Creating a useful and funny python serializer

Hello markpickle

I got the name from ChatGPT.

Origin Story

I wanted an API to support as many mime types as possible. Some mime types are for the people, such as PDF, Excel/CSV. Some time types are for the machines, like json, bson.

I thought, what about HTML and text? HTML has a problem with XSS risks. Text has a problem of not having much of a standard story for "styled" plaintext. Except for Markdown. Can I use markdown as a mime type for what starts out as a JSON object?

Challenges

The app is two functions, loads and dumps and they take or return an Any type and take or return a string. The Any is a problem, because mypy doesn't know how to deal with arbitrarily complex types. It seems to get confused with Unions of Unions of Unions. It gets confused with generics, e.g. lists that can work with any contents.

Impedance Mismatches

Markdown has some analogies:

• header groupings + paragraphs make dicts, or even nested dicts
• Lists or lists of lists
• tables are dicts, but you can only put scalars in the values. This makes python objects of a certain level of nesting unrepresentable.
• strings and non-string types can be represented, but you can only infer a number should be integer. This blocks round tripping.

Some things are impossible

• empty dictionaries, empty lists exist in python but have no representation in markdown. An empty list is just zero-length whitespace where the list is not. This blocks round tripping.

Python has no use for a lot of markdown formatting, such as bold, or code block or quote. Those things would just be strings and they'd continue to hold markdown in the string.