More Complete Examples for Semigroup and Semiring Validation

[jkachmar]

I worked out some more complete examples of validations using the Semigroup and Semiring instances today. They're pretty opinionated, but I think having a more completely worked out example in the repository could help newcomers.

Right now they're in a separate repo here, but if this seems like something the maintainers would like, I can clean them up and put them into a proper PR.

[paf31]

I think it would be great to have an example project in this repo or in the README - thanks for putting this together!

It would be good to try to minimize the dependencies and code as much as possible, I think.

[jkachmar]

Yeah, the repo was a bit of a rabbit hole for me this weekend to get comfortable with the library 😅.

I'll pare some stuff back and try to PR an example repo soon.

I'm thinking an examples directory with a subdirectory for semigroup-validation and semiring-validation that would provide small, runnable examples that printed some successful/unsuccessful validation results to the console.

[jkachmar]

How does this look: https://github.com/jkachmar/purescript-validation/tree/feat/add-examples/examples/semigroup ?

If that's good, I can do something similar for Semiring and PR them both.

[chexxor]

Yeah, this library is frustrating af without a full-blown explanation of it.

It's questions like:

• How is different than using Either? (accumulating errors)
• Why one would want to accumulate errors?
• How is validation different than parsing? (parsing Foreign vs validating EmailFormattedString)
• Why not enforce a NonEmpty functor in the error side?
• How to build a big validator from small, reusable validators? (v1 <> v2 *> resultVal?)
• How to build small, reusable validators? (why use Unit as result?)
• What kinds of data types can a validator return? (String vs EmailFormattedString?)

Every time I use this library I get annoyed that I have to validateX someVal *> pure someVal, because someVal is duplicated, which is painful for me to see, and I hate using pure because for me it's a sign that I should just use map.

[hdgarrood]

#17 added examples for the Semigroup version.

[JordanMartinez]

Closed by #17?

[hdgarrood]

This should not be considered closed by #17; that PR only added examples for semigroup validation. Semiring validation is still lacking documentation (although personally, I still think it doesn't deserve to be in core and we should solve that part of the problem by just removing it).

[JordanMartinez]

So #27 would actually close this because it would no longer need to be documented.