The `make-primitive-class` function is a leftover from pre-v5.1 days, where the problem was to turn a C++ object into a Racket object. I'm not surprised that it has rotted away, it should be removed entirely, and I doubt that it's what you would want even if it worked.
At Thu, 17 Apr 2014 14:49:40 -0400 (EDT), dfel...@ccs.neu.edu wrote: > For a course project I've been working on adding generators to contracts for > use with contract-random-generate, and I've been trying to construct classes > and objects from simple object/c contracts. When trying to find a way to > functionally create a class at runtime, I came across the > `make-primitive-class` function in class-internal.rkt. > > This function is exported, and available at a plain racket repl, but has no > documentation that I have been able to find and the comments about it in > class-internal.rkt seem to be incorrect. > > Trying to call it from the repl has problems also, for example (ignoring for > a > moment that the arguments aren't of the expected types) > > -> (make-primitive-class #f #f 'foo object% null #f null null null null) > ; compose-class: arity mismatch; > ; the expected number of arguments does not match the given number > ; expected: 28 > ; given: 27 > > The definition is in terms of compose-class and is just missing a `null` > argument for the abstract-names, but even after fixing that in my local > branch > there is a discrepancy with the comments regarding it's first argument > `make-struct:prim`. > > ; The `make-struct:prim' function takes prop:object, a class, > ; a preparer, a dispatcher function, an unwrap property, > ; an unwrapper, and a property assoc list, and produces: > ; * a struct constructor (must have prop:object) > ; * a struct predicate > ; * a struct type for derived classes (mustn't have prop:object) > ; > ; The supplied preparer takes a symbol and returns a num. > ; > ; The supplied dispatcher takes an object and a num and returns a method. > ; > ; The supplied unwrap property is used for adding the unwrapper > ; as a property value on new objects. > ; > ; The supplied unwrapper takes an object and returns the unwrapped > ; version (or the original object). > ; > ; When a primitive class has a superclass, the struct:prim maker > ; is responsible for ensuring that the returned struct items match > ; the supertype predicate. > > This suggests that make-struct:prim should take 7 arguments, but passing a > function of 7 arguments to it from the repl produces: > > -> (make-primitive-class (lambda (a b c d e f g) (values #f #f #f)) #f 'foo > object% null #f null null null null) > ; #<procedure>: arity mismatch; > ; the expected number of arguments does not match the given number > ; expected: 7 > ; given: 5 > > Also as far as I can tell `make-primitive-class` is never used in the code > base, it is defined in class-internal.rkt, but can be commented out without > seeming to break anything else. Does anyone know if there is a purpose for > this > function, or if there is documentation somewhere on the functions I need to > pass it in order to construct a class. I think I'm starting to get a better > idea of how it might work from reading more of class-internal.rkt and how the > class* macro expands, but any guidance would be appreciated. > > Thanks > Dan > > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev _________________________ Racket Developers list: http://lists.racket-lang.org/dev
