NB: More recent documentation for Dyalog APL is available at https://docs.dyalog.com/20.0/.
AutoIndent
This parameter specifies whether or not you want semi-automatic indenting during editing. The default value is 1. This means that when you enter a new line in a function, it is automatically indented by the same amount as the previous line. This option simplifies the entry of indented Control Structures.
See also Autoindent.