src/bind.luau

@@ -6,9 +6,9 @@ local flags = require(script.Parent.flags)
 local graph = require(script.Parent.graph)
 type Node<T> = graph.Node<T>
 local create = graph.create
-local create_and_open_scope = graph.create_and_open_scope
+local init_scope = graph.init_scope
 local close_scope = graph.close_scope
-local set_child = graph.set_child
+local add_child = graph.add_child
 local capture = graph.capture
 
 --[[
@@ -29,14 +29,7 @@ todo: investigate behavior in case B is parented to A, and A has no parent or re
 
 ]]
 
--- holds parented instance proxies in memory
-local hold: { Instance? } = {} 
 
--- weakly references instances with properties bound
-local weak: { Instance? } = setmetatable({}, { __mode = "v" }) :: any
-
--- unique binding id
-local bind_count = 0
 
 -- todo: replace with throw's method
 local root do
@@ -74,45 +67,21 @@ function bind(instance: Instance, property: string, setter: (Instance) -> ())
         end
     end
 
-    local node = create(false)
+    local binding = create(instance)
 
-    create_and_open_scope(node)
+    init_scope(binding)
 
     -- run setter to capture any nodes being depended on
     local nodes = (capture(setter :: () -> unknown, instance))
 
     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
+    binding.effect = setter
 
     -- register the setter as a side-effect of each node
-    for _, n in next, nodes do
-        set_child(n, node)
+    for _, node in next, nodes do
+        add_child(node, binding)
     end
-
-    
-    
-    -- store reference of instance proxy without preventing gc
-    weak[bind_id] = instance
-
-    local function ref()
-        local _ = node -- prevent gc of node being depended on
-        local instance = weak[bind_id] :: Instance
-
-        -- keep proxy in memory if instance is still parented
-        hold[bind_id] = instance.Parent and instance or nil
-    end
-
-    ref()
-    instance:GetPropertyChangedSignal("Parent"):Connect(ref)
 end
 
 local function bind_property(instance: Instance, property: string, fn: () -> unknown)

src/cleanup.luau

@@ -13,130 +13,3 @@ local function cleanup(fn: () -> ())
 end
 
 return cleanup
-
---[[
-
-Cleanups associate a callback with an arbitrary value with an unknown lifetime.
-Anytime a new callback is registered with a value that already has one registered,
-the registered callback is ran and then replaced with the new one.
-
-When the value is eventually garbage collected, Vide checks for callbacks
-without an associated value, which it will then run and clear, recycling its
-cleanup id.
-
-By default the arbitrary value is the function object that calls `cleanup()`.
-There are exceptions such as with `indexes()` and `values()` where the
-arbitrary value is manually set to be the new source created instead of the
-caller, as the same caller can be used to create multiple new objects.
-
-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
-local id_to_ref = {} :: { [number]: string }
--- 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" })
-
--- detects in strict mode when multiple cleanups are registered in the same scope
-local debug_caller_to_line = {} :: { [() -> ()]: number }
-setmetatable(debug_caller_to_line, { __mode = "k" })
-
--- when active, cleanup callbacks are not automatically registered but are
--- added to an array for manual registering internally
-local manual_mode = {
-    caller = false :: false | () -> (),
-    callbacks = {} :: { () -> () }
-}
-
--- todo: rare case where mem address is reused by another function
--- does this case handle itself?
-
--- registers a callback with the given lifetime using the given ref
-local function cleanup_ref(ref: string, lifetime: unknown, callback: () -> ())
-    local id = ref_to_id[ref]
-
-    if id then -- invoke previously registered callback then register new one
-        cleanup_callbacks[id]()
-        cleanup_lifetime[id] = lifetime -- rare case where ref is reused while lifetime is nil
-    else -- no previously registered callback, add and register new one
-        id = #cleanup_callbacks + 1
-        ref_to_id[ref] = id
-        id_to_ref[id :: any] = ref -- todo
-        cleanup_lifetime[id :: any] = lifetime -- todo
-    end
-
-    cleanup_callbacks[id] = callback
-end
-
--- registers a callback with its caller as the lifetime, and caller address as the ref
-local function cleanup(callback: () -> ())
-    local lifetime = debug.info(2, "f") -- `caller of cleanup() is lifetime of cleanup`
-
-    if flags.strict then
-        local line = debug.info(2, "l")
-        local cur_line = debug_caller_to_line[lifetime]
-        if cur_line and cur_line ~= line then
-            throw "only one cleanup call is allowed per function scope"
-        end
-        debug_caller_to_line[lifetime] = line
-    end
-
-    if manual_mode.caller == lifetime then
-        table.insert(manual_mode.callbacks, callback)
-    else
-        local ref = tostring(lifetime)
-        cleanup_ref(ref, lifetime, callback)
-    end
-end
-
-local function clean_garbage()
-    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
-
-                local ref = id_to_ref[id]
-                local max_ref = id_to_ref[max_id]
-
-                id_to_ref[id] = max_ref
-                id_to_ref[max_id] = nil
-
-                ref_to_id[max_ref] = id
-                ref_to_id[ref] = nil
-            end
-
-            local ok, err: string? = pcall(callback)
-            if not ok then warn(`error occured during cleanup: {err}`) end
-        end
-    end
-end
-
-local manual_cleanup_mode = function(caller: () -> ()?)
-    if caller == nil then
-        local clone = table.clone(manual_mode.callbacks)
-        manual_mode.caller = false
-        table.clear(manual_mode.callbacks)
-        return clone
-    else
-        manual_mode.caller = caller
-    end
-    return manual_mode.callbacks
-end :: ( (caller: (...any) -> ()) -> () ) & ( (nil) -> { () -> () } )
-
-return function() return cleanup, clean_garbage, manual_cleanup_mode, cleanup_ref end
-]]

src/derive.luau

@@ -2,20 +2,38 @@ 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 capture = graph.capture
+local add_child = graph.add_child
+local set_effect = graph.set_effect
+local update = graph.update
+local track = graph.track
+local init_scope = graph.init_scope
 local close_scope = graph.close_scope
 
 local function derive<T>(fn: () -> T): () -> T
-    local node, read_node_value = create((false :: any) :: T)
+    local node = create((false :: any) :: T)
 
-    create_and_open_scope(node)
+    init_scope(node)
 
-    node.cache = capture_and_link(node, fn)
+    local nodes, value = capture(fn)
 
     close_scope()
 
-    return read_node_value
+    for _, parent in next, nodes do
+        add_child(parent, node)
+    end
+
+    set_effect(node, function()
+        node.cache = fn()
+        update(node)
+    end)
+
+    node.cache = value
+
+    return function()
+        track(node)
+        return node.cache
+    end
 end
 
 return derive

src/graph.luau

@@ -6,7 +6,8 @@ local on_gc = require(script.Parent.on_gc)()
 
 export type Node<T> = {
     cache: T,
-    effect:  () -> (),
+    effect:  (unknown) -> (),
+    parents: { Node<T> } | false,
     children: { Node<T> } | false, -- weak values
     cleanups: { () -> () } | false
 }
@@ -98,68 +99,80 @@ local function set_effect<T>(node: Node<unknown>, fn: () -> ())
 end
 
 local function run_effect(node: Node<unknown>)
-    node.effect()
-end
-
--- retrieves a node's cached value
--- add self to refs if ref capture flag is enabled
-local function get<T>(node: Node<T>): T
-    if reff then table.insert(refs, node) end
-    return node.cache
+    node.effect(node.cache)
 end
 
 -- links two nodes as parent-child
-local function set_child(parent: Node<unknown>, child: Node<unknown>)
+local function add_child(parent: Node<unknown>, child: Node<unknown>)
     if parent.children then
         table.insert(parent.children, child)    
     else
         parent.children = { child }
-        setmetatable(parent.children :: any, WEAK_VALUES)
+        setmetatable(parent.children :: any, {})
     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
+local function add_children(parent: Node<unknown>, children: { Node<unknown> })
+    if parent.children then
+        for _, child in next, children do
+            table.insert(parent.children, child)
         end
     else
-        node.cleanups = {}
-        local cleanups = node.cleanups :: { () -> () }
-        on_gc(node, function()
-            run_cleanups({ cleanups = cleanups })
-        end)
+        parent.children = table.clone(children)
+    end
+end
+
+local function add_parent(child: Node<unknown>, parent: Node<unknown>)
+    child.parents = { parent }
+end
+
+local function rec(node: { effect: any, children: { Node<unknown> }, cleanups: { () -> () }})
+    run_cleanups(node)
+    node.effect = function() assert(false) end
+    if node.children then
+        for _, child in node.children do
+            rec(child)
+        end
+    end
+end
+
+local function destroy(node: Node<unknown>)
+    if node.parents then
+        for _, parent in node.parents do
+            parent.children[table.find(parent.children, node)] = nil -- todo: can iter invalidation occur here?
+        end
+    end
+    rec(node)
+end
+
+local function init_scope(node: Node<unknown>)
+    local parent = scopes[scopes.n]
+    if parent then
+        add_child(parent, node)
+        add_parent(node, parent)
     end
     open_scope(node)
 end
 
 -- runs node effects, recalculates descendants and runs descendant effects
 local function update(node: Node<unknown>)
-    open_scope(node)
-    run_cleanups(node)
-    run_effect(node)
-    close_scope()
     if node.children then
         for _, child in node.children do
+            open_scope(child)
+            run_cleanups(child)
+            run_effect(child)
             update(child)
+            close_scope()
         end
     end
 end
 
--- sets a node's cached value and updates all descendants
-local function set<T>(node: Node<T>, value: T)
-    node.cache = value
-    update(node)
-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.effect = function()
         child.cache = derive()
     end
-    set_child(parent, child)
+    add_child(parent, child)
 end
 
 -- detect what nodes were referenced in the given callback and returns them in an array
@@ -192,39 +205,43 @@ local function capture_and_link<T>(child: Node<T>, derive: () -> T): T
         child.cache = derive()
     end
     for _, parent: Node<unknown> in next, nodes do
-        set_child(parent, child)
+        add_child(parent, child)
     end
 
     return value :: T
 end
 
-local function create<T>(value: T): (Node<T>, () -> T)
+local function track(node: Node<unknown>)
+    if reff then table.insert(refs, node) end
+end
+
+local function create<T>(value: T): Node<T>
     local node = {
         cache = value,
         effect = function() end,
+        parents = false :: false,
         children = false :: false,
         cleanups = false :: false
     }
 
-    local function read_node_value()
-        return get(node)
-    end
-
-    return node, read_node_value
+    return node
 end
 
 return table.freeze {
-    create_and_open_scope = create_and_open_scope,
+    init_scope = init_scope,
     open_scope = open_scope,
     close_scope = close_scope,
     get_scope = get_scope,
     add_cleanup = add_cleanup,
+    destroy = destroy,
     run_cleanups = run_cleanups,
     set_effect = set_effect,
-    get = get,
-    set = set,
+    track = track,
+    update = update,
     link = link,
-    set_child = set_child,
+    add_parent = add_parent,
+    add_child = add_child,
+    add_children = add_children,
     capture = capture,
     capture_and_link = capture_and_link,
     create = create :: (<T>(value: T) -> (Node<T>, () -> T)) & (<T>() -> (Node<T>, () -> T)),

src/maps.luau

@@ -11,11 +11,12 @@ 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 open_new_scope = graph.open_new_scope
 local get_scope = graph.get_scope
 local open_scope = graph.open_scope
 local close_scope = graph.close_scope
 local link = graph.link
+local destroy_tree = graph.destroy_tree
 
 type Map<K, V> = { [K]: V }
 
@@ -48,7 +49,7 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
 
         -- remove queued values
         for _, i in next, remove_queue do
-            run_cleanups(scopes[i])
+            destroy_tree(scopes[i])
 
 
             input_cache[i] = nil
@@ -67,7 +68,7 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
                 if cv == nil then
                     local scope = create(false)
 
-                    create_and_open_scope(scope)
+                    open_new_scope(scope)
 
                     local node, get_value = create(v)
                     input_nodes[i] = node
@@ -94,7 +95,10 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
 
     local output, read_output_value = create(nil :: any)
 
+    local scope = create(false)
+    
     local function derive()
+        local _ = scope
         return recompute(input())
     end
 
@@ -106,13 +110,11 @@ local function indexes<K, VI, VO>(input: () -> Map<K, VI>, transform: (() -> VI,
 
     output.cache = recompute(value)
 
-    cleanup_ref(tostring(output), output, function()
-        for _, callbacks in next, cleanups do
-            for _, callback in next, callbacks do
-                callback() -- todo: pcall
-            end
-        end
-    end)
+
+
+    local scope_parent = get_scope()
+
+    set_child(scope_parent, scope)
 
     return read_output_value
 end

src/root.luau

@@ -2,22 +2,35 @@ if not game then script = require "test/relative-string" end
 
 local flags = require(script.Parent.flags)
 local throw = require(script.Parent.throw)
+local on_gc = require(script.Parent.on_gc)()
 local graph = require(script.Parent.graph)
+type Node<T> = graph.Node<T>
 local create = graph.create
-local create_and_open_scope = graph.create_and_open_scope
+local init_scope = graph.init_scope
 local close_scope = graph.close_scope
 local get_scope = graph.get_scope
-local add_cleanup = graph.add_cleanup
+local destroy = graph.destroy
+
+local refs = {} :: { [Node<unknown>]: unknown }
+setmetatable(refs :: any, { __mode = "v" })
 
 local function root<T>(fn: () -> T): T
+    assert(not get_scope())
+
     local node = create(nil) -- todo: lifetime with return vaue from fn
 
-    create_and_open_scope(node)
+    init_scope(node)
 
     local v = fn()
 
     close_scope()
 
+    refs[node] = v
+
+    on_gc(v, function()
+        destroy(node)
+    end)
+
     return v
 end
 

src/source.luau

@@ -3,22 +3,29 @@ if not game then script = require "test/relative-string" end
 local graph = require(script.Parent.graph)
 type Node<T> = graph.Node<T>
 local create = graph.create
-local set = graph.set
+local track = graph.track
+local update = graph.update
 
 export type Source<T> = (() -> T) & ((T) -> T)
 
-local function source<T>(value: T): Source<T>
-    local node, read_node_value = create(value :: T)
+local function source<T>(initial_value: T): Source<T>
+    local node = create(initial_value)
 
     return function(...): T
-        if select("#", ...) == 0 then return read_node_value() end -- check if any args were given
+        if select("#", ...) == 0 then -- no args were given
+            track(node)
+            return node.cache
+        end
 
         local v = ... :: T
-        if node.cache == v and (type(v) ~= "table" or table.isfrozen(v)) then return v end
+        if node.cache == v and (type(v) ~= "table" or table.isfrozen(v)) then 
+            return v
+        end
 
-        set(node, v)
+        node.cache = v
+        update(node)
         return v
     end
 end
 
-return source :: (<T>(value: T) -> Source<T>) & (<T>() -> Source<T>)
+return source :: (<T>(initial_value: T) -> Source<T>) & (<T>() -> Source<T>)

src/watch.luau

@@ -2,17 +2,17 @@ if not game then script = require "test/relative-string" end
 
 local graph = require(script.Parent.graph)
 local create = graph.create
-local set_child = graph.set_child
+local add_parent = graph.add_parent
+local add_child = graph.add_child
 local capture = graph.capture
-local create_and_open_scope = graph.create_and_open_scope
+local init_scope = graph.init_scope
 local close_scope = graph.close_scope
-
-local ref = {}
+local destroy = graph.destroy
 
 local function watch(effect: () -> ()): () -> ()
-    local node = create(nil)
+    local node = create(false)
 
-    create_and_open_scope(node)
+    init_scope(node)
 
     local nodes = capture(effect :: () -> nil)
 
@@ -20,17 +20,14 @@ local function watch(effect: () -> ()): () -> ()
 
     node.effect = effect
 
-    -- register effect with permanent lifetime
     for _, parent in next, nodes do
-        set_child(parent, node)  
+        add_parent(node, parent)
+        add_child(parent, node)
     end
 
-    ref[node] = true -- prevent gc of node
 
     local function unwatch()
-        -- unregister effect from all nodes
-        node.effect = function() end
-        ref[node] = nil
+        destroy(node)
     end
 
     return unwatch

test/tests.luau

@@ -21,132 +21,50 @@ end
 TEST("graph", function()
     local graph = require "src/graph"
     local create = graph.create
-    local get = graph.get
-    local set = graph.set
+    local track = graph.track
     local capture = graph.capture
-    local capture_and_link = graph.capture_and_link
-    local link = graph.link
-    local set_effect = graph.set_effect
+    local update = graph.update
+    local add_child = graph.add_child
 
     do CASE "node creation"
         local node = create(1)
-        CHECK(get(node) == 1)
-    end
-
-    do CASE "node value"
-        local node = create(0)
-        set(node, 1)
-        CHECK(get(node) == 1)
-        set(node, 2)
-        CHECK(get(node) == 2)
+        CHECK(node.cache == 1)
     end
 
     do CASE "capture nodes"
         local node1 = create(nil)
         local node2 = create(nil)
-        local nodes = capture(function()
-            return get(node1), get(node2)
+        local captured = capture(function()
+            track(node1)
+            track(node2)
+            return nil
         end)
-        CHECK(nodes[1] == node1)
-        CHECK(nodes[2] == node2)
+        CHECK(captured[1] == node1)
+        CHECK(captured[2] == node2)
     end
 
     do CASE "linking nodes"
         local parent = create(1)
         local child = create(0)
 
-        link(parent, child, function() 
-            return get(parent)
-        end)
+        add_child(parent, child)
 
-        set(parent, get(parent) + 1)
-        CHECK(get(child) == 2) -- child should automatically update
+        local ran = false
+        child.effect = function()
+            ran = true
+        end
+
+        update(parent)
+        CHECK(ran)
     end
 
-    do CASE "capture and link nodes"
-        local parent = create(1)
-        local child = create()
-
-        child.cache = capture_and_link(child, function()
-            return tostring(get(parent))
-        end)
-
-        set(parent, 2)
-        CHECK(get(child) == "2")
-    end
+    -- todo: further tests
 
     do CASE "nodes garbage collection"
         local wref = weak { create(1) }
         gc()
         CHECK(not wref[1])
     end
-
-    do CASE "node effect garbage collection"
-        do
-            local wref
-
-            do
-                local function factory(p) -- factory function to prevent closure caching
-                    return function()
-                        return get(p)
-                    end
-                end
-
-                local node = create(1)
-                
-                do
-                    local effect1 = factory(node)
-                    local effect2 = factory(node)
-
-                    wref = weak { e1 = effect1, e2 = effect2, n = node}
-
-                    set_effect(node, effect1, {})
-                    set_effect(node, effect2, true)
-                end
-
-                gc()
-                CHECK(not wref.e1) -- effect1 should gc since nothing is referencing table `t`
-                CHECK(wref.e2) -- effect2 should not gc as `true` is not garbage collectable
-            end
-
-            gc()
-            CHECK(not wref.n and not wref.e2) -- node should now gc along with effect2
-        end
-
-        do
-            local wref
-
-            do -- same test but for multiple nodes referenced by watcher
-                local function factory(a, b)
-                    return (function(c, d)
-                        return function()
-                            return get(c), get(d)
-                        end
-                    end)(a, b)
-                end
-
-                local node1 = create(1)
-                local node2 = create(1)
-
-                do 
-                    local effect = factory(node1, node2)
-
-                    wref = weak { n1 = node1, n2 = node2, e = effect }
-
-                    local t1 = {}
-                    set_effect(node1, effect, t1)
-                    set_effect(node2, effect, t1)
-                end
-
-                gc()
-                CHECK(not wref.e)
-            end
-
-            gc()
-            CHECK(not wref.n1)
-            CHECK(not wref.n2)
-        end
-    end
 end)
 
 TEST("source()", function()
@@ -154,78 +72,65 @@ TEST("source()", function()
     local watch = vide.watch
 
     do CASE "create source"
-        local state = source(1)
-        CHECK(state() == 1)
+        local src = source(1)
+        CHECK(src() == 1)
     end
 
     do CASE "set and get source value"
-        local state = source(1)
-        state(2)
-        CHECK(state() == 2)
+        local src = source(1)
+        src(2)
+        CHECK(src() == 2)
     end
 
     do CASE "does not update if same value"
-        local state = source(1)
+        local src = source(1)
 
-        local updates = -1
+        local count = -1
         watch(function()
-            state()
-            updates += 1
+            src()
+            count += 1
         end)
 
-        CHECK(updates == 0)
-        state(1)
-        CHECK(updates == 0)
-        state(2)
-        CHECK(updates == 1)
+        CHECK(count == 0)
+        src(1)
+        CHECK(count == 0)
+        src(2)
+        CHECK(count == 1)
     end
 
-    do CASE "does update if same value is table"
-        local state = source {}
+    do CASE "does update if same value is mutable table"
+        local src = source {}
 
-        local updates = -1
+        local count = -1
         watch(function()
-            state()
-            updates += 1
+            src()
+            count += 1
         end)
 
-        CHECK(updates == 0)
-        state(state())
-        CHECK(updates == 1)
+        CHECK(count == 0)
+        src(src())
+        CHECK(count == 1)
     end
 
     do CASE "does not update if same value is frozen table"
         local a = table.freeze {}
         local b = table.freeze {}
 
-        local state = source(a)
+        local src = source(a)
 
-        local updates = -1
+        local count = -1
         watch(function()
-            state()
-            updates += 1
+            src()
+            count += 1
         end)
 
-        CHECK(updates == 0)
-        state(a)
-        CHECK(updates == 0)
-        state(b)
-        CHECK(updates == 1)
-        state(b)
-        CHECK(updates == 1)
-    end
-
-    do CASE "garbage collection of node"
-        local capture = require "src/graph".capture
-        local src = source(0)
-
-        local wref do
-            local node = unpack(capture(src))
-            wref = weak { node }
-        end
-
-        gc()
-        CHECK(not wref[1])
+        CHECK(count == 0)
+        src(a)
+        CHECK(count == 0)
+        src(b)
+        CHECK(count == 1)
+        src(b)
+        CHECK(count == 1)
     end
 end)
 
@@ -234,130 +139,48 @@ TEST("derive()", function()
     local derive = vide.derive
 
     do CASE "derive new value on source change"
-        local inputA = source(1)
-        local inputB = source(2)
+        local a = source(1)
+        local b = source(2)
 
-        local output = derive(function()
-            return tostring(inputA() + inputB())
+        local c = derive(function()
+            return tostring(a() + b())
         end)
 
-        CHECK(output() == "3")
-        inputA(2)
-        CHECK(output() == "4")
+        CHECK(c() == "3")
+        a(2)
+        CHECK(c() == "4")
     end
 
     do CASE "derive wrapped source"
-        local input = source(1)
+        local a = source(1)
 
-        local transform = function()
-            return tostring(input())
+        local b = function()
+            return tostring(a())
         end
 
-        local output = derive(function()
-            return tonumber(transform())
+        local c = derive(function()
+            return tonumber(b())
         end)
 
-        CHECK(output() == 1)
-        input(2)
-        CHECK(output() == 2)
+        CHECK(c() == 1)
+        a(2)
+        CHECK(c() == 2)
     end
 
     do CASE "garbage collection"
-        do -- check that `b` does not allow gc of `a`
-            local wref, b
+        -- check that `b` does not allow gc of `a`        
+        local a = source(1)
 
-            do
-                local a = source(1)
+        local b = derive(function()
+            return a()
+        end)
 
-                b = derive(function()
-                    return a()
-                end)
+        b = nil :: any
 
-                wref = weak { a }
-            end
-
-            gc()
-            CHECK(wref[1])
-            b()
-        end
-
-        do -- check that `a` allows gc of `b`
-            local a = source(1)
-
-            local wref
-
-            do
-                local b = derive(function()
-                    return a()
-                end)
-
-                wref = weak { b }
-            end
-
-            gc()
-            CHECK(not wref[1])
-        end
-    end
-
-    do CASE "garbage collection 2"
-        -- creats a chain `a -> b -> c` where `a` is the source
-        local function setup()
-            local a = source(0)
-
-            local b = derive(function()
-                return a()
-            end)
-
-            local c = derive(function()
-               return b()
-            end)
-
-            return weak { a, b, c }, a, b, c
-        end
-
-        do -- check that `b` and `c` can gc if `a` is referenced
-            local wref, _a = setup()
-
-            gc()
-            CHECK(not wref[2])
-            CHECK(not wref[3])
-        end
-
-        do -- check that `a` and `b` wont gc if `c` is referenced
-            local weak, _a, _b, _c = setup()
-
-            _a, _b = nil :: any, nil :: any
-
-            gc()
-            CHECK(weak[1])
-            CHECK(weak[2])
-        end
-
-        do -- check that `b` wont gc if `a` and `c` are referenced
-            local weak, a, _b, c = setup()
-
-            _b = nil :: any
-
-            gc()
-            CHECK(weak[2])
-
-            a(2)
-            CHECK(c() == 2)
-        end
-    end
-
-    do CASE "garbage collection of node"
-        local capture = require "src/graph".capture
-        local input = source(1)
-
-        local wref do
-            local output = derive(input)
-            local output_node = unpack(capture(output))
-            wref = weak { output_node }
-        end
+        local wref = weak { a }
 
         gc()
-        CHECK(not wref[1])
+        CHECK(wref[1])
     end
 end)
 
@@ -366,63 +189,63 @@ TEST("watch()", function()
     local watch = vide.watch
     local cleanup = vide.cleanup
 
-    do CASE "capture sourcess"
+    do CASE "capture sources"
         local a = source(1)
         local b = source(1)
 
-        local runcount = -1
+        local count = 0
         watch(function()
             a()
             b()
-            runcount += 1
+            count += 1
         end)
 
-        CHECK(runcount == 0)
+        CHECK(count == 1)
         a(2)
-        CHECK(runcount == 1)
+        CHECK(count == 2)
         b(2)
-        CHECK(runcount == 2)
+        CHECK(count == 3)
     end
 
     do CASE "stop watch"
         local a = source(1)
 
-        local runcount = -1
+        local count = 0
         local unwatch = watch(function()
             a()
-            runcount += 1
+            count += 1
         end)
         
         unwatch()
         a(2)
-        CHECK(runcount == 0)
+        CHECK(count == 1)
     end
 
     do CASE "side-effect cleanup"
         local state = source(1)
 
-        local effect_runcount = 0
-        local cleanup_runcount = 0
+        local effect_count = 0
+        local cleanup_count = 0
 
         local unwatch = watch(function()
             state()
-            effect_runcount += 1
-            cleanup(function() cleanup_runcount += 1 end)
+            effect_count += 1
+            cleanup(function() cleanup_count += 1 end)
         end)
 
-        CHECK(effect_runcount == 1)
-        CHECK(cleanup_runcount == 0)
+        CHECK(effect_count == 1)
+        CHECK(cleanup_count == 0)
         state(2)
-        CHECK(effect_runcount == 2)
-        CHECK(cleanup_runcount == 1)
+        CHECK(effect_count == 2)
+        CHECK(cleanup_count == 1)
 
         unwatch()
         unwatch = nil :: any
         gc()
         vide.step(0)
 
-        CHECK(effect_runcount == 2)
-        CHECK(cleanup_runcount == 2)
+        CHECK(effect_count == 2)
+        CHECK(cleanup_count == 2)
     end
 
     do CASE "garbage collection"
@@ -574,26 +397,6 @@ TEST("cleanup()", function()
         CHECK(objB.cleaned == 2)
     end
 
-    -- this is not allowed, test to verify behavior anyways
-    do CASE "multiple cleanup"
-        local state = source(1)
-
-        local queue = {}
-    
-        watch(function()
-            state()
-            cleanup(function() table.insert(queue, 1) end)
-            cleanup(function() table.insert(queue, 2) end)
-        end)
-
-        CHECK(testkit.seq(queue, { 1 }))
-        state(2)
-        CHECK(testkit.seq(queue, { 1, 2, 1 }))
-        state(3)
-        CHECK(testkit.seq(queue, { 1, 2, 1, 2, 1 }))
-    end
-
-    --[[
     do CASE "multiple cleanup"
         local state = source(1)
 
@@ -610,18 +413,15 @@ TEST("cleanup()", function()
         CHECK(testkit.seq(queue, { 1, 2 }))
         state(3)
         CHECK(testkit.seq(queue, { 1, 2, 1, 2 }))
-
-        do
-            state = nil :: any
-            gc()
-            vide.step(0)
-        end
-
-        -- todo: guarantee call order when gc? (currently not)
-        --testkit.print2(queue)
-        --CHECK(testkit.seq(queue, { 1, 2, 1, 2, 1, 2 }))
     end
-    ]]
+
+    do CASE "no scope"
+        local ok = pcall(function()
+            cleanup(function() end)
+        end)
+
+        CHECK(not ok)
+    end
 end)
 
 TEST("create()", function()
@@ -822,9 +622,11 @@ TEST("create()", function()
                     Text = state,
                 }
 
+                local binding = assert(node.children)[1]
+
                 wref = weak {
                     instance = instance,
-                    binding = next(node.effects)
+                    binding = binding
                 }
             end
             

todo.md

@@ -15,6 +15,7 @@
     - look into SolidJS's reactive contexts
 - solution to nested reactivity, see: SolidJS stores
 - SolidJS control flow components
+- equality checking of derived sources
   - Show
   - Switch
   - Dynamic