libmir / asdf

JSON library
http://asdf.libmir.org
Boost Software License 1.0
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How to implement a "before/after" diff of a json file #12

Open John-Colvin opened 3 years ago

John-Colvin commented 3 years ago

I want to find the difference between two json files of unknown structure, showing which entries have been added, changed and removed.

asdf.transform.AsdfNode has added and removed and that's part of the way to doing this, but actually not very convenient. Obviously I can write code to walk the AsdfNode tree by hand, but it seems like AsdfNode should be more helpful here as it's a common class of tasks

John-Colvin commented 3 years ago

should I be looking at mir-ion instead?

9il commented 3 years ago

Interesting. AsdfNode isn't good for that, Asdf number is actually a string.

We need a new type for that, like

import mir.algebraic: Nullable;
alias JsonNode = Nullable!(double, long, string, This[string], This[]);

or

import mir.algebraic: TaggedVariant;
alias TaggedJsonNode = TaggedVariant!(["null_", "float_", "integer", "string", "object", "array"],
    typeof(null), double, long, string, This[string], This[]);

Would RFC6902 work for you? For example, ruby implementation of JSON patch computation.

A possible API can look like

JsonNode jsonDiff(JsonNode from, JsonNode to)
{
    ...
}

This can be an independent algorithm from Asdf and Ion and we can implement conversion utilities between JsonNode and actual JSON backends.