Messages customized based on input

[SevereOverfl0w]

I'd like to propose the possibility of looking at a new method of grabbing error messages where the metadata for the function is created dynamically, and therefore can take parameters. This would allow for more useful error messages, e.g. "%s must be at least 5 long" as opposed to "it should be longer"

To do this, I imagine the statically defined would need to be replaced with functions.

[theleoborges]

Thanks for raising this. It's been on my radar for a while but I haven't gotten to a solution I'm happy with. What would the public API look like?

[ghost]

I like the message-fn approach, but it doesn't help this use case. Considering the state-monad pattern the library uses in the validate fn, it makes sense to propagate it to validators too.

(defvalidator max-count
  [value maximum metadata]
  (if (<= (count (seq value)) maximum)
    [true nil]
    [false (format "%s should be less than %d characters"  (:key metadata) maximum)]))

(b/validate blog-post :headline [:max-count 50])

Or the messages could be made completely dynamic:

(defvalidator max-count
  [value maximum type metadata]
  (let [cnt (count (seq value))]
    (if (<= cnt maximum)
      [true nil]
      (cond
        (= :hard type) [false {:errors [(format "%s should be less than %d characters"  (:key metadata) maximum)]}]
        (= :soft type) [true {:warnings [(format "Consider shortening %s(%d characters) %s" (:key metadata) cnt (:reason metadata)]}]))))

(b/validate blog-post [:headline [:max-count 83 :hard]])
(b/validate blog-post [:headline [:max-count 83 :soft] {:reason "for better SEO." }])

[dLobatog]

I like @codepodu 's first approach here, returning a seq with [boolean possible-error-message] seems like the best approach. @LeonardoBorges have you looked at this lately?

[ghost]

I'd be happy to send a pull request if the community likes it. @dLobatog @LeonardoBorges

[armlesshobo]

late to the game, but I like the way this looks.

[ghost]

@LeonardoBorges What do you think?