NonEmpty Slist

[vrom911]

Create another data structure similar to NonEmpty implemented through the ordinary list. Something like this:

data SNonEmpty a = a :| Slist a

[chshersh]

@vrom911 Awesome idea! I think the Slist.NonEmpty module would be a great place for this data type 🙂

The :| constructor is taken by the NonEmpty, unfortunatately. But maybe we don't need fancy operators. I see two options: introduce something similar to Cons for ordinary lists, e.g. "non-empty" cons:

data SNonEmpty a = NCons a (Slist a)

Or maybe even use a record:

data SNonEmpty a = SNonEmpty
    { sNonEmptyHead :: a
    , sNonEmptyTail :: Slist a
    }

But I think we want to provide ergonomic pattern-matching, as probably most of the time we want to pattern-match like this:

case snelist of
    NCons x xs -> ...