split function to split a string on a delimiter

[jdidion]

Array[String] split(String, String)

Splits the first argument (input) each time it encounters the second argument (pattern), where pattern is a POSIX ERE. This is the inverse of the sep function for a fixed pattern.

One impetus for this is to support deserialization of a delimited string to a string array.

Another option would be to add an optional second parameter to read_lines for the delimiter, which would default to \n.