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#lang racket/base
( require " helper.rkt " racket/list )
( provide ( all-defined-out ) )
#|
approximates
https://github.com/mbutterick/restructure/blob/master/src/Enum.coffee
|#
( define ( 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 ] #:parent [ parent #f ] ) ( size ( xenum-type xe ) ) )
( define ( 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 ( type options ) #:transparent
#:methods gen:xenomorphic
[ ( define decode xenum-decode )
( define encode xenum-encode )
( define size xenum-size ) ] )
( define ( +xenum type [ options null ] )
( xenum type options ) )