Decimal quotes will prevent this library from being used internationally for healthcare :( about jason HOT 12 CLOSED

With #115 merged, I believe all outstanding issues raised here have a way to be solved.

from jason.

@DarkMarmot I find myself in a similar situation that requires decimals in json to not be strings.
I have applied a similar solution to yours, but I loose the decimal places I had specified.

For example where I have Decimal.new("1000.00"), Jason returns it just 1000

Please do you have a solution for this?

Thanks

After having failed to get other parties to change their standards -- and seeing that libraries in other languages like C# support this functionality, I feel it's a real issue for Elixir to have a pretty "standard" library that doesn't have a way to support this.

If Jason doesn't move to do so, I will open source a fork of it that handles this (I had really wanted to avoid that route, but it seems like enough people need it that it should be out there).

The easiest hack I found to preserve the data (though, ideally, it should be configurable at parse I think) -- is to hack the library in decoder.ex, preserving floats at strings:

  defp try_parse_float(string, _token, _skip) do
    string
    #    :erlang.binary_to_float(string)
    #  catch
    #    :error, :badarg ->
    #      token_error(token, skip)
  end

I ended up needing to store an intermediate data format for my use case, which Jason happily supports with encoder protocols, e.g.:

defmodule MyProject.Decimal do
  defstruct value: nil

  def new(value) when is_binary(value) do
    %MyProject.Decimal{value: value}
  end
end

defimpl Jason.Encoder, for: MyProject.Decimal do
  def encode(decimal, _opts) do
    Decimal.to_string(Decimal.new(decimal.value), :normal)
  end
end

P.S. --Hopefully I haven't left something out. I did that a while ago and I'm having trouble doing code comparison because of mix format issues with special characters in the Jason lib from that time...

from jason.

Did you do manage to do it without forking?

What I meant is that I used Decimal.to_float() on my code, which was not that much of an inconvenience because I was doing some transform / data marshaling and not using the "jason data" straight.

So I didn't fork it because my use case was simpler and needed once (so far).

Yeah, I was building a library so I needed to support to/from JSON roundtrips with identical results. Having decoding options would really facilitate this for edge case needs I think.

from jason.

Nevermind -- I think I have a solution! :)

Using the helpful code from issue 71 -- one can wrap Decimal in a custom module to implement the protocol as an override! yay! :)

defimpl Jason.Encoder, for: FHIR.Decimal do
  def encode(decimal, _opts) do
    Decimal.to_string(decimal.decimal, :normal)
  end
end

from jason.

So, I found I needed to hack the Decoder a tiny bit in order to read numbers as strings (otherwise, numeric information is lost...)

I'd love to have this as an option (I know, a terrible and evil option) in Jason and would happily submit a PR if you're amenable.

Otherwise, I fear I'll have to create a fork to host a Lossless_Jason for everyone who's trapped with the aberrant horrors of "standards" like FHIR. :(

from jason.

P.S. I enjoyed digging through your code! lots of tricks and syntax I hadn't used before! :)

from jason.

Could be useful for some fields, like that (broken) new medical spec, for numbers to be read from and to Decimal instead of BEAM floats with a given option or new code path to call?

from jason.

Did you ever find a way to make it work?

edit: I made my own intermediary step with Decimal.to_float()

from jason.

Did you ever find a way to make it work?

edit: I made my own intermediary step with Decimal.to_float()

Yeah, I created a local fork of Jason that could handle it (it was only a one line change -- I still feel it would've been a nice config option as other libraries/languages do support it).

Did you do manage to do it without forking?

I brought it up with the FHIR community and ended up irritating a bunch of people :(

from jason.

@DarkMarmot I find myself in a similar situation that requires decimals in json to not be strings.
I have applied a similar solution to yours, but I loose the decimal places I had specified.

For example where I have Decimal.new("1000.00"), Jason returns it just 1000

Please do you have a solution for this?

Thanks

from jason.

Did you do manage to do it without forking?

What I meant is that I used Decimal.to_float() on my code, which was not that much of an inconvenience because I was doing some transform / data marshaling and not using the "jason data" straight.

So I didn't fork it because my use case was simpler and needed once (so far).

from jason.

It also appears that some work is going into this now. Wish this hadn't been denied as a feature back when... but hope:
#115

from jason.