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malli 2024-09-27
how can I have values of multiple fields be generated with a shared generator function? for example, I have a data that looks like below.
[:map [:a int?] [:b int?] [:c int?]}
opqdonut 2024-09-27T05:29:27.482529Z
I think it's simplest to just add a :gen/gen to the :map and write the generator yourself
Yea but the generator has to generate values for separate keys at once. Otherwise the values will be generated independently
opqdonut 2024-09-27T05:37:56.027359Z
yes, that's why you attach it to the :map level, not the individual keys
Got it. Then how do I dispatch values to individual keys? Can you share an example?
opqdonut 2024-09-27T05:39:16.007879Z
you just generate the whole map at once
Aha will try that. So local dependency is propagated to global in this case.
opqdonut 2024-09-27T05:40:39.008009Z
user=> (mg/generate [:map {:gen/return {:a 1 :b 2 :c 3}} [:a :int] [:b :int] [:c :int]])
{:a 1, :b 2, :c 3}opqdonut 2024-09-27T05:43:01.487309Z
here's a real example:
opqdonut 2024-09-27T05:43:04.120029Z
user=> (mg/generate [:map {:gen/gen (gen/let [x gen/nat] (gen/return {:a x :b (inc x) :c (dec x)}))} [:a :int] [:b :int] [:c :int]])
{:a 9, :b 10, :c 8}opqdonut 2024-09-27T05:43:15.505779Z
(had to take a refresher in test.check)
Yea got it. Thanks!
to tweak a little, I could return nil (or whatever) for the second argument for gen/fmap, and use the first argument to return the data I want. In this case new data is generated whenever mg/generate is triggered.