Will this help:
#lang typed/racket
(define-syntax (the stx)
(syntax-case stx ()
[(_ (define (f x) e))
(let ((capital-x (capitalize stx #'x)))
#`(begin
(: f (-> #,capital-x #,capital-x))
(define (f x)
e)))]))
(define-for-syntax (capitalize stx x)
(define x:str (symbol->string (syntax-e x)))
(datum->syntax stx (string->symbol (string-titlecase x:str))))
(define-type X Integer)
(the
(define (f x)
x))
(f 10)
(f 'a) ;; <-- type check fails, comment out
On Oct 7, 2014, at 2:38 PM, Jack Firth <jackhfi...@gmail.com> wrote:
> I read a tweet about someone wistfully wishing there was some sort of "the"
> operator in a typed non-parensy language such that one could write something
> like this:
>
> Customer someFunc(the customer) { ... }
>
> and have it mean:
>
> Customer someFunc(Customer customer) { ... }
>
> Basically, an operator to take care of the common case where the variable
> name is just the lower-camel-case form of the type. As a Racket fan, I wanted
> to see if I could do this with a macro in Typed Racket. After some mucking
> around I had a form that handled the syntax correctly, but I couldn't use it
> in typed racket because the type checker and type annotations run as macros
> *before* my macro expands. As I read further, it seems to be the case that
> macros in typed racket are a very thorny problem and an area of open
> research. So is it currently possible to implement a "the" operator like the
> one shown above in typed racket? And if so, how would it be done?
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