I took part of the goal to be that specs themselves would remain compatible, so an old set of specs wouldn't start failing on data that conforms to a new but compatible set of specs. That sort of compatibility isn't possible when you go from disallowing something to allowing it.
On Tuesday, November 14, 2017 at 10:15:23 AM UTC-6, Eric Normand wrote: > > Hey everybody! > > I'm chiming in after seeing this linked to in The Repl ( > https://therepl.net/). > > On Alex's suggestion, I rewatched Spec-ulation last night. The parts about > negation and evolution are towards the end. I was struck (once again) by > how clearly he picked apart changes. Relaxing a requirement is growth. And > adding requirements is breakage. But it left me with a question: > > Isn't disallowing a key and then allowing it (as optional) growth (instead > of breakage)? All of the old clients are still fine, and new clients can > use the key if they choose. You're relaxing the requirements. Taking the > opposite approach, I require some keys plus allow anything else. Some > clients will inevitably send me something with extra keys, which is okay, > they pass my specs. Later, I add in an optional key with a defined spec. So > I'm now restricting what used to be completely open. Isn't that breakage? I > feel like I'm seeing it exactly opposite as Rich Hickey. He says if you > disallow things, it's forever, because if you need to allow it later, > that's breakage. But there's not enough explanation for me to understand. > It seems like relaxing requirements. I feel like I'm missing something. In > short: why is it forever? > > He does mention is that logic engines don't have negation. Does this hint > that we will want to be using logic engines to reason over our specs? > > Thanks > Eric > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
