On 8/4/14, 12:47 AM, Andrea Fontana wrote:
On my bson library I found very useful to have some methods to know if a
field exists or not, and to get a "defaulted" value. Something like:
auto assume(T)(Value v, T default = T.init);
Nice. Probably "get" would be better to be in keep with built-in hashtables.
Another good method could be something like xpath to get a deep value:
Value v = value["/path/to/sub/object"];
Cool. Is it unlikely that a value contains an actual slash? If so would
be value["path"]["to"]["sub"]["object"] more precise?
Moreover in my library I actually have three different methods to read a
value:
T get(T)() // Exception if value is not a T or not valid or value
doesn't exist
T to(T)() // Try to convert value to T using to!string. Exception if
doesn't exists or not valid
BsonField!T as(T)(lazy T default = T.init) // Always return a value
BsonField!T is an "alias this"-ed struct with two fields: T value and
bool error(). T value is the aliased field, and error() tells you if
value is defaulted (because of an error: field not exists or can't
convert to T)
So I can write something like this:
int myvalue = json["/that/deep/property"].as!int;
or
auto myvalue = json["/that/deep/property"].as!int(10);
if (myvalue.error) writeln("Property doesn't exists, I'm using default
value);
writeln("Property value: ", myvalue);
I hope this can be useful...
Sure is, thanks. Listen, would you want to volunteer a std.data.json
proposal?
Andrei
