Docs delim section

[rofinn]

Since we're aiming for explicit delimiters we should probably have a section explaining some of the decisions.

1. Why do we need delimiters if keys should be tuples?

• NamedTuples need names to be symbols
• Dimension names are also represented by symbols

2. Why do we need multiple delimiters?

• To identify slightly different types of operations that may be important for code that automatically parses / tokenizes the results.
  • ⁻: Common identifier for flattening arbitrary nested structures
  • ˣ: Flattening dimensions of an array (new dimensions and keys are the product of the flattened dimensions)
  • ⁺: Arrays have been concatenated along that dimensions

[rofinn]

In retrospect, I wonder if we should avoid default delimiters altogether. We could default to using Tuples whenever possible to avoid having an opinion and require a delim argument be provided whenever it's required (e.g., NamedTuple, dimname). This has a few benefits.

1. Tuples preserve type information that can be used to generate stringified names after the fact
2. Erroring if delim isn't provide and is required provides means we don't need to have yet another separator debate. In practice we've also found that we usually want to provide a new dimname when flattening or concatenating keyed arrays anyways.