Nice, convenient and idiomatic way to handle Maybe's

[chshersh]

I propose to add next operators in Universum to work with Maybe in even more nice way:

(?:) = flip fromMaybe  -- elvis operator

m !!: s = m ?: error s  -- unsafe elvis operator

(?.) = (>>=)  -- specialisation for Maybe

So it should be possible to write code like this one:

tail args?.head?.readMaybe ?: 0

[chshersh]

Also consider this (I'll just put it here):

https://twitter.com/Iceland_jack/status/883314861924593664

[vrom911]

@chshersh , I like (?:) option 💯
But I'm not sure that introducing the pattern for Maybe constructors would be great thing to do.. 🤔

[chshersh]

I don't think we need to have ?. operator. >>= is more common and known to people. Though, ?: looks idiomatic. We don't want to have partial functions in universum so I don't think we need to have :!!.