ALPHA = %x41-5A / %x61-7A ; A-Z / a-z BIT = "0" / "1" CHAR = %x01-7F ; any 7-bit US-ASCII character, excluding NUL CR = %x0D ; carriage return CRLF = CR LF ; Internet standard newline CTL = %x00-1F / %x7F ; controls DIGIT = %x30-39 ; 0-9 DQUOTE = %x22 ; " (Double Quote) HEXDIG = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" HTAB = %x09 ; horizontal tab LF = %x0A ; linefeed LWSP = *(WSP / CRLF WSP) ; linear white space (past newline) OCTET = %x00-FF ; 8 bits of data SP = %x20 ; space VCHAR = %x21-7E ; visible (printing) characters WSP = SP / HTAB ; white space