Merge branch 'centau:main' into main

src/apply.luau

@@ -23,6 +23,9 @@ type Cache = {
         Array<(Instance) -> ()> -- action callbacks
     >,
 
+    -- what to parent the instance to after running actions
+    parent: unknown,
+
     -- cache to detect duplicate property setting at same nesting depth
     nested_debug: Map<
         number, -- depth
@@ -47,6 +50,7 @@ local function borrow_cache(): Cache
             actions = setmetatable({} :: any, { -- lazy init
                 __index = function(self, i) self[i] = {}; return self[i] end
             }),
+            parent = nil,
             nested_debug = setmetatable({} :: any, {
                 __index = function(self, i: number) self[i] = {}; return self[i] end
             }),
@@ -61,8 +65,6 @@ end
 
 local function process_properties(properties: Map<unknown, unknown>, instance: Instance, cache: Cache, depth: number)
     for property, value in properties do
-        if property == "Parent" then continue end
-
         if type(property) == "string" then
             if flags.strict then -- check for duplicate property assignment at nesting depth
                 if cache.nested_debug[depth][property] then
@@ -71,6 +73,11 @@ local function process_properties(properties: Map<unknown, unknown>, instance: I
                 cache.nested_debug[depth][property] = true
             end
 
+            if property == "Parent" then
+                cache.parent = value
+                continue
+            end
+
             if type(value) == "function" then 
                 if typeof((instance :: any)[property]) == "RBXScriptSignal" then
                     table.insert(cache.events, property) -- add event name to buffer
@@ -93,7 +100,7 @@ local function process_properties(properties: Map<unknown, unknown>, instance: I
                 else
                     process_properties(value :: Map<unknown, unknown>, instance, cache, depth + 1)
                 end
-            else
+            elseif type(value) == "userdata" then
                 (value :: Instance).Parent = instance -- parent child
             end
         end
@@ -106,9 +113,6 @@ local function apply<T>(instance: T & Instance, properties: { [unknown]: unknown
         error "attempt to call a constructor returned by create() with no properties"
     end
 
-    -- queue parent assignment if any for last
-    local parent: unknown = properties.Parent 
-
     local caches = borrow_cache()
     local events = caches.events
     local actions = caches.actions
@@ -135,6 +139,7 @@ local function apply<T>(instance: T & Instance, properties: { [unknown]: unknown
         end
     end
 
+    local parent = caches.parent
     if parent then
         if type(parent) == "function" then
             implicit_effect.parent(instance, parent :: () -> Instance)
@@ -145,6 +150,7 @@ local function apply<T>(instance: T & Instance, properties: { [unknown]: unknown
 
     table.clear(events)
     for _, queued in next, actions do table.clear(queued) end
+    caches.parent = nil
     if flags.strict then table.clear(nested_debug) end
     table.clear(nested_stack)
 

src/show.luau

@@ -1,16 +1,33 @@
-local switch = require "./switch"
+local source = require "./source"
+local derive = require "./derive"
+local effect = require "./effect"
+local untrack = require "./untrack"
 
-local function show<T>(source: () -> any, component: () -> T, fallback: (() -> T)?): () -> T?
-    local function truthy()
-        return not not source()
-    end
+local function show<T, U>(input: () -> T?, component: (() -> T) -> U, fallback: (() -> U)?): () -> U?
+    local filtered_input = source()
 
-    return switch(truthy) {
-        [true] = component,
-        [false] = fallback,
-    }
+    effect(function()
+        local v = input() 
+        if v then
+            filtered_input(v)
+        end
+    end)
+
+    local input_is_truthy = derive(function()
+        return not not input()
+    end)
+
+    -- todo: is this needed?
+    -- local filtered_input_is_truthy = derive(function()
+    --     return not not filtered_input()
+    -- end)
+
+    return derive(function()
+        return
+            if input_is_truthy() then untrack(function() return component(filtered_input :: () -> T) end)
+            elseif fallback then untrack(fallback)
+            else nil
+    end)
 end
 
-return show ::
-    (<T>(source: () -> any, component: () -> T) -> () -> T?) &
-    (<T, U>(source: () -> any, component: () -> T, fallback: () -> U) -> () -> (T | U)?)
+return show

src/untrack.luau

@@ -22,4 +22,4 @@ local function untrack<T>(source: () -> T): T
     end
 end
 
-return untrack
+return untrack :: ( <T>(fn: () -> T) -> T ) & ( (fn: () -> ()) -> () )