|
|
#lang racket/base
|
|
|
(require "helper.rkt" racket/list)
|
|
|
(provide (all-defined-out))
|
|
|
|
|
|
#|
|
|
|
approximates
|
|
|
https://github.com/mbutterick/restructure/blob/master/src/Enum.coffee
|
|
|
|#
|
|
|
|
|
|
(define/post-decode (xenum-decode xe [port-arg (current-input-port)] #:parent [parent #f])
|
|
|
(define port (->input-port port-arg))
|
|
|
(parameterize ([current-input-port port])
|
|
|
(define index (decode (xenum-type xe)))
|
|
|
(or (list-ref (xenum-options xe) index) index)))
|
|
|
|
|
|
(define (xenum-size xe [val #f] #:parent [parent #f])
|
|
|
(size (xenum-type xe)))
|
|
|
|
|
|
(define/pre-encode (xenum-encode xe val [port-arg (current-output-port)] #:parent [parent #f])
|
|
|
(define port (if (output-port? port-arg) port-arg (open-output-bytes)))
|
|
|
(parameterize ([current-output-port port])
|
|
|
(define index (index-of (xenum-options xe) val))
|
|
|
(unless index
|
|
|
(raise-argument-error 'xenum-encode "valid option" val))
|
|
|
(encode (xenum-type xe) index)
|
|
|
(unless port-arg (get-output-bytes port))))
|
|
|
|
|
|
(struct xenum xbase (type options) #:transparent
|
|
|
#:methods gen:xenomorphic
|
|
|
[(define decode xenum-decode)
|
|
|
(define encode xenum-encode)
|
|
|
(define size xenum-size)])
|
|
|
|
|
|
(define (+xenum [type-arg #f] [values-arg #f]
|
|
|
#:type [type-kwarg #f]
|
|
|
#:values [values-kwarg #f])
|
|
|
(define type (or type-arg type-kwarg))
|
|
|
(unless (xenomorphic? type)
|
|
|
(raise-argument-error '+xenum "xenomorphic type" type))
|
|
|
(define values (or values-arg values-kwarg))
|
|
|
(unless (list? values)
|
|
|
(raise-argument-error '+xenum "list of values" values))
|
|
|
(xenum type values)) |