Ok. I thought about what kinds of things might be different in the future with more understanding and experience using assertions...
How about this: Start an assert library with two exports, assert/higher-order and assert. Your research suggests that contracts are the only meaningful higher-order assertions, so this thing is assert/higher-order and the contract DSL is the right way to specify the condition. On the other hand, assert would be like the traditional one that using expressions. Another name for a/ho would be assert/contract which might be useful for using contracts for flat values. (The name though, only communicates mechanism and not the purpose like h-o.) Jay On Sun, Jun 1, 2014 at 6:14 PM, Robby Findler <ro...@eecs.northwestern.edu> wrote: > (I must have missed that suggestion, sorry.) > > I don't object to the sentiment behind the name, but I feel like we > have not figured out the best way to do assertions or invariants and > so we should leave such a valuable name for a future > contributor/insight and use the more "ugly" name for this one. > > Even if that name ends up in a different library, I wouldn't want an > assertion/invariant library to conflict with racket/contract. > > Robby > > > On Sun, Jun 1, 2014 at 6:57 PM, Matthias Felleisen <matth...@ccs.neu.edu> > wrote: >> >> I suggested exactly that name in a private message to Robby. >> >> >> >> On Jun 1, 2014, at 7:49 PM, Jay McCarthy wrote: >> >>> Based on this commit, I feel like "assert" would be a better name than >>> "invariant-assertion". I can imagine putting these on various internal >>> parts of a function where the self-blame would be justified. The >>> (define id (assert ctc e)) pattern is just one common use. >>> >>> Jay >>> >>> On Sat, May 31, 2014 at 1:46 PM, <matth...@racket-lang.org> wrote: >>>> matthias has updated `master' from 9d94ef725e to 89dea63995. >>>> http://git.racket-lang.org/plt/9d94ef725e..89dea63995 >>>> >>>> =====[ One Commit ]===================================================== >>>> Directory summary: >>>> 84.2% pkgs/racket-pkgs/racket-doc/scribblings/reference/ >>>> 11.0% racket/collects/racket/contract/private/ >>>> 4.6% racket/collects/racket/contract/ >>>> >>>> ~~~~~~~~~~ >>>> >>>> 89dea63 Matthias Felleisen <matth...@racket-lang.org> 2014-05-31 15:45 >>>> : >>>> | removed _contract_ language from _invariant-..._ as much as possible >>>> | >>>> | added a hint as to why the error message uses the inappropriate contract >>>> language >>>> : >>>> M racket/collects/racket/contract/private/base.rkt | 4 ++-- >>>> M racket/collects/racket/contract/region.rkt | 2 +- >>>> M .../scribblings/reference/contracts.scrbl | 22 >>>> ++++++++++---------- >>>> >>>> =====[ Overall Diff ]=================================================== >>>> >>>> pkgs/racket-pkgs/racket-doc/scribblings/reference/contracts.scrbl >>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> --- OLD/pkgs/racket-pkgs/racket-doc/scribblings/reference/contracts.scrbl >>>> +++ NEW/pkgs/racket-pkgs/racket-doc/scribblings/reference/contracts.scrbl >>>> @@ -1509,24 +1509,24 @@ The @racket[define-struct/contract] form only >>>> allows a subset of the >>>> (make-salmon #f 'pacific) >>>> ]} >>>> >>>> -@defform[(invariant-contract contract-expr expr)]{ >>>> - Establishes an invariant of @racket[expr], determined by >>>> @racket[contract-expr]. >>>> +@defform[(invariant-assertion invariant-expr expr)]{ >>>> + Establishes an invariant of @racket[expr], determined by >>>> @racket[invariant-expr]. >>>> >>>> - Unlike other ways to attach contracts to values, an >>>> - @racket[invariant-contract] does not establish a boundary >>>> - between two parties. Instead, it simply puts the contract >>>> - on the value, treating the module containing the >>>> - @racket[invariant-contract] expression as the party to be blamed >>>> - for any violations of the contract. >>>> + Unlike the specification of a contract, an >>>> + @racket[invariant-assertion] does not establish a boundary >>>> + between two parties. Instead, it simply attaches a logical assertion >>>> + to the value. Because the form uses contract machinery to check the >>>> + assertion, the surround module is treated as the party to be blamed >>>> + for any violations of the assertion. >>>> >>>> - This means, for example, that the contract is checked on >>>> + This means, for example, that the assertion is checked on >>>> recursive calls, when an invariant is used on the right-hand >>>> - side of a definition. >>>> + side of a definition: >>>> >>>> @examples[#:eval >>>> furlongs->feet-eval >>>> (define furlongss->feets >>>> - (invariant-contract >>>> + (invariant-assertion >>>> (-> (listof real?) (listof real?)) >>>> (λ (l) >>>> (cond >>>> >>>> racket/collects/racket/contract/private/base.rkt >>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> --- OLD/racket/collects/racket/contract/private/base.rkt >>>> +++ NEW/racket/collects/racket/contract/private/base.rkt >>>> @@ -3,7 +3,7 @@ >>>> (provide contract >>>> (rename-out [-recursive-contract recursive-contract]) >>>> current-contract-region >>>> - invariant-contract) >>>> + invariant-assertion) >>>> >>>> (require (for-syntax racket/base syntax/name syntax/srcloc) >>>> racket/stxparam >>>> @@ -89,7 +89,7 @@ >>>> (procedure-rename new-val vs-name)])] >>>> [else new-val]))) >>>> >>>> -(define-syntax (invariant-contract stx) >>>> +(define-syntax (invariant-assertion stx) >>>> (syntax-case stx () >>>> [(_ ctc e) >>>> (quasisyntax/loc stx >>>> >>>> racket/collects/racket/contract/region.rkt >>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> --- OLD/racket/collects/racket/contract/region.rkt >>>> +++ NEW/racket/collects/racket/contract/region.rkt >>>> @@ -4,7 +4,7 @@ >>>> define/contract >>>> with-contract >>>> current-contract-region >>>> - invariant-contract) >>>> + invariant-assertion) >>>> >>>> (require (for-syntax racket/base >>>> racket/struct-info >>> >>> >>> >>> -- >>> Jay McCarthy <j...@cs.byu.edu> >>> Assistant Professor / Brigham Young University >>> http://faculty.cs.byu.edu/~jay >>> >>> "The glory of God is Intelligence" - D&C 93 >> >> >> _________________________ >> Racket Developers list: >> http://lists.racket-lang.org/dev -- Jay McCarthy <j...@cs.byu.edu> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93 _________________________ Racket Developers list: http://lists.racket-lang.org/dev
