Re: [racket-users] provide-if-not-defined
Thank you both. What I want is something closer to what Oak wrote, but that addresses only *checking*, whereas I also want the convenience of defining the module. So to use Oak's example, I want to be able to write #lang racket/base (provide-if-not-defined + - *) at the top of *all three files*, but in test-b.rkt, also write (provide [rename-out (my-+ +)]) So yes, if it turns out, say, `*` is not in racket/base, then all three files will indeed give me an error (at definition), like Oak's checker would. But this also reduces error by letting me duplicate the interface across files, while still being able to override parts of it, like in test-b.rkt, without producing an error that + is being exported twice. Shriram -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAJUf2yQ7L1p%3DSxeGzSt3WVKKYaNz0i9C8FgcRWs4z_otGZc_Wg%40mail.gmail.com.
Re: [racket-users] provide-if-not-defined
IIUC, that’s not what Shriram wants. He wants a kind of interface /
contract for a module (that it must export certain identifiers). The
solution that you posted makes the module satisfy the interface by
construction, but it creates another problem which is that he might
accidentally export a wrong identifier.
Wouldn’t create a test file suffice for detecting the original problem that
Shriram has, though? Something like this:
;; tester.rkt
#lang racket/base
(define required-ids '(+ - *))
(define files '("test-a.rkt" "test-b.rkt" "test-c.rkt"))
(define (error-handler e)
((error-display-handler) (exn-message e) e))
(for ([mod (in-list files)])
(parameterize ([current-namespace (make-base-namespace)])
(with-handlers ([exn:fail:syntax? error-handler])
(expand
`(module test racket/base
(require (only-in ,mod ,@required-ids)))
;; test-a.rkt
#lang racket/base
(provide + *)
;; test-b.rkt
#lang racket/base
(provide (rename-out [my-+ +]) - *)
(define (my-+ a b)
(+ a b 1))
;; test-c.rkt
#lang racket/base
(provide + -)
which produces:
only-in: identifier `-' not included in nested require spec in: "test-a.rkt"
only-in: identifier `*' not included in nested require spec in: "test-c.rkt"
On Wed, Sep 2, 2020, 1:12 PM Michael MacLeod
wrote:
> Does this example work: http://pasterack.org/pastes/95923?
>
> `if-not-defined` is written as a provide transformer which uses
> `syntax-local-module-defined-identifiers` to get the list of phase-0
> identifiers defined in the module.
>
> Best,
> Michael
>
> [code also pasted below]:
>
> #lang racket/base
>
> (module implementation racket/base
> (provide (if-not-defined "^my-"
>+ ; my-+ from this module
>- ; - from racket/base
>* ; my-* from this module
>/ ; / from racket/base
>))
>
> (require (for-syntax racket/base
>racket/provide-transform
>syntax/parse))
>
> (define-syntax if-not-defined
> (make-provide-transformer
> (lambda (stx modes)
>(syntax-parse stx
> [(_ pattern:string var:id ...)
> (define regex (regexp (syntax-e #'pattern)))
> (define phase-0-ids
> (hash-ref (syntax-local-module-defined-identifiers) 0))
> (define (find-id+sym v)
> (define v-string (symbol->string (syntax-e v)))
> (for/or ([id (in-list phase-0-ids)])
> (define id-string (symbol->string (syntax-e id)))
> (define maybe-match
> (and (string=? v-string
>(regexp-replace regex id-string ""))
> (not (string=? id-string v-string
> (if maybe-match
> (cons id
> (string->symbol v-string))
> #f)))
> (for/fold ([exports '()])
> ([v (in-list (syntax->list #'(var ...)))])
> (define maybe-id+sym (find-id+sym v))
> (cond [maybe-id+sym
>(cons (export (car maybe-id+sym)
> (cdr maybe-id+sym)
> 0
> #f
> (car maybe-id+sym))
> exports)]
> [else
>(cons (export v
> (syntax-e v)
> 0
> #f
> v)
> exports)]))]
>
> (define (my-+ a b)
> (+ a b 100))
>
> (define (my-* a b)
> (* a b 100)))
>
> (require 'implementation rackunit)
>
> (check-equal? (+ 2 3) 105)
> (check-equal? (- 2 3) -1)
> (check-equal? (* 2 3) 600)
> (check-equal? (/ 2 3) 2/3)
>
> --
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>
> .
>
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Re: [racket-users] provide-if-not-defined
Does this example work: http://pasterack.org/pastes/95923? `if-not-defined` is written as a provide transformer which uses `syntax-local-module-defined-identifiers` to get the list of phase-0 identifiers defined in the module. Best, Michael [code also pasted below]: #lang racket/base (module implementation racket/base (provide (if-not-defined "^my-" + ; my-+ from this module - ; - from racket/base * ; my-* from this module / ; / from racket/base )) (require (for-syntax racket/base racket/provide-transform syntax/parse)) (define-syntax if-not-defined (make-provide-transformer (lambda (stx modes) (syntax-parse stx [(_ pattern:string var:id ...) (define regex (regexp (syntax-e #'pattern))) (define phase-0-ids (hash-ref (syntax-local-module-defined-identifiers) 0)) (define (find-id+sym v) (define v-string (symbol->string (syntax-e v))) (for/or ([id (in-list phase-0-ids)]) (define id-string (symbol->string (syntax-e id))) (define maybe-match (and (string=? v-string (regexp-replace regex id-string "")) (not (string=? id-string v-string (if maybe-match (cons id (string->symbol v-string)) #f))) (for/fold ([exports '()]) ([v (in-list (syntax->list #'(var ...)))]) (define maybe-id+sym (find-id+sym v)) (cond [maybe-id+sym (cons (export (car maybe-id+sym) (cdr maybe-id+sym) 0 #f (car maybe-id+sym)) exports)] [else (cons (export v (syntax-e v) 0 #f v) exports)]))] (define (my-+ a b) (+ a b 100)) (define (my-* a b) (* a b 100))) (require 'implementation rackunit) (check-equal? (+ 2 3) 105) (check-equal? (- 2 3) -1) (check-equal? (* 2 3) 600) (check-equal? (/ 2 3) 2/3) -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CACehHmBAd%2BhNHsO3CkthY5ojuZ%2B_Rgj87rKbQrPXrAw5Fxcw7w%40mail.gmail.com.
