RFC: Export Type Barrel

[StoryBakeryDev]

Rendered

This RFC proposes a type-only barrel form for forwarding exported types from one module through another:

-- Child.luau
export type A<T, U> = ...
export type B = ...
export type C = ...

-- Interface.luau
export type * from "@self/Child"

-- Consumer.luau
local Interace = require("./Interface")

local a: Interace.A<any, any>
local b: Interace.B
local c: Interace.C

[Crazyblox]

This might not be what you are looking for, but I wanted to explore syntax for this on the side of the requirer rather than the export.

-- All export types: Assign to requirer top level.
type require("path/to/module")

-- All export types: Assign to requirer top level with option to reassign type names, preventing clashing.
type SpecificType = string
type require("path/to/module") {RenamedSpecificType = SpecificType}

-- Single export type: Assign to requirer top level.
type require("path/to/module").SpecificType

-- Single export type: Assign to requirer top level with option to reassign, preventing clashing.
type SpecificType = string
type RenamedSpecificType = require("path/to/module").SpecificType

[TenebrisNoctua]

Couldn't this be achieved in a more simplistic manner as:

local module = require("path/to/module")
export type module -- All types from the module can now be exported in this simplistic syntax.

You could still do:

local module = require("path/to/module")
export type A = module.A

For better control. This would use the existing type resolving system with require(), and may be less expensive to implement.