Yes, by stomps on I mean replaces. And yes I’m looking for an operation on specs themselves. Essentially I want two different specs that share the majority of their keys, but have a different spec for one or two keys. If such a thing doesn’t exist I guess I can rework it so the commonanility is together in a shared spec, and merge that with the extra different keys… rather than trying to merge the replacement keys over the top.

I guess it’s just a little confusing that s/merge has different semantics WRT keys than merge - but I get why s/merge is like this. I guess I’m after an s/merge-keys for merging s/keys specs.

or maybe s/keys-merge would be a better name.

Having different semantics for the same key is generally a smell, unless your override is a subset (rather than a different set). I think there may be some new options in spec 2 but I’d say right now I would separate the non-different keys into one spec, then merge with different partial map specs as needed.

Thanks, I’d already done what you suggest… It’s 3rd party data — so I don’t get to define the keys… but yes the override is actually a subset. Also I’m not sure if this a smell or not; but the superset spec really just exists to represent “noise” that I don’t care about but have to ignore gracefully… I’m not using those specs as specs so much as I’m using the spec API as a way to write generators of noise I need to ignore not barf on. e.g. I have a spec :raw/Body representing all message bodys I should just skip over and a spec :specific/Body for ones I care about. I could use s/or to model this but Body is nested in some other specs e.g. a Message and essentially I don’t want to have to redefine all the intermediates. I think this is essentially similar to the “Maybe Not” problems.

well you can use s/and now to combine your generic spec and (when necessary) the more restrictive spec

so it doesn’t replace, but only the more precise thing will pass both

yeah I did consider that but how do you do so when the spec isn’t the root spec?

yeah, that’s tricky - you need to rebuild everything back to the root

this is the kind of thing that will be easier in the spec 2 select stuff

yeah

that was my feeling too

thanks for confirming my intentions were good, at least! 🙂

FWIW I have rebuilt to the root… and rearchitectured the commonality into another spec etc… so it’s not so bad this time 🙂

Thanks. You can do this - but this is not the effect I want. https://clojurians.slack.com/archives/C1B1BB2Q3/p1547804648581400?thread_ts=1547749697.578800&cid=C1B1BB2Q3

Ah, I thought Kenny’s question was independent from yours

dunno it may have been 🙂