Modular•4mo ago

Quick and Dirty JSON parser

I hacked together a JSON parser. https://gist.github.com/mzaks/c1947212fd23ba010129d2f6b7c0fdfa As it is just a hack I will not even put it into a proper repo, but I think it might be useful as a learning exercise, or for some other hacks 🙂

Gist

Quick and Dirty JSON parser in Mojo

Quick and Dirty JSON parser in Mojo. GitHub Gist: instantly share code, notes, and snippets.

5 Replies

a2svior•4mo ago

Lessss gooooo JSON serialization in Mojo 🔥 I'm surprised how few lines of code is required to make a simple parser

Maxim•4mo ago

There are still a few special cases which are not covered, like scientific notation for numeric values, hex and escaping stuff. But generally this should be it. It is a slow implementation as I am duplicating Strings everywhere.

a2svior•4mo ago

@toasty has updated his great StringBuilder implementation to use recently introduced Spans, maybe that would be helpful?

Maxim•4mo ago

Best case scenario JSONValue has a reference to the initial string and start, stop indices. This way no copying needed. We still scan through the string a lot but we don’t need to copy it all the time. Also just realized there is a bug. [“a”, “]”, “b”] would not parse correctly. Will fix tomorrow. Now I am already on my📱. Or maybe someone else wants to take a stab at it? Updated the Gist with a more robust version of the parser and a few tests for the previous buggy cases like:

{ "a": [1, "]", 3]  }
[ [1, "]", 3]  ]
[ {"a": 1, "b": "}", "c": 3}  ]
{"first": {"a": 1, "b": "}", "c": 3}, "second" : true }

{ "a": [1, "]", 3]  }
[ [1, "]", 3]  ]
[ {"a": 1, "b": "}", "c": 3}  ]
{"first": {"a": 1, "b": "}", "c": 3}, "second" : true }

Three chickens in the green bag•4mo ago

I don’t doubt that with a little time and love that this could be pretty good

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Quick and Dirty JSON parser