> On Feb 4, 2017, at 8:18 AM, Sourav Datta <soura.ja...@gmail.com> wrote:
>
> (require/typed "grammar1.rkt"
> [parse (->* (Listof Token)
> (Any)
> Syntax)])
>
> Type Checker: Type (->* (Listof Token) (Any) Syntax) could not be converted
> to a contract: required a flat contract but generated a chaperone contract
> in: (->* (Listof Token) (Any) Syntax)
>
> I am not sure what this means exactly but is this because Racket does not see
> the automatically exported function parse (or parse-tree) from a #lang brag
> module? And, is there a way to correct this error so that I can call the
> parse function from a TR module?
1) That type declaration for `parse` seems both too strict (in terms of the
input `parse` will accept), and not quite accurate in terms of order of
arguments. I might do it this way:
(require/typed brag/support
[#:opaque Token token-struct?]
[token (->* ((U String Symbol))
(Any
#:line Positive-Integer
#:column Natural
#:position Positive-Integer
#:span Natural
#:skip? Boolean)
Token)])
(define-type Tok (U String Symbol Token Void))
(require/typed "grammar1.rkt"
[parse (case-> ((U (Listof Tok) (-> Tok)) . -> . Any)
(Any (U (Listof Tok) (-> Tok)) . -> . Any))])
2) If I use `Any` rather than `Syntax` as the output type, then `parse` works.
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