Hi Siddhartha, Will this package handle ->* and ->i, either now or in the future?
On Sat, Aug 14, 2021 at 1:40 PM Siddhartha Kasivajhula <[email protected]> wrote: > Fellow Scheming Racketeers, > When you've written a function that takes an integer and returns another > one, you may write a contract for it as (-> integer? integer?). I want to > tell you about the social-contract > <https://docs.racket-lang.org/social-contract/index.html> package which > allows you to write it as (self-map/c integer?) instead. > > Why would the latter form be preferable? It isn't much less to type. But, > as we'll see, it is composable and it exploits the phrase structure of a > contract specification. Consider: > > (-> (-> integer? integer? integer?) (-> integer? integer? integer?))) > > With social-contract, this would be expressed as: > > (self-map/c (binary-composition/c integer?)) > > With a little familiarity, this tells you a lot, and saves you the trouble > of parsing the low level contract specification in order to understand what > this function does. > > And how about this: > (-> (-> any/c boolean?) sequence? sequence?) > > This becomes simply: > filter/c > > > *Who decides what "self map," "composition," and "filter" mean?* > We all do! In principle. The contracts available right now correspond to > well-known mathematical or programming ideas, but they could be anything at > all that we find to be common and useful. The "social" idea here is that, > through issues raised and discussed > <https://github.com/countvajhula/social-contract/issues> on the source > repo, we collectively agree on the forms and variations of useful high > level contracts. > > > *But wouldn't it be tedious to learn the social contract forms?* > On the contrary, it just might be fun. The package ships with C3PO, a > handy contract migration assistant that already knows both the Racket > contract DSL as well as the social contract forms, so you can provide > contracts you've already written and it will translate them into high-level > social contract representations. This can be useful for learning the new > forms in an interactive way, and can also greatly reduce the time it would > take to migrate any existing contracts you may have. > > Incidentally, C3PO is a "reverse compiler" implemented using parser > combinators (megaparsack > <https://docs.racket-lang.org/megaparsack/index.html>). It is "reverse" > in that it translates low-level contract specifications into high-level > ones, and may be a curiosity in its own right. You can learn more about it > here > <https://docs.racket-lang.org/social-contract/index.html#%28part._c3po%29> > and see its source here > <https://github.com/countvajhula/social-contract/tree/master/contract/social/c3po> > . > > Enjoy, > -Sid > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/racket-users/CACQBWFnUiaRZrO6jaGtOdyr1HxF%2BXn8aSovjC_VAaMHQtuHFxQ%40mail.gmail.com > <https://groups.google.com/d/msgid/racket-users/CACQBWFnUiaRZrO6jaGtOdyr1HxF%2BXn8aSovjC_VAaMHQtuHFxQ%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAE8gKofRhtH6LRMQLMMSpdWtAdysrw7mjqB%2BnMG%2BHoEy48MtLg%40mail.gmail.com.
