_PRETEXT System Variable
Specifies a character expression to preface text merge lines.
Used with SET TEXTMERGE, you can merge text within a program. You can output lines of text, the contents of variables, and the results of expressions and functions to the screen, a window, a printer, a text file, or a low-level file.
If you store a character expression to _PRETEXT, the character expression is added to the beginning of the output text line. To facilitate program indentation, you can store a tab or tabs to _PRETEXT.