fix nested maybes

[pravdomil]

fix billion-dollar mistake

elm-codec/tests/Base.elm

Line 266 in 0b09905

This is a known limitation: using null as Nothing and identity as Just means that nesting two maybes squashes Just Nothing with Nothing

[miniBill]

This is a backwards-incompatible change. I could consider merging if you created a new function, but changing the existing one is not possible without breaking existing Codecs

[pravdomil]

how the new function should be named?

[miniBill]

Eh... that's a tough call to be honest. The obvious maybe choice is already taken by the existing "collapsing/lenient/null" function.

I'm curious: why do you need a non-collapsing Maybe codec? The fact that you're using custom means that the format is not server-bound, so why not just creating a custom type better suited for your use case?

Like, in hindsight I should have probably called the function which is now maybe something like orNothing, or nullable or something, but the reason why I thought it was acceptable to collapse Just Nothing to Nothing is that... you should never have a Just Nothing in your model?

[pravdomil]

you should never have a Just Nothing in your model

Well you should not have Just Nothing in your model, but you can, so it can happen.

means that the format is not server-bound

A server bound? I'm using Elm on server side.

function which is now maybe something like orNothing, or nullable or something

What about:

• maybeWithoutNull
• maybeCustomType
• maybeType
• customMaybe
• justOrNothing
• betterMaybe

This is a backwards-incompatible change.

Or better rename current function to maybeLegacy then create a new version.
Then create function maybe a create new version.
Since it is a major version change people are forced to upgrade manually.

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BTW: this PR also fixes #9.

[pravdomil]

I would choose customMaybe or maybeType? What do you think?