operator types: function

function:
    description:
        function operator
        an operator that has sequences as parameters, denoted: fn(seq1, seq2, seq3) input-seq
        the sequences are evaluated at invoke time, not definition time
        there are also context function operators, in which case the back end code also has access to the ContextList
        current code limitation is we only support up to 4 parameters
        bound functions are one way to get past this limitation

    examples:
        range(|1>, |5>, |0.5>)
            |1> + |1.5> + |2> + |2.5> + |3> + |3.5> + |4> + |4.5> + |5>

    see also:
        range, arithmetic