Editing Augmented Backus–Naur form (section)

==Terminal values==

[[Terminal symbol|Terminals]] are specified by one or more numeric characters.

Numeric characters may be specified as the percent sign <code>%</code>, followed by the base (<code>b</code> = binary, <code>d</code> = decimal, and <code>x</code> = hexadecimal), followed by the value, or concatenation of values (indicated by <code>.</code>). For example, a carriage return is specified by <code>%d13</code> in decimal or <code>%x0D</code> in hexadecimal. A carriage return followed by a line feed may be specified with concatenation as <code>%d13.10</code>.

Literal text is specified through the use of a string enclosed in quotation marks (<code>"</code>). These strings are case-insensitive, and the character set used is (US-)ASCII. Therefore, the string <code>"abc"</code> will match “abc”, “Abc”, “aBc”, “abC”, “ABc”, “AbC”, “aBC”, and “ABC”. [https://tools.ietf.org/html/rfc7405 RFC 7405] added a syntax for case-sensitive strings: <code>%s"aBc"</code> will only match "aBc". Prior to that, a case-sensitive string could only be specified by listing the individual characters: to match “aBc”, the definition would be <code>%d97.66.99</code>. A string can also be explicitly specified as case-insensitive with a <code>%i</code> prefix.