These rules show a field meta-syntax, without regard for the particular type or internal syntax. Their purpose is to permit detection of fields; also, they present to higher-level parsers an image of each field as fitting on one line.
field = field-name ":" [ field-body ] CRLF
field-name = 1*<any CHAR, excluding CTLs, SPACE, and ":">
field-body = field-body-contents
[CRLF LWSP-char field-body]
field-body-contents =
<the ASCII characters making up the field-body, as
defined in the following sections, and consisting
of combinations of atom, quoted-string, and
specials tokens, or else consisting of texts>