Creating struct-type properties with a struct-like interface.
(require struct-like-struct-type-property)(define-struct-like-struct-type-property name [field ...]
prop-option ...)
prop-option = #:property prop-expr val-exprDefines these identifiers:
prop:namenamename?name-field...
The property prop:name expects a function that takes a
"self" argument and returns a name result. When someone
wants to use the value as a prop:name, this function
should construct a more basic structure that contains the
field values.
Example:
(define-struct-like-struct-type-property foo [a b c])
> (foo-a (foo 1 2 3))
1
> (foo? (foo "a" "b" "c"))
#true
> (struct bar [x]
#:property prop:foo
(lambda (self)
(foo (first (bar-x self))
(second (bar-x self))
(third (bar-x self)))))
> (foo-a (bar (list 4 5 6)))
4
> (foo? (bar (list 'd 'e 'f)))
#true
> (match (bar (list 1 3 5))
[(foo a b c) c])
5The #:property prop-expr val-expr options specify
super-properties. Anything that implements prop:name will
automatically implement all the properties specified by the
given prop-exprs.
Example:
(define-struct-like-struct-type-property quadratic [a b c]
#:property prop:procedure
(λ (self x)
(+ (* (quadratic-a self) (sqr x))
(* (quadratic-b self) x)
(quadratic-c self))))
> (define f (quadratic 1 -2 -3))
> (f 0)
-3
> (f 1)
-4
> (f 2)
-3
> (f 3)
0
> (f 4)
5