It’s missing Swift tests, but otherwise it’s a great post.
What even is a JSON number?
11–20 of 151 posts
Re: What even is a JSON number?
#12I tend to end up encoding everything as an integer (multiply by 1000, 10000 etc) and then turn it back into a float/decimal on decode. For instance if I am building a system dealing with dollar amounts I will store cent amounts everywhere, communicate cent amounts over the wire, etc. then treat it as a presentation concern to render it as a dollar amount.
Re: What even is a JSON number?
#13It's weird that any parser that loses digits is tolerated. A parser that forces strings into uppercase US-ASCII never would be.
Re: What even is a JSON number?
#14Since JSON is so widely used it should be modified to support more types - Mongo DB's Extended JSON supports all the BSON (Binary) types: Array Binary Date Decimal128 Document Double Int32 Int64 MaxKey MinKey ObjectId Regular Expression Timestamp https://www.mongodb.com/docs/manual/reference/mongodb-extend...
Much more valuable than any such extension would be a way to annotate types and byte lengths of keys and values so that parsers could work more efficiently. I’ve spent a lot of time making a fast JSON parser in Java and the thing that makes it so hard is you don’t know how many bytes anything is, or what type. It’s hard to do better than naive byte-by-byte parsing.
Re: What even is a JSON number?
#15It's weird that any parser that loses digits is tolerated. A parser that forces strings into uppercase US-ASCII never would be.
That's true for every floating point number in every programming language you have ever used, though.
$ python3
Python 3.10.13 (main, Aug 24 2023, 12:59:26) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 100000.000000000017
100000.00000000001Re: What even is a JSON number?
#16I tend to end up encoding everything as an integer (multiply by 1000, 10000 etc) and then turn it back into a float/decimal on decode. For instance if I am building a system dealing with dollar amounts I will store cent amounts everywhere, communicate cent amounts over the wire, etc. then treat it as a presentation concern to render it as a dollar amount.
This is great as long as you always make clear which value is pre post encoding. I remember one of my first production bugs was giving users 100 times the credit they actually bought. Oops.
Re: What even is a JSON number?
#17I tend to end up encoding everything as an integer (multiply by 1000, 10000 etc) and then turn it back into a float/decimal on decode. For instance if I am building a system dealing with dollar amounts I will store cent amounts everywhere, communicate cent amounts over the wire, etc. then treat it as a presentation concern to render it as a dollar amount.
I have tried to encode all non-trivial numbers as strings. If it's too big (or small), or if it's a float, I'll have to change my JSON schema. Bake the need to decode numbers into the transforms for consistency.
Re: What even is a JSON number?
#18It's weird that any parser that loses digits is tolerated. A parser that forces strings into uppercase US-ASCII never would be.
https://0.30000000000000004.com/
Although it would be good to move in the direction of using a BigDecimal equivalent by default when ingesting unknown data.
Re: What even is a JSON number?
#19I tend to end up encoding everything as an integer (multiply by 1000, 10000 etc) and then turn it back into a float/decimal on decode. For instance if I am building a system dealing with dollar amounts I will store cent amounts everywhere, communicate cent amounts over the wire, etc. then treat it as a presentation concern to render it as a dollar amount.
It's worth bearing in mind when you do that that the largest integer that is "generally safe" in JSON is 2^53-1, so if you scale by a factor of 10000 you're taking 13-14 more bits off that maximum. That leaves you about 2^40, or about a trillion, before you may start losing precision or seeing systems disagree about the decoded values. Whether that's a problem depends on your domain.
Re: What even is a JSON number?
#20It's weird that any parser that loses digits is tolerated. A parser that forces strings into uppercase US-ASCII never would be.
That's true for every floating point number in every programming language you have ever used, though. $ python3 Python 3.10.13 (main, Aug 24 2023, 12:59:26) [GCC 12.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>> 100000.000000000017 100000.00000000001
This is why Decimal exists:
Python 3.8.10 (default, Nov 22 2023, 10:22:35)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from decimal import Decimal
>>> Decimal('100000.000000000017')
Decimal('100000.000000000017')
>>> import json
>>> json.loads('{"a": 100000.000000000017}')
{'a': 100000.00000000001}
>>> json.loads('{"a": 100000.000000000017}', parse_float=Decimal)
{'a': Decimal('100000.000000000017')}