Think about custom scalars that aren't strings

[tomhoule]

I am not clear on whether the spec allows that.

[tomhoule]

After a new reading it seems that yes, it is allowed (it just says that custom scalars should have a string representation, presumably for allowing embedding them into JSON).

What is the best way to allow for maximum flexibility there?

If we have a custom scalar called Bytes, we could generate type Bytes = Vec<u8>; (with an annotation on the struct to say what Bytes corresponds to).

I think it would probably be better to leave that out, and allow users to inject use statements inside the generated module directly, that way you would define your Bytes (or Date, for example) scalar in another module, and inject an import for it. This seems more flexible.

[tomhoule]

Relevant section from the spec: https://github.com/facebook/graphql/blob/master/spec/Section%203%20--%20Type%20System.md#scalars

[tomhoule]

apollo-codegen has that

  --passthroughCustomScalars                 Use your own types for custom scalars

https://github.com/apollographql/apollo-cli

[xtian]

There is also an RFC to allow the serialization type of a custom scalar to be defined: graphql/graphql-spec#326

[tomhoule]

We should definitely support that when it makes it into the spec, thanks for the link!

[tomhoule]

Custom target types for custom scalars are implemented in #74

[tomhoule]

This is implemented, let's move the discussion on the RFC to #75