smallest float that can increment a given value

[casevh]

what would you pick for a name?

There is hint in his post,as he already has chosen names in gmpy2.
Also hi is the author🔨 of gmpy2.

gmpy2 uses the names next_above and next_below

I just used the same names as chosen by the MPFR library.

If I were to name a function that returns the increment (instead of functions that calculate the next, I would probably define it as float_increment(x, n) where x is the float and n is an integer specifying the direction (positive implies towards +Infinity and negative implies to -Infinity) and abs(n) specifies the number of steps to take.