What defines a "Hexadecimal function"? Is it strictly a toHex function? Is .toString(16) banned? What about if the language implicitly outputs hexadecimal? (What about using xxd?)

If it’s a builtin function that takes in a base 10 number and outputs a number in base 16 as a string or whatever, it is banned. So both toHex and .toString(16) would be banned.

As for xxd, I would say that it does not apply in the context of this challenge, as it is used primarily to create or analyze the hexdumps of files.

The challenge says:

No built-in hexadecimal functions.

However, this comment thread suggests a stronger rule:

.toString(16) would be banned.

Since toString can convert to different bases depending on that argument, this suggests general base conversion functions are banned.

Please could you update the rules to make unambiguous whether general base conversion functions are permitted? This way the challenge will stand alone, not dependent on reading the comments for the correct interpretation.

Currently there is an answer which complies with the challenge wording which would be forbidden by the apparent exclusion of general base conversion functions in this comment thread.

Ambiguity is common when designing challenge specifications. For this reason I post my challenges first to the Sandbox category so as much ambiguity as possible can be pointed out before answers start arriving. This makes it easier to make changes to the rules without invalidating answers.

I've updated the ruleset in the question trichoplax‭ ATaco‭

trichoplax‭ I'll keep the idea of first posting to the Sandbox in mind.