On 10/29/20, William J. Bowman <w...@williamjbowman.com> wrote: > I'm considering implementing, maybe as a library or a pull-request to > racket/dict, contracts for (partially) specifying which keys exist in a > dictionary and a contract for the value on that key.
Great! Please make the contract error messages point out the bad key and bad value. The error messages from hash/dc are usually too big for me, and I end up moving my key-check and value-check contracts into a function that checks things one-by-one. (Maybe hash/dc can give better errors ... I never looked into a fix.) > I've got a quick prototype here: > > https://gist.github.com/wilbowma/7e97c8a38130c720568d008b288466f0 > > (dictof (id expr) ...) > A contract for a dictionary that contains exactly the keys id ... that map > to > values that satisfy the contracts expr ... (respectively). > > (rho-dictof (id expr) ...) > A contract for a dictionary that contains at least the keys id ... that > map to > values that satisfy the contracts expr ... (respectively). > > Before I start documenting and making it a thing, I thought I'd solicit > feedback. Two comments: 1. make these functions, not macros 2. make "at least" the default behavior for dictof, add an option to override (#:exact-keys?), and remove rho-dictof -- 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 racket-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/racket-users/CAFUu9R7SMK%2BfCxGDHGm_eu%2BmTfcZ%2BZdC4R_dMceg%2Bn6VyY8oXQ%40mail.gmail.com.
