On 10/29/20, William J. Bowman <[email protected]> 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 [email protected]. 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.
