The command C-c C-r (
fortran-column-ruler) shows a column
ruler momentarily above the current line. The comment ruler is two lines
of text that show you the locations of columns with special significance in
Fortran programs. Square brackets show the limits of the columns for line
numbers, and curly brackets show the limits of the columns for the
statement body. Column numbers appear above them.
Note that the column numbers count from zero, as always in GNU Emacs. As a result, the numbers may be one less than those you are familiar with; but the positions they indicate in the line are standard for Fortran.
The text used to display the column ruler depends on the value of
nil, then the value of the variable
fortran-column-ruler-fixed is used as the column ruler.
Otherwise, the variable
fortran-column-ruler-tab is displayed.
By changing these variables, you can change the column ruler display.
For even more help, use C-c C-w (
command which splits the current window horizontally, making a window 72
columns wide. By editing in this window you can immediately see when you
make a line too wide to be correct Fortran.