Automatic indent for imported multiple-level lists

If items are preceded by tabs or spaces, indent the line, to create an outline format.. When interpreting spaces, you could evaluate the first line that starts with spaces, and set the criteria for the rest of the indents. For example, if the first indent is 4 spaces, then every time a line begins with spaces, each 4 spaces would be interpreted to mean "indent one level". 8 spaces is a 2-level indent. I'd round up, so if there are 5 spaces, I'd treat the same as 8 spaces. If 11 spaces, I'd treat it like 12, for 3 levels.
Then when importing or pasting a list into the app, the lines would be automatically indented outline-style.