the errors that would be signalled by the body. also, remove
url-regexp from the exports (it was only recently added)
I believe this eliminates two of Eli's concerns:
- the contract is no longer so painful to read
- the performance is more reasonable.
Specifically, for the performance, here are the times I see to call
string->url on "http://www.racket-lang.org":
no contract: any/c
cpu time: 564 real time: 566 gc time: 3
weak contract: (-> (or/c string? bytes?) url?)
cpu time: 590 real time: 590 gc time: 3
strong, regexp-based contract:
(-> (or/c (not/c #rx"^([^:/?#]*):") #rx"^[a-zA-Z][a-zA-Z0-9+.-]*:") url?)
cpu time: 632 real time: 633 gc time: 5
This appears to be about a 10% slowdown for the regexp-based contract
over the weaker contract.
related to PR 12652
86572cc8c3