module Mail
grammar RFC2045
rule tspecials
"(" / ")" / "<" / ">" / "@" /
"," / ";" / ":" / '\\' / "<" / ">" /
"/" / "[" / "]" / "?" / "="
end
rule ietf_token
token+
end
rule custom_x_token
[xX] "-" token+
end
rule iana_token
token+
# <A publicly-defined extension token. Tokens # of this form must be registered with IANA # as specified in RFC 2048.>
end
rule token
[\x21-\x27] / # any (US-ASCII) CHAR
[\x2a-\x2b] / # except SPACE,
[\x2c-\x2e] / # CTLs,
[\x30-\x39] / # or tspecials
[\x41-\x5a] /
[\x5e-\x7e]
end
end
end