Oops, some corrections to my original post.
On Monday, May 8, 2017 at 11:38:34 AM UTC-4, Dave Tenny wrote:
>
> Let's say I have a namespace that provides access to the database,
> say our table has these fields (as clojure specs)
>
> (s/def ::job-id nat-int?) ; 1 2 3 ...
> (s/def ::job-name string?) ; frobozz-executor
> (s/def ::job-status keyword?) ; :queued, :in-progress, :completed
>
>
> And that I have the logic in place to convert to/from the types (e.g.
> keywords).
>
> If I have a simple function to return records in from the jobs table it
> might look like:
>
> (s/def ::job-record (s/keys :req-un [::job-id ::job-name ::job-status]))
>
> (s/fdef get-jobs
> :args (s/cat :db database-handle?)
> :ret (s/coll-of ::job-record))
>
> (defn get-jobs
> [db]
> ... returns vector of maps, one for each record, jdbc-style ...)
>
> (get-jobs) => [{:job-id 1 :job-name "frobozz-executor" :job-status
> :queued} ...]
>
> Now here's where things get iffy in practice. Suppose I have other
> database interfaces that take similar but different maps or collections of
> keywords.
>
> For example, a function like this which lets you specify which fields you
> want retrieved:
>
> (s/fdef get-selective-jobs
> :args (s/cat :db database-handle? :fields (s/coll-of #{:job-id :job-name
> :job-status}))
>
:ret (s/coll-of (s/keys :opt-un [ ::job-id ::job-name ::job-status
])))
^^ correction of :fields above, additiobn of :ret
> (defn get-selective-jobs
> [db fields]
> ... return only fields from the database that are specified in the
> fields parameter ...)
>
>
> Once you start getting some similar-but-different specs, it'd be nice
> apply a bit of code building.
>
> e.g.
>
> (def job-field-keys [::job-id ::job-name ::job-status])
>
> (s/def ::job-record (s/keys* :req-un job-field-keys))
> (s/fdef get-selective-args
> :args (s/cat* :db database-handle? :fields (s/coll-of (set
> job-field-keys))
>
:ret (s/coll-of (s/keys* :opt-un job-field-keys)))
^^ correction to :args above, addition of :ret
> Hopefully this is conducive to some thought/discussion of the subject,
> and/or someone can just let me know how I should be doing this if there's
> an easy way in the present spec implementation.
>
The point being that it's be nice to have some easier ways of specifying
similar but different sets of data in
s/keys, s/cat, s/coll-of, and possibly other macros.
>
> Sidewise plea: inline specs for s/keys like you can do for s/cat. s/keys
> deliberate omision of inline specs does occasionally get in the way in
> large namespaces.
>
>
>
>
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