Hello, This is version 6.5.0.5.
(define-syntax (define-tokens stx)
(syntax-case stx []
[(_ token
#:+ Token (extra ...)
#:with [[subtoken #:+ SubToken subrest ...] ...]
[id #:+ ID #:-> parent #:as Type rest ...] ...)
(with-syntax ([token->datum (format-id #'token "~a->datum" (syntax-e
#'token))]
[([id? id-datum] ...) (for/list ([<id> (in-list
(syntax->list #'(id ...)))])
(list (format-id <id> "~a?"
(syntax-e <id>))
(format-id <id> "~a-datum"
(syntax-e <id>))))])
#'(begin (struct: token : Token ([source : Any] [line : Natural]
[column : Natural]
[position : Natural]
[span : Natural] extra ...))
(struct: subtoken : SubToken subrest ...) ...
(define-token id #:+ ID #:-> parent #:as Type rest ...) ...
(define token->datum : (-> Token Datum)
(lambda [instance]
(cond [(id? instance) (id-datum instance)] ...
[else (assert (object-name instance)
symbol?)])))))]))
The following code is okay, however, if more definitions are added, then
the typechecking will refuse to terminate itself.
(define-tokens css-token
#:+ CSS-Token ()
#:with [[css:numeric #:+ CSS:Numeric css-token ([representation :
String])]
[css:number #:+ CSS:Number css:numeric ()]]
[css:bad #:+ CSS:Bad #:-> css-token #:as Datum]
[css:close #:+ CSS:Close #:-> css-token #:as Char]
[css:cd #:+ CSS:CD #:-> css-token #:as Symbol]
[css:match #:+ CSS:Match #:-> css-token #:as Char]
[css:ident #:+ CSS:Ident #:-> css-token #:as Symbol]
[css:url #:+ CSS:URL #:-> css-token #:as String]
[css:function #:+ CSS:Function #:-> css-token #:as Symbol])
The attachment contains the full example to run.
Thanks.
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infinite-typechecking.rkt
Description: Binary data
