Am Sun, 03 Aug 2014 00:16:04 -0700 schrieb Andrei Alexandrescu <seewebsiteforem...@erdani.org>:
> We need a better json library at Facebook. I'd discussed with Sönke > the possibility of taking vibe.d's json to std but he said it needs > some more work. So I took std.jgrandson to proof of concept state and > hence ready for destruction: > > http://erdani.com/d/jgrandson.d > http://erdani.com/d/phobos-prerelease/std_jgrandson.html > > Here are a few differences compared to vibe.d's library. I think > these are desirable to have in that library as well: > > * Parsing strings is decoupled into tokenization (which is lazy and > only needs an input range) and parsing proper. Tokenization is lazy, > which allows users to create their own advanced (e.g. partial/lazy) > parsing if needed. The parser itself is eager. > > * There's no decoding of strings. > > * The representation is built on Algebraic, with the advantages that > it benefits from all of its primitives. Implementation is also very > compact because Algebraic obviates a bunch of boilerplate. Subsequent > improvements to Algebraic will also reflect themselves into > improvements to std.jgrandson. > > * The JSON value (called std.jgrandson.Value) has no named member > variables or methods except for __payload. This is so there's no > clash between dynamic properties exposed via opDispatch. > > Well that's about it. What would it take for this to become a Phobos > proposal? Destroy. > > > Andrei API looks great but I'd like to see some simple serialize/deserialize functions as in vibed: http://vibed.org/api/vibe.data.json/deserializeJson http://vibed.org/api/vibe.data.json/serializeToJson vibe uses UDAs to customize the serialization output. That's actually not json specific and therefore shouldn't be part of this module. But a simple deserializeJson which simply fills in all fields of a struct given a TokenStream is very useful and can be done without allocations (so it's much faster than going through the DOM). Nitpicks: * I'd make Token only store strings, then convert to double/number only when requested. If a user is simply skipping some tokens these conversions are unnecessary overhead. * parseString really shouldn't use appender. Make it somehow possible to supply a buffer to TokenStream and use that. (This way there's no memory allocation. If a user want to keep the string he has to .dup it). A BufferedRange concept might even be better, because you can read in blocks and reuse buffers.
