Re: [racket-dev] A proposal for parametric opaque types in Typed Racket

2015-01-29 Thread Benjamin Greenman
This has bothered me too, but I've realized that I was on the wrong track. The string a and symbol 'b are not different types. A struct (Foo a 'b), or (list a 'b), is a homogeneous data structure of type (U String Symbol) just like Alexander said. This really upsets me -- I like the Hindley

Re: [racket-dev] Announcing Soft Contract Verification tool

2015-01-18 Thread Benjamin Greenman
On Sun, Jan 18, 2015 at 9:44 AM, Greg Hendershott wrote: Is there a similarly simple/standard way to disable contracts? I'd love a #lang like that. Never mind Tony Hoare's metaphor about sailing. For now, I'm attaching a small patch that'll disable contracts (as far

Re: [racket-dev] Announcing Soft Contract Verification tool

2015-01-15 Thread Benjamin Greenman
I tried writing a small program, but got stuck pretty early on. When I try verifying the divides? function below, the tool times out. What's happening? (module div racket (provide (contract-out [divides? (- positive? positive? boolean?)])) (define (positive? x) (and (integer? x) (= 0

[racket-dev] managing packages

2014-11-05 Thread Benjamin Greenman
I hear that Racket is having some trouble determining who broke what in the package ecosystem. I do not know the specifics of this problem, but there was a recent discussion on the OCaml mailing list about OPAM's method of tracking package compatibility that may be relevant: