On Wednesday, 8 April 2015 at 10:02:30 UTC, Sönke Ludwig wrote:
Am 08.04.2015 um 10:24 schrieb Andrea Fontana:
Any plan to support functions like these?
http://forum.dlang.org/thread/[email protected]?page=4#post-bcszdbasnjzmbwzdgeqy:40forum.dlang.org
There is opt() [1], which takes a path and returns a
`Nullable!JSONValue`. "get" is unfortunately already taken by
std.typecons.Algebraic, so we can't use it for its AA meaning.
Maybe another overload of opt?
JSONValue opt(JSONValue default_value, string[] path...);
[1]:
http://s-ludwig.github.io/std_data_json/stdx/data/json/value/json_value.opt.html
This seems a bit awkward to use. For example, it cannot handle
numeric indices. Could we instead have an `undefined` value, that
evaluates to `false` in a boolean context, and otherwise behaves
as if it were absent? The two `opIndex` overloads will again
return `undefined` for this value, as well as for non-objects and
non-arrays, and for non-existing elements. Then you could access
JSON values in an intuitive way without worrying about getting
Exceptions or even Errors:
writeln(json[42]["abc"][10 .. 20].get!int);
Only the `get` operation would throw if the type is wrong.
This also allows for easy and unambiguous testing whether an
object contains a key:
if(json["bla"] == JSONValue.undefined) { writeln("not
found"); }
Anyway, it needs to be made clear what the behaviour on
out-of-bounds or non-existing keys is: `undefined` value,
exception, error?
