Greetings!
A second, and my main reason for short names, or rather against long names, is that names should be to the point. None of the names
newPrimes topPrime doFactors doFilter
accurately describe the object they represent. The primes are not "new", the prime is not "on top". The "do" is a prefix does not carry a meaning either, it just conveys that doFactors has something to do with factors . This is best expressed by making doFactors a local definition in the where-block of factors.
Those remarks are fine with me! I asked about the stylistic changes because I came from the, hm, Java world and would like to avoid "writing familiar things in unfamiliar language". In Java, factors() and doFactors() would be a perfectly named methods: factors() is public, auxiliary doFactors() is private and essentially _does_ the factoring.
Out of curiosity, there is any reason why you called the auxiliary function 'go' ?
Convention. Often, an auxiliary function that does basically the same thing as the main function factors but with an extra parameter will be named factors' . The apostrophe has the drawback that it's easy to forget, so some people now name such auxiliary functions go instead.
I think having a local function 'go' in 'factors' is aboslutely plausible: it is local, there's no ambiguity. Regards, Sergey