The string is a text data type specific to χ PROLOG. The maximum length of a string is 65535 bytes. A string is any sequence of characters surrounded by backwards quotes.

To insert a backwards quote character in a string use two adjacent backwards quote characters:

‘‘

The tilde character (~) is used within strings as an escape character. Tilde followed by a printable character in the range ’@’ to ’_’ is used to represent a control character. For example:

‘~I‘

The tilde character can also be followed by a three digit number representing the ASCII code of a character. This can be useful for inserting characters with an ASCII value greater than 127. To insert a tilde in a string use ~~. Examples

• ‘ Apple‘
• ‘ 123‘
• ‘ hello world‘
• ‘ ~Ibold~M~J‘
• ‘ ~065‘
• ‘ don‘ ‘ t care‘