Polyfilling algebraic data types for js

adt.js

//first attempt
//requirements:
//- must be polyfillable
//  aka can be used as a library (though always recommended to be compiled)
//- syntax must be friendly
var board_viewer = data ({
	board_viewer: (board = board, questions = list (question), history = history) => board_viewer })
var list = a =>
	data
	({ nil: () => list (a)
	, cons: (head = a, tail = list (a)) => list (a) })

//various experiments
var board_viewer = data ({
	board_viewer: (board = ~ board, questions = ~ list (question), history = ~ history) => board_viewer })

var board_viewer = data ({
	board_viewer: ({_} =- board) => (questions =- list (question)) => ({_} =- history) => ({_} =- board_viewer) })

var board_viewer = data ({
	board_viewer: (board =- board) => (questions =- list (question)) => (history =- history) => board_viewer })

var board_viewer = data ({
	board_viewer: ({_} =- board) => (questions =- list (question)) => ({_} =- history) => ({_} =- board_viewer) })

var board_viewer = data ({
	board_viewer: { board :- board, questions :- list (question), history :- history }	[board_viewer] })

var board_viewer = data ({
	board_viewer: { board :- board, questions :- list (question), history :- history } |- board_viewer })

var board_viewer = data ({
	board_viewer: { board :- board, questions :- list (question), history :- history } ** { board_viewer } })

var board_viewer = data ({
	board_viewer: board -+ list (question) [typeof questions] -+ history [typeof history] -+ board_viewer })

var board_viewer = data ({
	board_viewer: board .board -+ list (question) .questions -+ history .history -+ board_viewer })

var board_viewer = data ({
	board_viewer: board, board => list (question), questions => history, history => board_viewer })

var board_viewer = data ([
	board, board => list (question), questions => history, history => board_viewer, board_viewer ])

var board_viewer = data ({
	board_viewer: board|( board => list (question)|( questions => history|( history => board_viewer ))) })

//current draft
//- polyfillable; this one relies on `valueOf` coercion from types, so valueOf is hijacked for all registered types
//- polyfillable; order of records can be determined; defacto, records preserve order, plus, function can be inspected toString
//- syntax borrows from both adts and gadts
//- allows grouping of similar gadt return types
//- allows collisions of record-name and type variable name (while still being polyfillable)
//- allows omitting of type and omitting of tag name (while still being polyfillable)
//- allows omitting of singular constructor
//- automatically disallows repeated constructor names

var board_viewer = data 
	(( board_viewer = { board :- board, questions :- list (question), history :- history } ) => board_viewer )
var board_viewer = data 
	(( _ = { _ :- board, questions :- list (question), _ :- history } ) => board_viewer )
var board_viewer = data
	(( _ = { board, questions, history } ) => board_viewer )
var list = a =>
	data
	(( nil
	, cons = { head :- a, tail :- list (a) } ) => list (a) )
var list = a =>
	data
	(( nil
	, cons = { _ :- a, _ :- list (a) } ) => list (a) )
var expr = a =>
	data
	(( bool = { _ :- bool } ) => expr (bool),
	( int = { _ :- int } ) => expr (int) )