I wrote a JSON library

[w0rp]

I completely missed something out there. Namely, my reasons why I 
just didn't like the existing implementations enough. Overall, 
the other libraries are all very similar, so I don't have major 
complaints, just little ones.

For vibe.d, it's actually pretty close to what I wanted. My big 
objection is that I don't like the 'Undefined' types. I would 
rather experience runtime errors in those cases. I also have to 
pretty much depend on Vibe to use it, rather than just a JSON 
library. Aside from that, it's not far off from what I'm after.

For Libdjson, it uses classes to represent json types. That just 
seems very awkward to use, and that shouts out "unnecessary 
garbage creation" to me.

The standard library (std.json) seems to nail the parsing of 
JSON, but lacks the ability to write a JSON string to an output 
range, and doesn't really offer any conveniences for working with 
the JSON data structure itself. std.json, vibe.d, and my own 
representation of JSON are all very similar. They are tagged 
unions implemented with union {} and an enum. What makes vibe.d 
and my own library nice is all of the operator overloads, 
properties, and convenience functions.

Another issue with std.json is lack of pretty-printing, which 
both vibe.d and my own library address. (Mine has toJSON!4 and 
writeJSON!8 for a string indented by 4 characters and writing to 
an output range indented by 8 characters, respectively.)

So that's essentially my rationale. Overall, writing the library 
was mostly done because I found it to be a rather entertaining 
challenge for myself.