Version: 5.1.1
5 Contracts for struct type properties
This library is
unstable;
compatibility will not be maintained.
See
Unstable for more information.
Produces a contract for struct type properties. When the contract is
applied to a struct type property, it produces a wrapped struct type
property. When the wrapped struct type property is used to create a
new struct type (via
struct,
make-struct-type, etc),
it applies
value-contract to the value associated with the
property.
The contract has no effect on the struct type property accessor.
Examples: |
| | | | > (define (get-f s) ((prop-ref s) s)) | | > (define s1 (s add1)) | | > ((get-f s1) 5) | 6 | | > ((get-f s1) 'apple) | self-contract violation: expected <number?>, given: 'apple | contract on wrapped from (definition wrapped), blaming | (definition wrapped) | contract: | (struct-type-property/c | (-> any/c (-> number? number?))) | at: eval:3.0 | | > (define s2 (s (lambda (n) (if (zero? n) 'zero 'nonzero)))) | | > ((get-f s2) 5) | contract violation: expected <number?>, given: 'nonzero | contract on wrapped from (definition wrapped), blaming | top-level | contract: | (struct-type-property/c | (-> any/c (-> number? number?))) | at: eval:3.0 | | > ((get-f s2) 'apple) | self-contract violation: expected <number?>, given: 'apple | contract on wrapped from (definition wrapped), blaming | (definition wrapped) | contract: | (struct-type-property/c | (-> any/c (-> number? number?))) | at: eval:3.0 |
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