Suggestion: Add decode.number

[sbergen]

Context

Given that

1. the decode API is used with formats like JSON, where there is no distinction between floats and ints, and
2. the target (Erlang vs ES) is a somewhat leaky abstraction when it comes to handling numbers,

it can be confusing that on the Erlang target decode.float will not accept e.g. 1, but requires 1.0 to work properly.

Suggestion

Add decode.number: Decoder(Float), which would work equivalently to

decode.one_of(decode.float, or: [decode.int |> decode.map(int.to_float)])

This would both make it more convenient to decode formats where there's no distinction between ints and floats, and act as documentation about the context outlined above.

If this sounds like a good idea, I'd be happy to create a PR for it.

[lpil]

Could be good! The plan is to let the stdlib and the new decoder API settle for a while so we can see how people find it before making any changes.

[ethanthoma]

I also run into this issue. Sometimes JSON endpoints add a '.0' and sometimes they don't so I have to use the one_of func for it often