string  re_split(string regex, string input, int maxsplits=0)
input string into substrings between matches of
maxsplits is given and not 0, it specifies the maximum number of splits to do.
NOTE: This does not match Python and other split methods as it behaves
differently with trailing delimiters.
a,b, will only split into two
strings. The regex string can be augmented with
|($(?!\s)) to split
three tokens. In VEX you frequently will need \\s. In a wrangle another
escape is needed and \\\\s is required.