3.4.5. QUOTED-STRINGS

Where permitted (i.e., in words in structured fields) quoted-strings are treated as a single symbol. That is, a quoted-string is equivalent to an atom, syntactically. If a quoted-string is to be "folded" onto multiple lines, then the syntax for folding must be adhered to. (See the "Lexical Analysis of Messages" section on "Folding Long Header Fields" above, and the section on "Case Independence" below.) Therefore, the official semantics do not "see" any bare CRLFs that are in quoted-strings; however particular parsing programs may wish to note their presence. For such programs, it would be reasonable to interpret a "CRLF LWSP-char" as being a CRLF which is part of the quoted-string; i.e., the CRLF is kept and the LWSP-char is discarded. Quoted CRLFs (i.e., a backslash followed by a CR followed by a LF) are also subject to rules of folding, but the presence of the quoting character (backslash) explicitly indicates that the CRLF is data to the quoted string. Stripping off the first following LWSP-char is also appropriate when parsing quoted CRLFs.