To Kill A Translationbird

[joedevivo]

If for some reason, you are overriding an existing schema with something particular for your project, you may have run into an edge case. If you need to override a translation, you're fine, but if a translation exists and you just need to remove it? You're out of luck... until now!

Now, you can do this:

{translation, 
 "some.key",
 fun(Conf) ->
   %% Do something to something and return translated value
}.

%% Oh no, that won't do at all
{translation, "some.key"}.

The second translation removes the first from the list and replaces it with an undefined function. It's important to note that if a third translation was added afterwards, it would override that deletion.

[joedevivo]

A fix for #79. This is a simple implementation that will ignore translations with undefined functions, and the ability to define those as {translation, Mapping}

I want to give a closer look at the stuff in PR #80 w.r.t to a better definition of the translation fun's API. Will dig in more later this week on that front.

cc: @Licenser

[seancribbs]

I see no problem with this, however I'm also not sure if it resolves #79. It allows the key to be ignored at schema-writing time, but not at config-parsing time.

[joedevivo]

@seancribbs this (https://github.com/basho/cuttlefish/commit/cafd9df2c7471dda24edb692154eb9439bdb4315#diff-e55ace98b9ea474b2b2bb3a984f6375cR69) is what makes it ignored at config-parsing time; it literally drops the existing one as it's read in.

[seancribbs]

Right, but i think what @Licenser meant was that a translation function could return a value that would prevent generation of the config entry. Overriding an existing translation in the schema doesn't accomplish that in the same way, you see?

[Licenser]

I actually tossed in a PR for that too. The issue is that sometimes a translation should not generate a value in the app.config since the mapping it reads from might not even be present (for example a optional mapping that needs to be translated if it exists).

[joedevivo]

Doesn't solve #79, but does solve some other edge case I thought #79 was. Merging 'cause @seancribbs said it was ok on mumble