Several additional variables control how Fortran indentation works:
Extra indentation within each level of ‘do’ statement (default 3).
Extra indentation within each level of ‘if’, ‘select case’, or
‘where’ statements (default 3).
Extra indentation within each level of ‘structure’, ‘union’,
‘map’, or ‘interface’ statements (default 3).
Extra indentation for bodies of continuation lines (default 5).
In Fortran 77, a numbered ‘do’ statement is ended by any statement
with a matching line number. It is common (but not compulsory) to use a
‘continue’ statement for this purpose. If this variable has a
non-nil value, indenting any numbered statement must check for a
‘do’ that ends there. If you always end ‘do’ statements with
a ‘continue’ line (or if you use the more modern ‘enddo’),
then you can speed up indentation by setting this variable to
nil. The default is nil.
If this is t, indenting an ‘endif’ (or ‘enddo’
statement moves the cursor momentarily to the matching ‘if’ (or
‘do’) statement to show where it is. The default is nil.
Minimum indentation for Fortran statements when using fixed form
continuation line style. Statement bodies are never indented less than
this much. The default is 6.
Minimum indentation for Fortran statements for tab format continuation line
style. Statement bodies are never indented less than this much. The
default is 8.
The variables controlling the indentation of comments are described in
the following section.