I’m writing some code that parses floats, and one of the things it can parse, is
nan. In writing unit-tests for this code, I have need to write a value that contains
Float.nan and compare it to the result of this parser. Obviously, since
Float.nan is not equal to itself, the built-in equality won’t work. I have the equivalent of
ppx_deriving.eq [which today just uses equality for floats, hence also returns
false] and can modify it so that it checks if the first argument satisfies
Float.is_nan and if so then check if the second argument is also
Float.is_nan. Here’s my question:
Should I make this modification to the semantics of equality in
pa_ppx.deriving_plugins.eq? It seems like the purpose of these deriving plugins is for debugging, so that might be a good thing.
Maybe this special case should be driven by an option ? But lots of options is confusing, etc, etc.
So I’m looking for “advice about what the proper requirements for deriving.eq should be” really.
P.S. The code I’m writing is a YAML parser, and YAML can parse
nan, hence the need to write unit-tests to test this capability.