On 10/01/2012 06:29 PM, Sam Tobin-Hochstadt wrote:
On Mon, Oct 1, 2012 at 6:49 PM, Neil Toronto <neil.toro...@gmail.com> wrote:
#lang typed/racket
(: plus (Flonum Flonum -> Flonum))
(define (plus a b)
(+ a b))
(module provider racket
(require (submod ".."))
(provide inline-plus)
(define-syntax-rule (inline-plus a b) (plus a b)))
(require 'provider)
(inline-plus 1.2 2.3)
This program doesn't make sense -- the outer module depends on
'provider (see the `(require 'provider)`) but 'provider depends on the
outer module (that's what the inner `require` is doing). That's a
cycle, and not allowed, typed or untyped.
You're right, that's wrong. Well, wrong-ish. Modules try to give the
illusion of being evaluated top-to-bottom, but that apparently can't
hold here.
FWIW, here's something that does work, and does what I want:
#lang racket/base
;; Struct definition
(module typed-struct typed/racket/base
(struct: flonum-wrapper ([value : Flonum]) #:transparent)
(provide (struct-out flonum-wrapper)))
;; Macros
(module untyped-syntax racket/base
(require racket/flonum
(submod ".." typed-struct))
(provide fw+)
(define-syntax-rule (fw+ x-expr y-expr)
(let ([x x-expr] [y y-expr])
(cond [(not (flonum-wrapper? x))
(raise-argument-error 'fw+ "flonum-wrapper" 0 x y)]
[(not (flonum-wrapper? y))
(raise-argument-error 'fw+ "flonum-wrapper" 1 x y)]
[else
(flonum-wrapper (fl+ (flonum-wrapper-value x)
(flonum-wrapper-value y)))])))
)
;; Definitions that depend on macros
(module more-typed-struct typed/racket/base
(require (submod ".." typed-struct)
(submod ".." untyped-syntax))
(provide fwdbl)
(: fwdbl (flonum-wrapper -> flonum-wrapper))
(define (fwdbl x)
(fw+ x x)))
(require 'typed-struct
'untyped-syntax
'more-typed-struct)
(provide (all-from-out
(submod "." typed-struct) ; `submod' is necessary?
(submod "." untyped-syntax)
(submod "." more-typed-struct)))
The only bit that bothers me is the (begin (not (flonum-wrapper? x))
...) stuff left lying around after TR's optimizer eliminates the
branches in the expansions of `fw+'. IIRC, they cause futures to sync,
but I'm going to believe that they won't always - or will be optimized
away - just so I can have a decent solution to the typed macro problem.
Neil ⊥
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