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 > >
