From: "Linus Björnstam" <linus.internet@fastmail.se>
To: "Olivier Dion" <olivier.dion@polymtl.ca>, guile-user@gnu.org
Subject: Re: Contract programming in Guile
Date: Sat, 17 Jul 2021 18:29:07 +0200 [thread overview]
Message-ID: <bc6aee72-5a00-4b3f-8dbd-435104412568@www.fastmail.com> (raw)
In-Reply-To: <87tukthqu9.fsf@clara>
I wrote this a billion million years ago: https://hg.sr.ht/~bjoli/misc/browse/contract.scm?rev=tip
Very basic. Contracts are just syntax and not first-class objects.
--
Linus Björnstam
On Sat, 17 Jul 2021, at 18:01, Olivier Dion via General Guile related discussions wrote:
> Hi all,
>
> I'm a big fan of contract programming and was wondering if there's any
> SRFI or library that offers this in Guile?
>
> Here's an example of what I mean by contract:
> --------------------------------------------------------------------------------
> ;; Given
> (define (sum x y z)
>
> "Return the sum of X, Y and Z."
>
> (#:pre-conditions
> (>= x 0)
> (>= y 0)
> (>= z 0))
>
> (#:post-conditions
> (>= result 0))
>
> (+ x y z))
>
> ;; Would expand to something like
> (use-modules (ice-9 local-eval))
>
> (define (sum x y z)
>
> "
> Return the sum of X, Y, and Z.
>
> pre-conditions:
> (>= x 0)
> (>= y 0)
> (>= z 0)
>
> post-conditions:
> (>= result 0)
> "
>
> (for-each (lambda (condition)
> (unless (local-eval condition (the-environment))
> (begin
> (format #t "Failed pre-condition: ~a\n" condition)
> (exit 1))))
> '((>= x 0)
> (>= y 0)
> (>= z 0)))
>
> (let ((result (begin (+ x y z))))
> (for-each (lambda (condition)
> (unless (local-eval condition (the-environment))
> (begin
> (format #t "Failed post-condition: ~a\n" condition)
> (exit 1))))
> '((>= result 0)))
> result))
> --------------------------------------------------------------------------------
>
> --
> Olivier Dion
> PolyMtl
>
>
next prev parent reply other threads:[~2021-07-17 16:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-17 16:01 Contract programming in Guile Olivier Dion via General Guile related discussions
2021-07-17 16:29 ` Linus Björnstam [this message]
[not found] <mailman.57.1626624015.30702.guile-user@gnu.org>
2021-07-18 16:50 ` Kjetil Matheussen
2021-07-19 6:34 ` Linus Björnstam
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