f90: handle F2008 module function

* lisp/progmodes/f90.el (f90-font-lock-keywords-1)
(f90-looking-at-program-block-start):
Handle F2008 "module function" and subroutine.  (Bug#38415)
* test/lisp/progmodes/f90-tests.el (f90-test-bug38415): New test.

2 files changed, 32 insertions, 5 deletions

diff --git a/lisp/progmodes/f90.el b/lisp/progmodes/f90.el
index 92fba1c53bb..9f61b8a6fca 100644
--- a/lisp/progmodes/f90.el
+++ b/lisp/progmodes/f90.el
@@ -539,8 +539,10 @@ type-name parts, respectively."
 read\\|write\\)\\)[ \t]*(" (1 font-lock-keyword-face t))
    ;; Other functions and declarations.  Named interfaces = F2003.
    ;; F2008: end submodule submodule_name.
-   '("\\_<\\(\\(?:end[ \t]*\\)?\\(program\\|\\(?:sub\\)?module\\|\
-function\\|associate\\|subroutine\\|interface\\)\\|use\\|call\\)\
+   ;; F2008: module function|subroutine NAME.
+   '("\\_<\\(\\(?:end[ \t]*\\)?\\(program\\|\
+\\(?:module[ \t]*\\)?\\(?:function\\|subroutine\\)\\|\
+\\(?:sub\\)?module\\|associate\\|interface\\)\\|use\\|call\\)\
 \\_>[ \t]*\\(\\(?:\\sw\\|\\s_\\)+\\)?"
      (1 font-lock-keyword-face) (3 font-lock-function-name-face nil t))
    ;; F2008: submodule (parent_name) submodule_name.
@@ -1381,14 +1383,19 @@ write\\)[ \t]*([^)\n]*)")
   (cond
    ((looking-at "\\(program\\)[ \t]+\\(\\(?:\\sw\\|\\s_\\)+\\)\\_>")
     (list (match-string 1) (match-string 2)))
-   ((and (not (looking-at "module[ \t]*procedure\\_>"))
+   ((and (not (looking-at "module[ \t]*\\(procedure\\|function\\|subroutine\\)\\_>"))
          (looking-at "\\(module\\)[ \t]+\\(\\(?:\\sw\\|\\s_\\)+\\)\\_>"))
     (list (match-string 1) (match-string 2)))
    ((looking-at "\\(submodule\\)[ \t]*([^)\n]+)[ \t]*\\(\\(?:\\sw\\|\\s_\\)+\\)\\_>")
     (list (match-string 1) (match-string 2)))
-   ((and (not (looking-at "end[ \t]*\\(function\\|subroutine\\)"))
-         (looking-at "[^!'\"&\n]*\\(function\\|subroutine\\)[ \t]+\
+   ((and (not (looking-at "end[ \t]*\\(function\\|procedure\\|subroutine\\)"))
+         (looking-at "[^!'\"&\n]*\\(?:module[ \t]*\\)?\
+\\(function\\|subroutine\\)[ \t]+\
 \\(\\(?:\\sw\\|\\s_\\)+\\)"))
+    ;; TODO: In F2008  "module procedure foo" may or may not start a block,
+    ;; It is impossible to tell the difference without parsing state.
+;;;         (looking-at "[^!'\"&\n]*module[ \t]*\\(procedure\\)[ \t]+\
+;;;\\(\\(?:\\sw\\|\\s_\\)+\\)")))
     (list (match-string 1) (match-string 2)))))
 ;; Following will match an un-named main program block; however
 ;; one needs to check if there is an actual PROGRAM statement after
diff --git a/test/lisp/progmodes/f90-tests.el b/test/lisp/progmodes/f90-tests.el
index 540082c7174..b6fbac351dc 100644
--- a/test/lisp/progmodes/f90-tests.el
+++ b/test/lisp/progmodes/f90-tests.el
@@ -277,4 +277,24 @@ end program prog")
     (forward-line -2)
     (should (= 2 (current-indentation))))) ; type is
 
+(ert-deftest f90-test-bug38415 ()
+  "Test for https://debbugs.gnu.org/38415 ."
+  (with-temp-buffer
+    (f90-mode)
+    (setq-local f90-smart-end 'no-blink)
+    (insert "module function foo(x)
+real :: x
+end")
+    (f90-indent-line)
+    (should (equal " function foo"
+                   (buffer-substring (point) (line-end-position))))
+    (goto-char (point-max))
+    (insert "\nmodule subroutine bar(x)
+real :: x
+end")
+    (f90-indent-line)
+    (should (equal " subroutine bar"
+                   (buffer-substring (point) (line-end-position))))))
+
+
 ;;; f90-tests.el ends here