Subject: bug#19809: 24.4; f90-beginning-of-subprogram wrong behavior with string continuation

From: Raul Laasner <[email-masked]>
Date: Sat, 7 Feb 2015 22:25:10 +0200

The functions f90-beginning-of-subprogram and f90-end-of-subprogram do not
work correctly if the source file contains lines which begin with the
correct keywords but in fact belong to a continued string. For instance, in
the following,

subroutine foo()
  print*, '&
       end subroutine foo'
  ! The cursor is here
end subroutine foo

f90-beginning-of-subprogram jumps past the line containing 'subroutine
foo()'. A similar example could be written for f90-end-of-subprogram. I
propose to put a small check of whether the previous line ended with an
ampersand into the F90 major mode source file:

--- f90.el    2015-02-07 16:50:56.210519581 +0200
+++ f90_new.el    2015-02-07 16:56:44.997174743 +0200
@@ -1619,6 +1619,14 @@
                 (looking-at "[ \t0-9]*\\(!\\|$\\|#\\)")))
     not-last-statement))

+(defsubst f90-test-string-continuation ()
+  "Return true if the the current is a string continuation."
+  (save-excursion
+    (beginning-of-line)
+    (backward-char)
+    (skip-chars-backward " ")
+    (string= (string (char-before)) "&")))
+
 (defun f90-beginning-of-subprogram ()
   "Move point to the beginning of the current subprogram.
 Return (TYPE NAME), or nil if not found."
@@ -1629,9 +1637,13 @@
                 (re-search-backward f90-program-block-re nil 'move))
       (beginning-of-line)
       (skip-chars-forward " \t0-9")
-      (cond ((setq matching-beg (f90-looking-at-program-block-start))
+      (cond ((and
+          (setq matching-beg (f90-looking-at-program-block-start))
+          (not (f90-test-string-continuation)))
              (setq count (1- count)))
-            ((f90-looking-at-program-block-end)
+            ((and
+          (f90-looking-at-program-block-end)
+          (not (f90-test-string-continuation)))
              (setq count (1+ count)))))
     (beginning-of-line)
     (if (zerop count)
@@ -1654,9 +1666,13 @@
                 (re-search-forward f90-program-block-re nil 'move))
       (beginning-of-line)
       (skip-chars-forward " \t0-9")
-      (cond ((f90-looking-at-program-block-start)
+      (cond ((and
+          (f90-looking-at-program-block-start)
+          (not (f90-test-string-continuation)))
              (setq count (1+ count)))
-            ((setq matching-end (f90-looking-at-program-block-end))
+            ((and
+          (setq matching-end (f90-looking-at-program-block-end))
+          (not (f90-test-string-continuation)))
              (setq count (1- count))))
       (end-of-line))
     ;; This means f90-end-of-subprogram followed by f90-start-of-subprogram

Best wishes,
Raul Laasner

-- 
Raul Laasner
Institute of Physics
University of Tartu
Ravila 14c, 50411, Estonia
e-mail: [email-masked]
cell: (+372)5182268