Is it possible to override a default spec generator so that data is always generated only for a single branch of the s/or composite spec?
(s/def ::x
(s/or :x-a nat-int?
:x-b string?))
(gen/sample (s/gen ::x))
;; generate strings only
You can use s/with-gen to supply a custom generator:
(s/def ::x
(s/with-gen
(s/or :x-a nat-int?
:x-b string?)
#(s/gen string?)))
(gen/sample (s/gen ::x))
=> ("" "j" "e" "Jmi" "" "d" "bc" "ul" "H65P0ni" "OEDK")
You could also use it only where you're sampling, without modifying the base ::x spec:
(gen/sample (s/gen (s/with-gen ::x #(s/gen string?))))
There are other spec functions that accept a map of overrides for the same purpose, e.g. s/exercise:
(s/exercise ::x 10 {::x #(s/gen string?)})
=>
(["" [:x-b ""]]
["" [:x-b ""]]
["" [:x-b ""]]
["" [:x-b ""]]
["13R0" [:x-b "13R0"]]
["7cT30" [:x-b "7cT30"]]
["uia0b" [:x-b "uia0b"]]
["" [:x-b ""]]
["bP" [:x-b "bP"]]
["4k2t6bW" [:x-b "4k2t6bW"]])