Replacements

[KodrAus]

Take another look at supporting simple replacements for serde::Serialize values. They can just be spliced in line.

This means json_str will depend on serde, but that's not the end of the world.

This kind of thing will be important for building json strings that aren't purely constant data.

[KodrAus]

Getting replacements into scope is probably going to be a nuisance, since the macro isn't seeing individual idents. It would be a bit crummy to have to add them into the macro like they were before.

[KodrAus]

So I'm thinking a json_fn macro could work, that would bind arguments in a closure that can be used as replacements:

let f = json_fn!(|qry: &str| {
    query: {
        query_string: $qry
    }
});

That will parse the given body until a replacement is found, parae its ident, and repeat until the end.

The result of the macro would be a closure that can be called with arguments and pushes each fragment onto a result string which is returned.

[KodrAus]

The arguments should just be str refs, and the caller can decide how that value is constructed. This means quoted strings will be a bit less ergonomic, but the idea is that you have control over whether or not the value is stringified. If serde is used then it'll handle this for you.