f90-mode - auto-fill and font-lock

[Glenn Morris]

Hi,


Three issues (and two possible solutions) with f90.el as supplied with
Emacs 21.1.

(1) The e-mail address specified in the variable `bug-f90-mode' appears to
    be invalid.

(2) There is a bug in f90-mode's handling of auto-fill.

This was reported in this newsgroup in May 2000 but still exists. I guess
if Fortran was as sexy as C this wouldn't be the case, sigh. ;)

To reproduce it:

emacs -q --no-site-file

M-x f90-mode
M-x auto-fill-mode

Now type a long line, such that one is in the middle of a string (ie inside
'' quotes) when passing fill-column. One gets rows and rows of `&' inserted
until '(Variable binding depth exceeds max-specpdl-size)' puts an end to
it. It works OK if one is not inside a string. The problem is that the
function `f90-break-line' uses (newline) to insert a newline. But plain
(newline) without a numeric argument auto-fills the line if necessary, so
one gets into an infinite loop of filling. It does not happen when filling
on a non-string, because then the function `f90-find-breakpoint' is called
first to move point to a suitable position to break the line, which usually
carries it safely to the left of fill-column.

(3) A minor issue with font-locking. `module procedure' and all members of
    the variable `f90-procedures-re' are font-locked inside comments. So for
    example in this comment:

!!! Must use a big range (say 10000 or so) for this array.

the "range" gets fontified as if it were the intrinsic function called
range.

A very simple patch that seems to fix (2) and (3) is attached. Not sure if
the solution to the "module procedure" thing is any good.

Not much I can do about (1) I'm afraid! :)

Regards,


Glenn


PS. Blatant ingratiation - can I just take a moment to say that I *love*
Emacs 21! Thanks for all the hard work!


--- Patch for f90.el follows this line ---

--- f90.el.ORIG Sat Dec  1 19:14:16 2001
+++ f90.el      Sat Dec  1 19:15:55 2001
@@ -372,7 +372,8 @@
    '("\\<\\(program\\|call\\|module\\|subroutine\\|function\\|use\\)\\>[ 
\t]*\\(\\sw+\\)?"
      (1 font-lock-keyword-face) (2 font-lock-function-name-face nil t))
    ;; Special highlighting of "module procedure foo-list"
-   '("\\<\\(module[ \t]*procedure\\)\\>" (1 font-lock-keyword-face t))
+   '("\\<\\(module[ \t]*procedure\\)\\>"
+        (1 (if (f90-in-comment) font-lock-comment-face font-lock-keyword-face) 
t))
    ;; Highlight definition of new type
    '("\\<\\(type\\)[ \t]*\\(.*::[ \t]*\\|[ \t]+\\)\\(\\sw+\\)"
      (1 font-lock-keyword-face) (3 font-lock-function-name-face))
@@ -409,7 +410,7 @@
    (list
     f90-keywords-level-3-re
     f90-operators-re
-    (list f90-procedures-re '(1 font-lock-keyword-face t))
+       (list f90-procedures-re '(1 font-lock-keyword-face keep))
    "\\<real\\>"                        ; Avoid overwriting real defs.
    ))
   "Highlights all F90 keywords and intrinsic procedures.")
@@ -1472,14 +1473,14 @@
   (interactive)
   (let (ctype)
     (cond ((f90-in-string)
-          (insert "&") (newline) (insert "&"))
+          (insert "&") (newline 1) (insert "&"))
          ((f90-in-comment)
           (setq ctype (f90-get-present-comment-type))
-          (newline)
+          (newline 1)
           (insert ctype))
          (t (insert "&")
             (if (not no-update) (f90-update-line))
-            (newline)
+            (newline 1)
             (if f90-beginning-ampersand (insert "&")))))
   (f90-indent-line))