The case expression is a convenient way to test a value against several discrete possibilities. The format is:
| (case | key |
| (values_1 expressions_1 ) | |
| ... | |
| (values_n expressions_n ) ) |
Each values_i is a list of values. The values_i are not evaluated, so symbols that are used as values should not be quoted. else may be used as a final key value that is always satisfied.
; Select kind of wine
(define (wine dish)
(case dish
((beef) 'red)
((chicken fish) 'white)
(else 'rose)) )
> (wine 'fish)
white
> (wine 'hot-dog)
rose