Hi,
I was trying to come up with a naive implementation of check-expect/test and I
found out that if a macro expands to a set! on a module-level variable
directly, an error will be given when using the macro from another module. A
simple fix seems to instead have the macro to expands to a function call that
performs the set!.
I'm not sure what to think about it and I would like to hear why it works that
way or what I have missed.
Here's what I came up with in a few minutes :
(provide check-expect test)
(define tests '())
(define-syntax check-expect (λ (stx) (syntax-case stx () [(_ exp
res) #'(add-test (list (delay exp) res #'stx))])))
(define add-test (λ (test) (set! tests (cons test tests)))) ; add-test is
there because having check-expect expands to set! doesn't work when called from
another module.
(define test (λ () (printf "Ran ~a checks.\n" (length tests)) (let*
([failed (filter (λ (test) (not (equal? (force (car test)) (cadr test))))
(reverse tests))] [nbfailed (length failed)]) (if (> nbfailed
0) (begin (printf "~a tests failed:\n" nbfailed)
(for-each (λ (ft) (let ([ft-stx (caddr ft)])
(printf "Actual value ~a differs from ~a, the expected value.\n
~a\n" (force (car ft)) (cadr ft) (format "In ~a
at line ~a column ~a" (syntax-source ft-stx) (syntax-line ft-stx)
(syntax-column ft-stx))))) failed)) (printf "All test passed!\n"))
)))
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