Hello,
I’m having trouble getting the handin server to accept a BSL file that uses the
image library and also includes template definitions. I can make it work
separately. That is, I can accept BSL image program files as long as they don’t
have any templates and I can accept BSL programs with templates as long as they
don’t use images.
The problem is that when I go to require both 2htdp/image and
lang/htdp-beginner in the checker, there is a conflict with the image?
procedure being defined in both modules. Trying to use (except-in 2htdp/image
image?) inside the requires list doesn’t work.
What do I need to do to write a checker that will accept the student file shown
below?
My broken checker is included below. (The student file will also have
check-expects, which explains the presence of test-engine/racket-tests.)
Suzanne
––––––-––––––-––––––-––––––-––––––-
;; broken checker!
#lang s-exp handin-server/checker
(require handin-server/grading-utils)
(pre: (check-deadline))
(check: :language 'racket
:requires '(2htdp/image ;;; (except-in 2htdp/image image?)
test-engine/racket-tests
lang/htdp-beginner)
:create-text? #t
:textualize? #f
)
(post: #f)
;; Student file to be submitted
(require 2htdp/image)
;; template:
(define (process-strings strings)
(cond
[(empty? strings) ...]
[else (... (first strings) ...
(process-strings (rest strings)))]))
;; function based on template:
(define (make-color-chart colors)
(cond
[(empty? colors) empty-image]
[else (beside
(rectangle 30 100 "solid" (first colors))
(make-color-chart (rest colors)))]))
(check-expect (image-width (make-color-chart empty)) 0)
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