3.4.1. QUOTING

Some characters are reserved for special interpretation, such as delimiting lexical tokens. To permit use of these characters as uninterpreted data, a quoting mechanism is provided. To quote a character, precede it with a backslash ("\").

This mechanism is not fully general. Characters may be quoted only within a subset of the lexical constructs. In particular, quoting is limited to use within:

• quoted-string
• domain-literal
• comment

Within these constructs, quoting is REQUIRED for CR and "\" and for the character(s) that delimit the token (e.g., "(" and ")" for a comment). However, quoting is PERMITTED for any character.

Note: In particular, quoting is NOT permitted within atoms. For example when the local-part of an addr-spec must contain a special character, a quoted string must be used. Therefore, a specification such as:

                            Full\ Name@Domain

is not legal and must be specified as:

                            "Full Name"@Domain