Initial commit

src/wrap.lua

@@ -0,0 +1,42 @@
+------------------------------------------------------------------------------------------
+-- vide/wrap.lua
+------------------------------------------------------------------------------------------
+
+if not game then script = (require :: any) "test/wrap-require" end
+
+local graph = require(script.Parent.graph)
+type State<T> = graph.State<T>
+type MaybeState<T> = graph.MaybeState<T>
+local create = graph.create
+local get = graph.get
+local set = graph.set
+local wrapped = graph.wrapped
+
+local throw = require(script.Parent.throw)
+local flags = require(script.Parent.flags)
+
+type Setter<T> = (value: MaybeState<T> | (MaybeState<T>) -> MaybeState<T>, force: boolean?) -> T
+
+local function wrap<T>(value: MaybeState<T>?): (State<T>, Setter<T>)
+    local state = create(if wrapped(value) then get(value :: State<T>) else value :: T)
+
+    local function setter(vi: MaybeState<T> | (MaybeState<T>) -> MaybeState<T>, force: boolean?): T
+        if type(vi) == "function" then
+            vi = vi(get(state))
+        end
+
+        local v = if wrapped(vi) then get(vi :: State<T>) else vi :: T
+
+        if v ~= state.cache or force then
+            set(state, v)
+        elseif flags.strict and type(v) == "table" then
+            throw("attempt to set same table object")   
+        end
+
+        return v
+    end
+
+    return state, setter 
+end
+
+return wrap