This section explains the mechanism for user-specified “tab stops” and the mechanisms that use and set them. The name “tab stops” is used because the feature is similar to that of the tab stops on a typewriter. The feature works by inserting an appropriate number of spaces and tab characters to reach the next tab stop column; it does not affect the display of tab characters in the buffer (see Usual Display). Note that the <TAB> character as input uses this tab stop feature only in a few major modes, such as Text mode. See Tab Stops.
This command inserts spaces or tabs before point, up to the next tab stop column defined by
tab-stop-list. It searches the list for an element greater than the current column number, and uses that element as the column to indent to. It does nothing if no such element is found.