That seems an unfair criticism, most of that fdef is about the relationship between the args/return as opposed to just the types.

Perhaps. I was trying to find something pithy to give as an example. It's difficult to express all the things about spec that feel off to me. I'll try to enumerate some:

- verbosity (I think schema does this better https://github.com/plumatic/schema)

- because it tries to not be about validating types of inputs and outputs, and rather treats everything as predicates, it tends to live in a grey area between type validation and unit-testing, and I think hinders both

- it only helps at run-time

- over-abundance of macro-usage

I suspect what you consider a 'gray area', spec considers the whole point. What is the specification for this function? It has a signature and a return value and some behaviour in between. Spec verifies all of that together because it doesn't make sense to do it separately.

Also I'm not sure what you mean about run-time, you can and should use spec as part of your development workflow.

Other two points are totally fair though, and the macros are part of the reason it never got out of alpha before a rewrite.

Fair. I find that I naturally tend to think about the general properties of argument/return values and not just the types (or perhaps equivalently expand the meaning of "type" to encompass such usage) so I like the design, but I haven't yet used spec in anger and so might yet change my mind.

Hm the /amount/ of syntax isn't something I think about I guess, this being a Lisp.

I think they've taken the approach of making the system thorough and capable and this being a Lisp, we users can skin it with any level of shorthand that we please.

Datomic (the database from Cognitect) has a similar approach with its schema, which is quite verbose, but many folks that I know tend to simply write a function which spits out the schema, since it's 'just data'.

I tend to use Ghostwheel [1], but there's also spec-tools [2] and others.

[1]: https://github.com/gnl/ghostwheel

[2]: https://github.com/metosin/spec-tools

spec.alpha is implemented as a bunch of macros that make it difficult to work with spec forms as if they were "just data". This is one of the issues that spec-alpha2 tries to address [1].

Sure, you can import libraries to try to work around it but that's hardly ideal.

[1] https://github.com/clojure/spec-alpha2/wiki/Differences-from...

Schema is a pretty nice alternative: https://github.com/plumatic/schema