Convert::ytext converts strings to and from "ytext", a format inspired by xtext defined in rfc1894, the mime base64 and quoted-printable types (rfc 1394). the main goal is encode a utf8 string into something safe for use as the local part in an internet email address (rfc2822).

by default spaces are replaced with "+", "/" with "~", the characters "a-za-z0-9_.-" encode as themselves, and everything else is written "=ustr=" where ustr is the base64 (using "a-za-z0-9_." as digits) encoding of the unicode character code. the encoding is configurable (see below).