compound context seq fn: such-that

such-that:
    description:
        such-that[op] seq
        filters the given sequence to those elements that return |yes> or |true> for op applied to that element
        it is less powerful than filter() but on the other hand, it should be faster

    examples:
        is-hungry |Fred> => |no>
        is-hungry |Sam> => |yes>
        is-hungry |Emma> => |yes>
        is-hungry |Liz> => |no>
        such-that[is-hungry] rel-kets[*]
            |Sam> + |Emma>

        such-that[is-prime] srange(|1>, |20>)
            |2> . |3> . |5> . |7> . |11> . |13> . |17> . |19>

    see also:
        filter