#lang typed/racket/base
(require sugar/list)
(require (for-syntax racket/syntax racket/base) racket/string racket/list sugar/debug racket/bool hyphenate racket/function math/flonum)
(require "quads-typed.rkt" "world-typed.rkt" "measure-typed.rkt")


;; predicate for use below
(: list-of-mergeable-attrs? (Any . -> . Boolean))
(define (list-of-mergeable-attrs? xs)
  (and (list? xs) (andmap (λ(x) (or (quad? x) (quad-attrs? x) (hashable-list? x))) xs)))

;; faster than (listof pair?)
(: pairs? (Any . -> . Boolean))
(define (pairs? x) (and (list? x) (andmap pair? x)))


;; push together multiple attr sources into one list of pairs.
;; mostly a helper function for the two attr functions below.
(: join-attrs ((Listof (U Quad QuadAttrs)) . -> . QuadAttrs))
(define (join-attrs quads-or-attrs-or-lists)
;  (list-of-mergeable-attrs? . -> . pairs?)
  (append-map hash->list (filter-not false? (map (λ(x)
                                                   (cond
                                                     [(quad? x) (quad-attrs x)]
                                                     [(quad-attrs? x) x]
                                                     [(hashable-list? x) (quadattrs x)]
                                                     [else #f])) quads-or-attrs-or-lists))))