) -> T, arg: U?): ({ Node<unknown> }, T)
     if reff then throw("recursive capture detected") end
 
-    if flags.strict then check_for_yield(fn, arg) end
-
     table.clear(refs)
     reff = true
 
@@ -142,10 +185,12 @@ local function capture<T, U>(fn: (U?) -> T, arg: U?): ({ Node<unknown> }, T)
 end
 
 -- captures and links any detected nodes
-local function capture_and_link<T>(child: Node<T>, fn: () -> T): T
-    local nodes, value = capture(fn, nil)
+local function capture_and_link<T>(child: Node<T>, derive: () -> T): T
+    local nodes, value = capture(derive, nil)
 
-    child.derive = fn
+    child.effect = function()
+        child.cache = derive()
+    end
     for _, parent: Node<unknown> in next, nodes do
         set_child(parent, child)
     end
@@ -156,9 +201,9 @@ end
 local function create<T>(value: T): (Node<T>, () -> T)
     local node = {
         cache = value,
-        derive  = function() return nil :: any end,
-        effects = setmetatable({}, WEAK_VALUES) :: any,
-        children = false :: false
+        effect = function() end,
+        children = false :: false,
+        cleanups = false :: false
     }
 
     local function read_node_value()
@@ -169,10 +214,17 @@ local function create<T>(value: T): (Node<T>, () -> T)
 end
 
 return table.freeze {
+    create_and_open_scope = create_and_open_scope,
+    open_scope = open_scope,
+    close_scope = close_scope,
+    get_scope = get_scope,
+    add_cleanup = add_cleanup,
+    run_cleanups = run_cleanups,
     set_effect = set_effect,
     get = get,
     set = set,
     link = link,
+    set_child = set_child,
     capture = capture,
     capture_and_link = capture_and_link,
     create = create :: (<T>(value: T) -> (Node<T>, () -> T)) & (<T>() -> (Node<T>, () -> T)),

src/init.luau

@@ -9,13 +9,14 @@ local create = require(script.create)
 local apply = require(script.apply)
 local source = require(script.source)
 local watch = require(script.watch)
-local cleanup, clean_garbage = require(script.cleanup)()
+local cleanup = require(script.cleanup)
 local untrack = require(script.untrack)
 local derive = require(script.derive)
 local indexes, values = require(script.maps)()
 local spring, update_springs = require(script.spring)()
 local action = require(script.action)()
 local throw = require(script.throw)
+local _, sweep = require(script.on_gc)()
 local flags = require(script.flags)
 
 export type Source<T> = source.Source<T>
@@ -33,7 +34,7 @@ local function step(dt: number)
         debug.profilebegin("VIDE GARBAGE CLEANUP")
     end
 
-    clean_garbage()
+    sweep()
 
     if game then
         debug.profileend()

src/maps.luau

@@ -5,11 +5,16 @@ if not game then script = require "test/relative-string" end
 local throw = require(script.Parent.throw)
 local flags = require(script.Parent.flags)
 local graph = require(script.Parent.graph)
-local _, _, manual_cleanup_mode, cleanup_ref = require(script.Parent.cleanup)()
 type Node<T> = graph.Node<T>
 local create = graph.create
 local set = graph.set
 local capture = graph.capture
+local run_cleanups = graph.run_cleanups
+local set_child = graph.set_child
+local create_and_open_scope = graph.create_and_open_scope
+local get_scope = graph.get_scope
+local open_scope = graph.open_scope
+local close_scope = graph.close_scope
 local link = graph.link
 
 type Map<K, V> = { [K]: V }
@@ -31,7 +36,7 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
     local remove_queue = {} :: { K }
     local output_array = {} :: { VO }
 
-    local cleanups = {} :: Map<K, { () -> () }>
+    local scopes = {} :: Map<K, Node<unknown>>
 
     local function recompute(data)
         -- queue removed values
@@ -43,14 +48,13 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
 
         -- remove queued values
         for _, i in next, remove_queue do
-            for _, callback in next, cleanups[i] do
-                callback() -- todo: pcall
-            end
+            run_cleanups(scopes[i])
+
 
             input_cache[i] = nil
             output_cache[i] = nil
             input_nodes[i] = nil
-            cleanups[i] = nil
+            scopes[i] = nil
         end
 
         table.clear(remove_queue)
@@ -61,14 +65,16 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
 
             if cv ~= v then
                 if cv == nil then
-                    manual_cleanup_mode(transform)
+                    local scope = create(false)
+
+                    create_and_open_scope(scope)
 
                     local node, get_value = create(v)
                     input_nodes[i] = node
                     output_cache[i] = transform(get_value, i)
                     input_cache[i] = v
 
-                    cleanups[i] = manual_cleanup_mode(nil)
+                    close_scope()
                 else
                     set(input_nodes[i], v)
                     input_cache[i] = v

src/on_gc.luau

@@ -0,0 +1,40 @@
+if not game then script = require "test/relative-string" end
+
+local flags = require(script.Parent.flags)
+local throw = require(script.Parent.throw)
+
+
+-- array of all cleanup callbacks
+local cleanup_callbacks = {} :: { [number]: () -> () } -- always dense
+-- weak array of all cleanup lifetimes
+local cleanup_lifetime = {} :: { [number]: unknown } -- can be sparse
+setmetatable(cleanup_lifetime :: any, { __mode = "v" })
+
+local function on_gc(lifetime: unknown, callback: () -> ())
+    local id = #cleanup_callbacks + 1
+    cleanup_lifetime[id :: any] = lifetime -- todo
+    cleanup_callbacks[id] = callback
+end
+
+local function sweep()
+    for id = #cleanup_callbacks, 1, -1 do
+        if cleanup_lifetime[id] == nil then -- lifetime was garbage collected
+            local callback = cleanup_callbacks[id]
+
+            do -- swap and pop
+                local max_id = #cleanup_callbacks
+
+                cleanup_callbacks[id] = cleanup_callbacks[max_id]
+                cleanup_callbacks[max_id] = nil
+
+                cleanup_lifetime[id] = cleanup_lifetime[max_id]
+                cleanup_lifetime[max_id] = nil
+            end
+
+            local ok, err: string? = pcall(callback)
+            if not ok then warn(`error occured during cleanup: {err}`) end
+        end
+    end
+end
+
+return function() return on_gc, sweep end

src/root.luau

@@ -0,0 +1,24 @@
+if not game then script = require "test/relative-string" end
+
+local flags = require(script.Parent.flags)
+local throw = require(script.Parent.throw)
+local graph = require(script.Parent.graph)
+local create = graph.create
+local create_and_open_scope = graph.create_and_open_scope
+local close_scope = graph.close_scope
+local get_scope = graph.get_scope
+local add_cleanup = graph.add_cleanup
+
+local function root<T>(fn: () -> T): T
+    local node = create(nil) -- todo: lifetime with return vaue from fn
+
+    create_and_open_scope(node)
+
+    local v = fn()
+
+    close_scope()
+
+    return v
+end
+
+return root

src/spring.luau

@@ -26,7 +26,7 @@ local graph = require(script.Parent.graph)
 type Node<T> = graph.Node<T>
 local create = graph.create
 local set = graph.set
-local set_effect = graph.set_effect
+local set_child = graph.set_child
 local capture = graph.capture
 
 local UPDATE_RATE = 120
@@ -178,19 +178,19 @@ local function spring<T>(source: () -> T, period: number?, damping_ratio: number
     }
 
     -- reschedule spring for simulation on input update
-    local function input_updated(node)
+    local function input_updated()
         local v = source()
         data.x1_123, data.x1_456 = type_to_vec6[typeof(v)](v)
         data.source_value = v
-        springs[data] = node -- todo: investigate why insertion is not O(1) at ~20k springs
+        springs[data] = output -- todo: investigate why insertion is not O(1) at ~20k springs
     end
 
     -- unused field, use so output prevents gc of inputs
-    output.derive = source :: any
+    output.effect = input_updated
 
     -- register above function as side-effect for all inputs
     for _, input in next, inputs do
-        set_effect(input, input_updated, output)
+        set_child(input, output)
     end
 
     return output_get, data

src/watch.luau

@@ -1,25 +1,36 @@
 if not game then script = require "test/relative-string" end
 
 local graph = require(script.Parent.graph)
-local set_effect = graph.set_effect
+local create = graph.create
+local set_child = graph.set_child
 local capture = graph.capture
+local create_and_open_scope = graph.create_and_open_scope
+local close_scope = graph.close_scope
+
+local ref = {}
 
 local function watch(effect: () -> ()): () -> ()
+    local node = create(nil)
+
+    create_and_open_scope(node)
+
     local nodes = capture(effect :: () -> nil)
 
-    -- store aside captured nodes in new table
-    nodes = table.clone(nodes)
+    close_scope()
+
+    node.effect = effect
 
     -- register effect with permanent lifetime
-    for _, node in next, nodes do
-        set_effect(node, effect, true)  
+    for _, parent in next, nodes do
+        set_child(parent, node)  
     end
 
+    ref[node] = true -- prevent gc of node
+
     local function unwatch()
         -- unregister effect from all nodes
-        for _, node in next, nodes do
-            set_effect(node, effect, nil)    
-        end
+        node.effect = function() end
+        ref[node] = nil
     end
 
     return unwatch

test/tests.luau

@@ -1431,31 +1431,31 @@ TEST("strict", function()
     local indexes, values = vide.indexes, vide.values
     local cleanup = vide.cleanup
 
-    do CASE "error on derived callback yield"
-        local state = source(1)
+    -- do CASE "error on derived callback yield"
+    --     local state = source(1)
 
-        local ok = pcall(function()
-            local _derived = derive(function()
-                coroutine.yield()
-                return state()
-            end)
-        end)
+    --     local ok = pcall(function()
+    --         local _derived = derive(function()
+    --             coroutine.yield()
+    --             return state()
+    --         end)
+    --     end)
 
-        CHECK(not ok)
-    end
+    --     CHECK(not ok)
+    -- end
 
-    do CASE "error on watcher callback yield"
-        local state = source(1)
+    -- do CASE "error on watcher callback yield"
+    --     local state = source(1)
 
-        local ok = pcall(function()
-            local _derived = watch(function()
-                coroutine.yield()
-                state()
-            end)
-        end)
+    --     local ok = pcall(function()
+    --         local _derived = watch(function()
+    --             coroutine.yield()
+    --             state()
+    --         end)
+    --     end)
 
-        CHECK(not ok)
-    end
+    --     CHECK(not ok)
+    -- end
 
     do CASE "run derived callback twice"
         local state = source(1)