move JsonDecodeError type to separate package

[srghma]

this would allow composing https://github.com/garyb/purescript-codec-argonaut/ and this lib

e.g. the purescript-codec-argonaut JsonCodec where some part is derived using class machinery? would be cool

@garyb

[thomashoneyman]

I think if both codec-argonaut and argonaut-codecs use the same error type that it makes sense to move the error type into argonaut-core. Both libraries already depend on it. Then it can be shared and yes functions from both libraries could be used (though I don’t know how common that would be).

[srghma]

hm, it would be easier, but I would move it to the separate package, so that users could choose between different error types

the core was working fine without JsonDecodeError 🤔

[thomashoneyman]

Sorry about that, removed the label.

[srghma]

hi, @thomashoneyman, so what do you think: move error type to the argonaut-core OR create separate package argonaut-error?

[garyb]

There's some discussion here about options for the error type: #85 since I think the current closed sum isn't exactly perfect, but I don't know the best way forwards yet to supporting more stuff without just allowing arbitrary strings. I'm probably not going to make my library dependent on an external error type until I figure out what to do about that.