Sometimes it is necessary to use non-printable characters in a string or special characters such as the ‘ and ” that normally denote a string in IDL. It is easy to do so by referring to the correct byte presentation using the string() function.
For example to put in a tab: string(9B)
The apostrophe ‘: string(39B)
The quotation mark “: string(34B)
The other ASCII characters can be found here: http://en.wikipedia.org/wiki/ASCII – use the Dec. column