This module is for reading and writing a common variation of character
separated data. The most common example is comma-separated. However
that is far from the only possibility, the same basic format is
exported by Microsoft products using tabs, colons, or other
characters.
The format is a series of rows separated by returns. Within each row
you have a series of fields separated by your character
separator. Fields may either be unquoted, in which case they do not
contain a double-quote, separator, or return, or they are quoted, in
which case they may contain anything, and will encode double-quotes by
pairing them. In Microsoft products, quoted fields are strings and
unquoted fields can be interpreted as being of various datatypes based
on a set of heuristics. By and large this fact is irrelevant in Perl
because Perl is largely untyped. The one exception that this module
handles that empty unquoted fields are treated as nulls which are
represented in Perl as undefined values. If you want a zero-length
string, quote it.
