nealrichardson commented on issue #13803:
URL: https://github.com/apache/arrow/issues/13803#issuecomment-1206399291
The trouble is: what do you expect to do with this JSON? Round-trip and
re-create the Schema from the JSON? That gets tricky with things like nested
types, extension types, metadata, etc. It really becomes an Arrow specification
question, not a JSON serialization problem. As such, if you want to pursue it,
you should raise it on the dev mailing list. I seem to recall this idea coming
up in the past and it not getting much support, but maybe I misremember, or
maybe the times are different.
Naively, in R you can get a JSON string version of the Schema with some
manipulation. Here's an ugly base-R one-liner, just to illustrate:
```
> s
Schema
name: string
height: int32
mass: double
hair_color: string
skin_color: string
eye_color: string
birth_year: double
sex: string
gender: string
homeworld: string
species: string
films: list<item: string>
vehicles: list<item: string>
starships: list<item: string>
> cat(jsonlite::toJSON(setNames(lapply(s, function (x) x$type$ToString()),
s$names), pretty = TRUE, auto_unbox = TRUE))
{
"name": "string",
"height": "int32",
"mass": "double",
"hair_color": "string",
"skin_color": "string",
"eye_color": "string",
"birth_year": "double",
"sex": "string",
"gender": "string",
"homeworld": "string",
"species": "string",
"films": "list<item: string>",
"vehicles": "list<item: string>",
"starships": "list<item: string>"
}
```
But if you wanted to create a Schema from that, you're still in the world of
parsing things like `"list<item: string>"`.
On the R side, there is this nice code generating utility that Romain added
recently:
```
> s$code()
schema(name = utf8(), height = int32(), mass = float64(), hair_color =
utf8(),
skin_color = utf8(), eye_color = utf8(), birth_year = float64(),
sex = utf8(), gender = utf8(), homeworld = utf8(), species = utf8(),
films = list_of(utf8()), vehicles = list_of(utf8()), starships =
list_of(utf8()))
```
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