emacs/lisp/progmodes/fortran.el

;;; fortran.el --- Fortran mode for GNU Emacs

;; Copyright (c) 1986, 93, 94, 95, 97, 98, 99, 2000, 2001
;;   Free Software Foundation, Inc.

;; Author: Michael D. Prange <prange@erl.mit.edu>
;; Maintainer: Glenn Morris <gmorris@ast.cam.ac.uk>
;; Keywords: fortran, languages

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; This mode is documented in the Emacs manual.
;;
;; Note that it is for editing Fortran77 or Fortran90 fixed source
;; form.  For editing Fortran 90 free format source, use `f90-mode'
;; (f90.el).  It is meant to support the GNU Fortran language
;; implemented by g77 (its extensions to Fortran77 and
;; interpretations, e.g. of blackslash in strings).

;;; History:

;; Fortran mode was upgraded by Stephen A. Wood (saw@cebaf.gov).

;; We acknowledge many contributions and valuable suggestions by
;; Lawrence R. Dodd, Ralf Fassel, Ralph Finch, Stephen Gildea,
;; Dr. Anil Gokhale, Ulrich Mueller, Mark Neale, Eric Prestemon,
;; Gary Sabot and Richard Stallman.

;;; Code:

;; Todo:

;; * Tidy it all up (more)!
;; * Implement insertion and removal of statement continuations in
;;   mixed f77/f90 style, with the first `&' past column 72 and the
;;   second in column 6.
;; * Support any other extensions to f77 grokked by GNU Fortran I've missed.

(eval-when-compile			; silence compiler
  (defvar imenu-case-fold-search)
  (defvar imenu-syntax-alist))


(defgroup fortran nil
  "Major mode for editing fixed format Fortran code."
  :link  '(custom-manual "(emacs)Fortran")
  :group 'languages)

(defgroup fortran-indent nil
  "Indentation variables in Fortran mode."
  :prefix "fortran-"
  :group  'fortran)

(defgroup fortran-comment nil
  "Comment-handling variables in Fortran mode."
  :prefix "fortran-"
  :group  'fortran)


;;;###autoload
(defcustom fortran-tab-mode-default nil
  "*Default tabbing/carriage control style for empty files in Fortran mode.
A non-nil value specifies tab-digit style of continuation control.
A value of nil specifies that continuation lines are marked
with a character in column 6."
  :type  'boolean
  :group 'fortran-indent)

(defcustom fortran-tab-mode-string "/t"
  "*String to appear in mode line in TAB format buffers."
  :type  'string
  :group 'fortran-indent)

(defcustom fortran-do-indent 3
  "*Extra indentation applied to DO blocks."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-if-indent 3
  "*Extra indentation applied to IF blocks."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-structure-indent 3
  "*Extra indentation applied to STRUCTURE, UNION, MAP and INTERFACE blocks."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-continuation-indent 5
  "*Extra indentation applied to continuation lines."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-comment-indent-style 'fixed
  "*How to indent comments.
nil forces comment lines not to be touched;
`fixed' indents to `fortran-comment-line-extra-indent' columns beyond
  `fortran-minimum-statement-indent-fixed' (if `indent-tabs-mode' nil), or
  `fortran-minimum-statement-indent-tab' (if `indent-tabs-mode' non-nil);
`relative' indents to current Fortran indentation plus
  `fortran-comment-line-extra-indent'."
  :type  '(radio (const :tag "Untouched" nil) (const fixed) (const relative))
  :group 'fortran-indent)

(defcustom fortran-comment-line-extra-indent 0
  "*Amount of extra indentation for text within full-line comments."
  :type  'integer
  :group 'fortran-indent
  :group 'fortran-comment)

(defcustom fortran-comment-line-start "C"
  "*Delimiter inserted to start new full-line comment.
You might want to change this to \"*\", for instance."
  :version "21.1"
  :type    'string
  :group   'fortran-comment)

;; This used to match preprocessor lines too, but that messes up
;; filling and doesn't seem to be necessary.
(defcustom fortran-comment-line-start-skip
  "^[CcDd*!]\\(\\([^ \t\n]\\)\\2+\\)?[ \t]*"
  "*Regexp to match the start of a full-line comment."
  :version "21.1"
  :type    'regexp
  :group   'fortran-comment)

(defcustom fortran-directive-re
  "^[ \t]*#.*"
  "*Regexp to match a directive line.
The matching text will be fontified with `font-lock-keyword-face'.
The matching line will be given zero indentation."
  :version "21.4"
  :type    'regexp
  :group   'fortran-indent)

(defcustom fortran-minimum-statement-indent-fixed 6
  "*Minimum statement indentation for fixed format continuation style."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-minimum-statement-indent-tab (max tab-width 6)
  "*Minimum statement indentation for TAB format continuation style."
  :type  'integer
  :group 'fortran-indent)

;; Note that this is documented in the v18 manuals as being a string
;; of length one rather than a single character.
;; The code in this file accepts either format for compatibility.
(defcustom fortran-comment-indent-char " "
  "*Single-character string inserted for Fortran comment indentation.
Normally a space."
  :type  'string
  :group 'fortran-comment)

(defcustom fortran-line-number-indent 1
  "*Maximum indentation for Fortran line numbers.
5 means right-justify them within their five-column field."
  :type  'integer
  :group 'fortran-indent)

(defcustom fortran-check-all-num-for-matching-do nil
  "*Non-nil causes all numbered lines to be treated as possible DO loop ends."
  :type  'boolean
  :group 'fortran)

(defcustom fortran-blink-matching-if nil
  "*Non-nil causes \\[fortran-indent-line] on ENDIF to blink on matching IF.
Also, from an ENDDO statement blink on matching DO [WHILE] statement."
  :type  'boolean
  :group 'fortran)

(defcustom fortran-continuation-string "$"
  "*Single-character string used for Fortran continuation lines.
In fixed format continuation style, this character is inserted in
column 6 by \\[fortran-split-line] to begin a continuation line.
Also, if \\[fortran-indent-line] finds this at the beginning of a
line, it will convert the line into a continuation line of the
appropriate style. Normally $."
  :type  'string
  :group 'fortran)

(defcustom fortran-comment-region "c$$$"
  "*String inserted by \\[fortran-comment-region] at start of each \
line in region."
  :type  'string
  :group 'fortran-comment)

(defcustom fortran-electric-line-number t
  "*Non-nil causes line numbers to be moved to the correct column as typed."
  :type  'boolean
  :group 'fortran)

(defcustom fortran-column-ruler-fixed
  "0   4 6  10        20        30        40        5\
0        60        70\n\
\[   ]|{   |    |    |    |    |    |    |    |    \
\|    |    |    |    |}\n"
  "String displayed above current line by \\[fortran-column-ruler].
This variable is used in fixed format mode.
See the variable `fortran-column-ruler-tab' for TAB format mode."
  :type  'string
  :group 'fortran)

(defcustom fortran-column-ruler-tab
  "0       810        20        30        40        5\
0        60        70\n\
\[   ]|  { |    |    |    |    |    |    |    |    \
\|    |    |    |    |}\n"
  "String displayed above current line by \\[fortran-column-ruler].
This variable is used in TAB format mode.
See the variable `fortran-column-ruler-fixed' for fixed format mode."
  :type  'string
  :group 'fortran)

(defcustom fortran-analyze-depth 100
  "Number of lines to scan to identify fixed or TAB format style."
  :type  'integer
  :group 'fortran)

(defcustom fortran-break-before-delimiters t
  "*Non-nil causes filling to break lines before delimiters.
Delimiters are whitespace, commas, quotes, and operators."
  :type  'boolean
  :group 'fortran)

(defcustom fortran-mode-hook nil
  "Hook run when entering Fortran mode."
  :type  'hook
  :group 'fortran)


(defvar fortran-if-start-re "\\(\\(\\sw\\|\\s_\\)+:[ \t]*\\)?if[ \t]*("
  "Regexp matching the start of an IF statement.")

(defvar fortran-end-prog-re1
  "end\
\\([ \t]*\\(program\\|subroutine\\|function\\|block[ \t]*data\\)\\>\
\\([ \t]*\\(\\sw\\|\\s_\\)+\\)?\\)?"
  "Regexp possibly matching the end of a subprogram.")

(defvar fortran-end-prog-re
  (concat "^[ \t0-9]*" fortran-end-prog-re1)
  "Regexp possibly matching the end of a subprogram, from the line start.
See also `fortran-end-prog-re1'.")

(defconst fortran-type-types
  (concat "\\<"
          (mapconcat 'identity          ; " " -> "[ \t]*"
                     (split-string
                      (regexp-opt
                       (let ((simple-types
                              '("character" "byte" "integer" "logical"
                                "none" "real" "complex"
                                "double precision" "double complex"))
                             (structured-types '("structure" "union" "map"))
                             (other-types '("record" "dimension"
                                            "parameter" "common" "save"
                                            "external" "intrinsic" "data"
                                            "equivalence")))
                         (append
                          (mapcar (lambda (x) (concat "implicit " x))
                                  simple-types)
                          simple-types
                          (mapcar (lambda (x) (concat "end " x))
                                  structured-types)
                          structured-types
                          other-types)) 'paren))
                     "[ \t]*") "\\>")
  "Regexp matching Fortran types.")

(defvar fortran-font-lock-keywords-1
  ;; Program, subroutine and function declarations, plus calls.
  '(("\\<\\(block[ \t]*data\\|call\\|entry\\|function\\|\
program\\|subroutine\\)\\>[ \t]*\\(\\sw+\\)?"
     (1 font-lock-keyword-face)
     (2 font-lock-function-name-face nil t)))
  "Subdued level highlighting for Fortran mode.")

(defvar fortran-font-lock-keywords-2
  (append fortran-font-lock-keywords-1
          (list
           ;; Fontify all type specifiers (must be first - see below).
           (cons fortran-type-types 'font-lock-type-face)
           ;; Builtin keywords (except logical, do and goto - see below).
           (concat "\\<" (regexp-opt
                          '("continue" "format" "end" "enddo"
                            "if" "then" "else" "endif" "elseif"
                            "while" "inquire" "stop" "return"
                            "include" "open" "close" "read"
                            "write" "format" "print" "select" "case"
                            "cycle" "exit" "rewind" "backspace")
                          'paren) "\\>")
           ;; Builtin operators.
           (concat "\\." (regexp-opt
                          '("and" "or" "not" "lt" "le" "eq" "ge"
                            "gt" "ne" "true" "false")
                          'paren) "\\.")
           ;; do/goto keywords and targets, and goto tags.
           '("\\<\\(do\\|go *to\\)\\>[ \t]*\\([0-9]+\\)?"
             (1 font-lock-keyword-face)
             (2 font-lock-constant-face nil t))
           '("^ *\\([0-9]+\\)" . font-lock-constant-face)))
  "Medium level highlighting for Fortran mode.")

(defvar fortran-font-lock-keywords-3
  (append
   fortran-font-lock-keywords-1
   ;; All type specifiers plus their declared items.
   (list
    (list (concat fortran-type-types "[ \t(/]*\\(*\\)?")
          ;; Type specifier.
          '(1 font-lock-type-face)
          ;; Declaration item (or just /.../ block name).
          `(font-lock-match-c-style-declaration-item-and-skip-to-next
            ;; Start after any *(...) expression.
            (condition-case nil
                (and (match-beginning ,(1+ (regexp-opt-depth
                                            fortran-type-types)))
                     (forward-sexp)
                     (forward-sexp))
              (error nil))
            ;; No need to clean up.
            nil
            ;; Fontify as a variable name, functions fontified elsewhere.
            (1 font-lock-variable-name-face nil t))))
   ;; Things extra to `fortran-font-lock-keywords-3' (must be done first).
   (list
    ;; Goto-like `err=label'/`end=label' in read/write statements.
    '(", *\\(e\\(nd\\|rr\\)\\)\\> *\\(= *\\([0-9]+\\)\\)?"
      (1 font-lock-keyword-face) (4 font-lock-constant-face nil t))
    ;; Standard continuation character and in a TAB-formatted line.
    '("^ \\{5\\}\\([^ 0\n]\\)" 1 font-lock-string-face)
    '("^\t\\([1-9]\\)"         1 font-lock-string-face))
   `((,fortran-directive-re (0 font-lock-keyword-face t)))
   ;; `fortran-font-lock-keywords-2' without types (see above).
   (cdr (nthcdr (length fortran-font-lock-keywords-1)
                fortran-font-lock-keywords-2)))
  "Gaudy level highlighting for Fortran mode.")

;; Comments are real pain in Fortran because there is no way to
;; represent the standard comment syntax in an Emacs syntax table.
;; (We can do so for F90-style).  Therefore an unmatched quote in a
;; standard comment will throw fontification off on the wrong track.
;; So we do syntactic fontification with regexps.
(defvar fortran-font-lock-syntactic-keywords
  '(("^[cd\\*]" 0 (11))
    ("^[^cd\\*\t\n].\\{71\\}\\([^\n]+\\)" 1 (11)))
  "`font-lock-syntactic-keywords' for Fortran.
These get fixed-format comments fontified.")

(defvar fortran-font-lock-keywords fortran-font-lock-keywords-1
  "Default expressions to highlight in Fortran mode.")

(defvar fortran-imenu-generic-expression
  ;; These patterns could be confused by sequence nos. in cols 72+ and
  ;; don't allow continuations everywhere.
  (list
   (list
    nil
    ;; [This will be fooled by `end function' allowed by G77.  Also,
    ;; it assumes sensible whitespace is employed.]
    (concat
     ;; leading whitespace:
     "^\\s-+\\("
     ;; function declaration with optional type, e.g. `real',
     ;; `real*4', character(*), `double precision':
     "\\(\\sw\\|\\s-\\|[*()+]\\)*"
     "\\<function\\|subroutine\\|entry\\|block\\s-*data\\|program\\)"
     ;; Possible statement continuation:
     "[ \t" fortran-continuation-string "]+"
     ;; Variable to index:
     "\\(\\sw+\\)")
    3)
   ;; Un-named block data.
   '(nil "^\\s-+\\(block\\s-*data\\)\\s-*$" 1))
  "Value for `imenu-generic-expression' in Fortran mode.")


(defvar fortran-mode-syntax-table
  (let ((table (make-syntax-table)))
    ;; We might like `;' to be punctuation (g77 multi-statement
    ;; lines), but that screws abbrevs.
    (modify-syntax-entry ?\; "w"  table)
    (modify-syntax-entry ?\r " "  table)
    (modify-syntax-entry ?+  "."  table)
    (modify-syntax-entry ?-  "."  table)
    (modify-syntax-entry ?=  "."  table)
    (modify-syntax-entry ?*  "."  table)
    (modify-syntax-entry ?/  "."  table)
    (modify-syntax-entry ?\' "\"" table)
    (modify-syntax-entry ?\" "\"" table)
    ;; Consistent with GNU Fortran -- see the manual.
    (modify-syntax-entry ?\\ "\\" table)
    ;; This might be better as punctuation, as for C, but this way you
    ;; can treat floating-point numbers as symbols.
    (modify-syntax-entry ?.  "_"  table) ; e.g. `a.ne.b'
    (modify-syntax-entry ?_  "_"  table)
    (modify-syntax-entry ?$  "_"  table) ; esp. VMSisms
    (modify-syntax-entry ?\! "<"  table)
    (modify-syntax-entry ?\n ">"  table)
    table)
  "Syntax table used in Fortran mode.")

(defvar fortran-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map ";"        'fortran-abbrev-start)
    (define-key map "\C-c;"    'fortran-comment-region)
    (define-key map "\M-;"     'fortran-indent-comment)
    (define-key map "\M-\n"    'fortran-split-line)
    (define-key map "\M-\C-q"  'fortran-indent-subprogram)
    (define-key map "\C-c\C-w" 'fortran-window-create-momentarily)
    (define-key map "\C-c\C-r" 'fortran-column-ruler)
    (define-key map "\C-c\C-p" 'fortran-previous-statement)
    (define-key map "\C-c\C-n" 'fortran-next-statement)
    (define-key map "\C-c\C-d" 'fortran-join-line) ; like f90
    (define-key map "\M-^"     'fortran-join-line) ; subvert delete-indentation
    (define-key map "0" 'fortran-electric-line-number)
    (define-key map "1" 'fortran-electric-line-number)
    (define-key map "2" 'fortran-electric-line-number)
    (define-key map "3" 'fortran-electric-line-number)
    (define-key map "4" 'fortran-electric-line-number)
    (define-key map "5" 'fortran-electric-line-number)
    (define-key map "6" 'fortran-electric-line-number)
    (define-key map "7" 'fortran-electric-line-number)
    (define-key map "8" 'fortran-electric-line-number)
    (define-key map "9" 'fortran-electric-line-number)

    (easy-menu-define fortran-menu map "Menu for Fortran mode."
      `("Fortran"
        ["Manual" (info "(emacs)Fortran")]
        ("Customization"
         ,(custom-menu-create 'fortran)
         ["Set"  Custom-set t]
         ["Save" Custom-save t]
         ["Reset to Current" Custom-reset-current t]
         ["Reset to Saved"   Custom-reset-saved t]
         ["Reset to Standard Settings" Custom-reset-standard t]
         )
        "--"
        ["Comment Region" fortran-comment-region mark-active]
        ["Uncomment Region"
         (fortran-comment-region (region-beginning) (region-end) 1)
         mark-active]
        ["Indent Region"     indent-region mark-active]
        ["Indent Subprogram" fortran-indent-subprogram t]
        "--"
        ["Beginning of Subprogram" fortran-beginning-of-subprogram t]
        ["End of Subprogram"       fortran-end-of-subprogram       t]
        ("Mark"
         ["Subprogram" mark-defun      t]
         ["IF Block"   fortran-mark-if t]
         ["DO Block"   fortran-mark-do t]
         )
        ["Narrow to Subprogram" narrow-to-defun t]
        ["Widen" widen t]
        "--"
        ["Temporary column ruler" fortran-column-ruler  t]
        ["72-column window"       fortran-window-create t]
        ["Full Width Window"
         (enlarge-window-horizontally (- (frame-width) (window-width)))
         (< (window-width) (frame-width))]
        ["Momentary 72-column window" fortran-window-create-momentarily t]
        "--"
        ["Break Line at Point"    fortran-split-line t]
        ["Join Line"              fortran-join-line  t]
        ["Fill Statement/Comment" fill-paragraph     t]
        "--"
        ["Toggle auto-fill"   auto-fill-mode :selected auto-fill-function
         :style toggle]
        ["Toggle abbrev-mode" abbrev-mode    :selected abbrev-mode
         :style toggle]
        ["Add imenu Menu" imenu-add-menubar-index
         :active   (not (lookup-key (current-local-map) [menu-bar index]))
         :included (fboundp 'imenu-add-to-menubar)]))
    map)
  "Keymap used in Fortran mode.")


(defvar fortran-mode-abbrev-table
  (let (abbrevs-changed)
    (define-abbrev-table 'fortran-mode-abbrev-table nil)
    ;; Use the 6th arg (SYSTEM-FLAG) of define-abbrev if possible.
    ;; Only use `apply' to quieten the byte-compiler.
    (mapcar
     (function (lambda (element)
                 (condition-case nil
                     (apply 'define-abbrev fortran-mode-abbrev-table
                            (append element '(nil 0 t)))
                   (wrong-number-of-arguments
                    (apply 'define-abbrev fortran-mode-abbrev-table
                           (append element '(nil 0)))))))
     '((";au"   "automatic"         )
       (";b"    "byte"              )
       (";bd"   "block data"        )
       (";ch"   "character"         )
       (";cl"   "close"             )
       (";c"    "continue"          )
       (";cm"   "common"            )
       (";cx"   "complex"           )
       (";df"   "define"            )
       (";di"   "dimension"         )
       (";do"   "double"            )
       (";dc"   "double complex"    )
       (";dp"   "double precision"  )
       (";dw"   "do while"          )
       (";e"    "else"              )
       (";ed"   "enddo"             )
       (";el"   "elseif"            )
       (";en"   "endif"             )
       (";eq"   "equivalence"       )
       (";ew"   "endwhere"          )
       (";ex"   "external"          )
       (";ey"   "entry"             )
       (";f"    "format"            )
       (";fa"   ".false."           )
       (";fu"   "function"          )
       (";g"    "goto"              )
       (";im"   "implicit"          )
       (";ib"   "implicit byte"     )
       (";ic"   "implicit complex"  )
       (";ich"  "implicit character")
       (";ii"   "implicit integer"  )
       (";il"   "implicit logical"  )
       (";ir"   "implicit real"     )
       (";inc"  "include"           )
       (";in"   "integer"           )
       (";intr" "intrinsic"         )
       (";l"    "logical"           )
       (";n"    "namelist"          )
       (";o"    "open"              )   ; was ;op
       (";pa"   "parameter"         )
       (";pr"   "program"           )
       (";ps"   "pause"             )
       (";p"    "print"             )
       (";rc"   "record"            )
       (";re"   "real"              )
       (";r"    "read"              )
       (";rt"   "return"            )
       (";rw"   "rewind"            )
       (";s"    "stop"              )
       (";sa"   "save"              )
       (";st"   "structure"         )
       (";sc"   "static"            )
       (";su"   "subroutine"        )
       (";tr"   ".true."            )
       (";ty"   "type"              )
       (";vo"   "volatile"          )
       (";w"    "write"             )
       (";wh"   "where"             )))
    fortran-mode-abbrev-table))



;;;###autoload
(defun fortran-mode ()
  "Major mode for editing Fortran code in fixed format.
For free format code, use `f90-mode'.

\\[fortran-indent-line] indents the current Fortran line correctly.
Note that DO statements must not share a common CONTINUE.

Type ;? or ;\\[help-command] to display a list of built-in abbrevs for\
 Fortran keywords.

Key definitions:
\\{fortran-mode-map}

Variables controlling indentation style and extra features:

`comment-start'
  To use comments starting with `!', set this to the string \"!\".
`fortran-do-indent'
  Extra indentation within DO blocks (default 3).
`fortran-if-indent'
  Extra indentation within IF blocks (default 3).
`fortran-structure-indent'
  Extra indentation within STRUCTURE, UNION, MAP and INTERFACE blocks.
  (default 3)
`fortran-continuation-indent'
  Extra indentation applied to continuation statements (default 5).
`fortran-comment-line-extra-indent'
  Amount of extra indentation for text in full-line comments (default 0).
`fortran-comment-indent-style'
  How to indent the text in full-line comments. Allowed values are:
  nil       don't change the indentation
  fixed     indent to `fortran-comment-line-extra-indent' beyond the
              value of either
                `fortran-minimum-statement-indent-fixed' (fixed format) or
                `fortran-minimum-statement-indent-tab' (TAB format),
              depending on the continuation format in use.
  relative  indent to `fortran-comment-line-extra-indent' beyond the
 	      indentation for a line of code.
  (default 'fixed)
`fortran-comment-indent-char'
  Single-character string to be inserted instead of space for
  full-line comment indentation (default \" \").
`fortran-minimum-statement-indent-fixed'
  Minimum indentation for statements in fixed format mode (default 6).
`fortran-minimum-statement-indent-tab'
  Minimum indentation for statements in TAB format mode (default 9).
`fortran-line-number-indent'
  Maximum indentation for line numbers (default 1).  A line number will
  get less than this much indentation if necessary to avoid reaching
  column 5.
`fortran-check-all-num-for-matching-do'
  Non-nil causes all numbered lines to be treated as possible \"continue\"
  statements (default nil).
`fortran-blink-matching-if'
  Non-nil causes \\[fortran-indent-line] on an ENDIF (or ENDDO) statement
  to blink on the matching IF (or DO [WHILE]).  (default nil)
`fortran-continuation-string'
  Single-character string to be inserted in column 5 of a continuation
  line (default \"$\").
`fortran-comment-region'
  String inserted by \\[fortran-comment-region] at start of each line in
  the region (default \"c$$$\").
`fortran-electric-line-number'
  Non-nil causes line number digits to be moved to the correct column
  as typed (default t).
`fortran-break-before-delimiters'
  Non-nil causes lines to be broken before delimiters (default t).

Turning on Fortran mode calls the value of the variable `fortran-mode-hook'
with no args, if that value is non-nil."
  (interactive)
  (kill-all-local-variables)
  (setq major-mode 'fortran-mode
        mode-name "Fortran"
        local-abbrev-table fortran-mode-abbrev-table)
  (set-syntax-table fortran-mode-syntax-table)
  (use-local-map fortran-mode-map)
  (set (make-local-variable 'indent-line-function) 'fortran-indent-line)
  (set (make-local-variable 'indent-region-function)
       (lambda (start end)
         (let (fortran-blink-matching-if ; avoid blinking delay
               indent-region-function)
           (indent-region start end nil))))
  (set (make-local-variable 'require-final-newline) t)
  ;; The syntax tables don't understand the column-0 comment-markers.
  (set (make-local-variable 'comment-use-syntax) nil)
  (set (make-local-variable 'comment-padding) "$$$")
  (set (make-local-variable 'comment-start) fortran-comment-line-start)
  (set (make-local-variable 'comment-start-skip)
       ;; We can't reuse `fortran-comment-line-start-skip' directly because
       ;; it contains backrefs whereas we need submatch-1 to end at the
       ;; beginning of the comment delimiter.
       ;; (concat "\\(\\)\\(![ \t]*\\|" fortran-comment-line-start-skip "\\)")
       "\\(\\)\\(?:^[CcDd*]\\|!\\)\\(?:\\([^ \t\n]\\)\\2+\\)?[ \t]*")
  (set (make-local-variable 'comment-indent-function) 'fortran-comment-indent)
  (set (make-local-variable 'abbrev-all-caps) t)
  (set (make-local-variable 'normal-auto-fill-function) 'fortran-auto-fill)
  (set (make-local-variable 'indent-tabs-mode) (fortran-analyze-file-format))
  (setq mode-line-process '(indent-tabs-mode fortran-tab-mode-string))
  (set (make-local-variable 'fill-column) 72)
  (set (make-local-variable 'fill-paragraph-function) 'fortran-fill-paragraph)
  (set (make-local-variable 'font-lock-defaults)
       '((fortran-font-lock-keywords
          fortran-font-lock-keywords-1
          fortran-font-lock-keywords-2
          fortran-font-lock-keywords-3)
         nil t ((?/ . "$/") ("_$" . "w"))
         fortran-beginning-of-subprogram))
  (set (make-local-variable 'font-lock-syntactic-keywords)
       fortran-font-lock-syntactic-keywords)
  (set (make-local-variable 'imenu-case-fold-search) t)
  (set (make-local-variable 'imenu-generic-expression)
       fortran-imenu-generic-expression)
  (set (make-local-variable 'imenu-syntax-alist) '(("_$" . "w")))
  (set (make-local-variable 'beginning-of-defun-function)
       #'fortran-beginning-of-subprogram)
  (set (make-local-variable 'end-of-defun-function)
       #'fortran-end-of-subprogram)
  (set (make-local-variable 'add-log-current-defun-function)
       #'fortran-current-defun)
  (set (make-local-variable 'dabbrev-case-fold-search) 'case-fold-search)
  (run-hooks 'fortran-mode-hook))


(defsubst fortran-comment-indent ()
  "Return the indentation appropriate for the current comment line.
This is 0 for a line matching `fortran-comment-line-start-skip', else
the value of `comment-column' (leaving at least one space after code)."
  (if (looking-at fortran-comment-line-start-skip) 0
    (save-excursion
      (skip-chars-backward " \t")
      (max (1+ (current-column)) comment-column))))

(defun fortran-indent-comment ()
  "Align or create comment on current line.
Existing comments of all types are recognized and aligned.
If the line has no comment, a side-by-side comment is inserted and aligned,
if the value of `comment-start' is not nil and allows such comments.
Otherwise, a separate-line comment is inserted, on this line
or on a new line inserted before this line if this line is not blank."
  (interactive "*")
  (beginning-of-line)
  ;; Recognize existing comments of either kind.
  (cond ((fortran-find-comment-start-skip 'all)
	 (goto-char (match-beginning 0))
	 (if (bolp)
	     (fortran-indent-line)
	   (unless (= (current-column) (fortran-comment-indent))
             (delete-horizontal-space)
             (indent-to (fortran-comment-indent)))))
	;; No existing comment.
	;; If side-by-side comments are defined, insert one,
	;; unless line is now blank.
	((and comment-start (not (looking-at "[ \t]*$"))
	      (string-match comment-start-skip (concat " " comment-start)))
	 (end-of-line)
	 (delete-horizontal-space)
	 (indent-to (fortran-comment-indent))
	 (insert comment-start))
	;; Else insert separate-line comment, making a new line if nec.
	(t
	 (if (looking-at "^[ \t]*$")
	     (delete-horizontal-space)
	   (beginning-of-line)
	   (insert ?\n)
	   (forward-char -1))
	 (insert fortran-comment-line-start)
	 (insert-char (if (stringp fortran-comment-indent-char)
			  (aref fortran-comment-indent-char 0)
			fortran-comment-indent-char)
		      (- (fortran-calculate-indent) (current-column))))))

(defun fortran-comment-region (beg-region end-region arg)
  "Comment every line in the region.
Inserts the string variable `fortran-comment-region' at the beginning of
every line in the region.
BEG-REGION and END-REGION specify the region boundaries.
With non-nil ARG, uncomments the region."
  (interactive "*r\nP")
  (let ((end-region-mark (copy-marker end-region))
	(save-point (point-marker)))
    (goto-char beg-region)
    (beginning-of-line)
    (if arg
        (let ((com (regexp-quote fortran-comment-region))) ; uncomment
          (if (looking-at com)
              (delete-region (point) (match-end 0)))
          (while (and (zerop (forward-line 1))
                      (< (point) end-region-mark))
            (if (looking-at com)
                (delete-region (point) (match-end 0)))))
      (insert fortran-comment-region)   ; comment
      (while (and (zerop (forward-line 1))
                  (< (point) end-region-mark))
        (insert fortran-comment-region)))
    (goto-char save-point)
    (set-marker end-region-mark nil)
    (set-marker save-point nil)))


(defun fortran-abbrev-start ()
  "Typing ;\\[help-command] or ;? lists all the Fortran abbrevs.
Any other key combination is executed normally."
  (interactive "*")
  (let (c)
    (insert last-command-char)
    (if (and abbrev-mode
             (or (eq (setq c (read-event)) ??) ; insert char if not `?'
                 (eq c help-char)))
	(fortran-abbrev-help)
      (setq unread-command-events (list c)))))

(defun fortran-abbrev-help ()
  "List the currently defined abbrevs in Fortran mode."
  (interactive)
  (message "Listing abbrev table...")
  (display-buffer (fortran-prepare-abbrev-list-buffer))
  (message "Listing abbrev table...done"))

(defun fortran-prepare-abbrev-list-buffer ()
  "Create a buffer listing the Fortran mode abbreviations."
  (save-excursion
    (set-buffer (get-buffer-create "*Abbrevs*"))
    (erase-buffer)
    (insert-abbrev-table-description 'fortran-mode-abbrev-table t)
    (goto-char (point-min))
    (set-buffer-modified-p nil)
    (edit-abbrevs-mode))
  (get-buffer-create "*Abbrevs*"))

(defun fortran-column-ruler ()
  "Insert a column ruler momentarily above current line, till next keystroke.
The ruler is defined by the value of `fortran-column-ruler-fixed' in fixed
format mode, and `fortran-column-ruler-tab' in TAB format mode.
The next key typed is executed unless it is SPC."
  (interactive)
  (momentary-string-display
   (if indent-tabs-mode
       fortran-column-ruler-tab
     fortran-column-ruler-fixed)
   (save-excursion
     (beginning-of-line)
     (if (eq (window-start (selected-window))
	     (window-point (selected-window)))
	 (line-beginning-position 2)
       (point)))
   nil "Type SPC or any command to erase ruler."))

(defun fortran-window-create ()
  "Make the window 72 columns wide.
See also `fortran-window-create-momentarily'."
  (interactive)
  (let ((window-min-width 2))
    (if (< (window-width) (frame-width))
	(enlarge-window-horizontally (- (frame-width)
					(window-width) 1)))
    (let* ((window-edges (window-edges))
	   (scroll-bar-width (- (nth 2 window-edges)
				(car window-edges)
				(window-width))))
      (split-window-horizontally (+ 72 scroll-bar-width)))
    (other-window 1)
    (switch-to-buffer " fortran-window-extra" t)
    (select-window (previous-window))))

(defun fortran-window-create-momentarily (&optional arg)
  "Momentarily make the window 72 columns wide.
Optional ARG non-nil and non-unity disables the momentary feature.
See also `fortran-window-create'."
  (interactive "p")
  (if (or (not arg)
	  (= arg 1))
      (save-window-excursion
	(progn
	  (condition-case nil
	      (fortran-window-create)
	    (error (error "No room for Fortran window")))
	  (message "Type SPC to continue editing.")
	  (let ((char (read-event)))
	    (or (equal char (string-to-char " "))
		(setq unread-command-events (list char))))))
    (fortran-window-create)))

(defun fortran-split-line ()
  "Break line at point and insert continuation marker and alignment."
  (interactive "*")
  (delete-horizontal-space)
  (if (save-excursion
	(let ((pos (point)))
	  (beginning-of-line)
	  (and (fortran-find-comment-start-skip 'all)
	       (< (match-beginning 0) pos))))
      (insert ?\n (match-string 0))
    (if indent-tabs-mode
	(insert ?\n ?\t (fortran-numerical-continuation-char))
      (insert "\n " fortran-continuation-string))) ; space after \n important
  (fortran-indent-line))               ; when cont string is C, c or *

(defun fortran-remove-continuation ()
  "Delete any Fortran continuation characters at point.
Returns t if anything actually deleted."
  (when (looking-at "\\( \\{5\\}[^ 0\n]\\|\t[1-9]\\|&\\)")
    (replace-match "")
    (delete-indentation)
    t))

(defun fortran-join-line (arg)
  "Join current line to the previous one and re-indent.
With a prefix argument, repeat this operation that many times.
If the prefix argument ARG is negative, join the next -ARG lines.
Continuation lines are correctly handled."
  (interactive "*p")
  (save-excursion
    (when (> 0 arg)
      (setq arg (- arg))
      (forward-line arg))
    (while (not (zerop arg))
      (beginning-of-line)
      (or (fortran-remove-continuation)
          (delete-indentation))
      (setq arg (1- arg)))
    (fortran-indent-line)))

(defun fortran-numerical-continuation-char ()
  "Return a digit for tab-digit style of continuation lines.
If previous line is a tab-digit continuation line, return that digit
plus one, otherwise return 1.  Zero not allowed."
  (save-excursion
    (forward-line -1)
    (if (looking-at "\t[1-9]")
	(+ ?1 (% (- (char-after (1+ (point))) ?0) 9))
      ?1)))

(put 'fortran-electric-line-number 'delete-selection t)
(defun fortran-electric-line-number (arg)
  "Self insert, but if part of a Fortran line number indent it automatically.
Auto-indent does not happen if a numeric ARG is used."
  (interactive "*P")
  (if (or arg (not fortran-electric-line-number))
      (if arg
	  (self-insert-command (prefix-numeric-value arg))
	(self-insert-command 1))
    (if (or (and (= 5 (current-column))
		 (save-excursion
		   (beginning-of-line)
                    ;; In col 5 with only spaces to the left.
		   (looking-at " \\{5\\}")))
	    (and (= (if indent-tabs-mode
			fortran-minimum-statement-indent-tab
		      fortran-minimum-statement-indent-fixed) (current-column))
                 ;; In col 8 with a single tab to the left.
		 (eq ?\t (char-after (line-beginning-position))) 
		 (not (or (eq last-command 'fortran-indent-line)
			  (eq last-command
			      'fortran-indent-new-line))))
	    (save-excursion
	      (re-search-backward "[^ \t0-9]"
				  (line-beginning-position)
				  t))	; not a line number
	    (looking-at "[0-9]"))	; within a line number
	(self-insert-command (prefix-numeric-value arg))
      (skip-chars-backward " \t")
      (insert last-command-char)
      (fortran-indent-line))))


(defun fortran-check-end-prog-re ()
  "Check a preliminary match against `fortran-end-prog-re'."
  ;; Having got a possible match for the subprogram end, we need a
  ;; match of whitespace, avoiding possible column 73+ stuff.
  (save-match-data
    (string-match "^\\s-*\\(\\'\\|\\s<\\)"
		  (buffer-substring (match-end 0)
				    (min (line-end-position)
					 (+ 72 (line-beginning-position)))))))

;; Note that you can't just check backwards for `subroutine' &c in
;; case of un-marked main programs not at the start of the file.
(defun fortran-beginning-of-subprogram ()
  "Move point to the beginning of the current Fortran subprogram."
  (interactive)
  (save-match-data
    (let ((case-fold-search t))
      (beginning-of-line -1)
      (if (catch 'ok
	    (while (re-search-backward fortran-end-prog-re nil 'move)
	      (if (fortran-check-end-prog-re)
		  (throw 'ok t))))
	  (forward-line)))))

(defun fortran-end-of-subprogram ()
  "Move point to the end of the current Fortran subprogram."
  (interactive)
  (save-match-data
    (let ((case-fold-search t))
      (if (save-excursion		; on END
	    (beginning-of-line)
	    (and (looking-at fortran-end-prog-re)
		 (fortran-check-end-prog-re)))
	  (forward-line)
	(beginning-of-line 2)
	(catch 'ok
	  (while (re-search-forward fortran-end-prog-re nil 'move)
	    (if (fortran-check-end-prog-re)
		(throw 'ok t))))
	(goto-char (match-beginning 0))
	(forward-line)))))

(defun fortran-previous-statement ()
  "Move point to beginning of the previous Fortran statement.
Returns 'first-statement if that statement is the first
non-comment Fortran statement in the file, and nil otherwise.
Directive lines are treated as comments."
  (interactive)
  (let (not-first-statement continue-test)
    (beginning-of-line)
    (setq continue-test
	  (and
	   (not (looking-at fortran-comment-line-start-skip))
           (not (looking-at fortran-directive-re))
	   (or (looking-at
	        (concat "[ \t]*"
			(regexp-quote fortran-continuation-string)))
	       (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]"))))
    (while (and (setq not-first-statement (zerop (forward-line -1)))
		(or (looking-at fortran-comment-line-start-skip)
                    (looking-at fortran-directive-re)
                    (looking-at
                     (concat "[ \t]*"
                             (regexp-quote fortran-continuation-string)))
		    (looking-at "[ \t]*$\\| \\{5\\}[^ 0\n]\\|\t[1-9]")
		    (looking-at (concat "[ \t]*" comment-start-skip)))))
    (cond ((and continue-test
		(not not-first-statement))
	   (message "Incomplete continuation statement."))
	  (continue-test
	   (fortran-previous-statement))
	  ((not not-first-statement)
	   'first-statement))))

(defun fortran-next-statement ()
  "Move point to beginning of the next Fortran statement.
Returns 'last-statement if that statement is the last
non-comment Fortran statement in the file, and nil otherwise.
Directive lines are treated as comments."
  (interactive)
  (let (not-last-statement)
    (beginning-of-line)
    (while (and (setq not-last-statement
		      (and (zerop (forward-line 1))
			   (not (eobp))))
 		(or (looking-at fortran-comment-line-start-skip)
                    (looking-at fortran-directive-re)
 		    (looking-at "[ \t]*$\\|     [^ 0\n]\\|\t[1-9]")
 		    (looking-at (concat "[ \t]*" comment-start-skip)))))
    (if (not not-last-statement)
 	'last-statement)))


(defun fortran-blink-match (regex keyword find-begin)
  "From a line matching REGEX, blink matching KEYWORD statement line.
Use function FIND-BEGIN to match it."
  (let ((top-of-window (window-start))
	(end-point (point))
	(case-fold-search t)
	matching
	message)
    (when (save-excursion
            (beginning-of-line)
            (skip-chars-forward " \t0-9")
            (looking-at regex))
      (if (not (setq matching (funcall find-begin)))
          (setq message (concat "No matching " keyword "."))
        (if (< matching top-of-window)
            (save-excursion
              (goto-char matching)
              (beginning-of-line)
              (setq message
                    (concat "Matches "
                            (buffer-substring (point)
                                              (line-end-position)))))))
      (if message
          (message "%s" message)
        (goto-char matching)
        (sit-for 1)
        (goto-char end-point)))))

(defun fortran-blink-matching-if ()
  "From an ENDIF or ELSE statement, blink the matching IF statement."
  (fortran-blink-match "e\\(nd[ \t]*if\\|lse\\([ \t]*if\\)?\\)\\b"
		       "if" #'fortran-beginning-if))

(defun fortran-blink-matching-do ()
  "From an ENDDO statement, blink the matching DO or DO WHILE statement."
  (fortran-blink-match "end[ \t]*do\\b" "do" #'fortran-beginning-do))

(defun fortran-mark-do ()
  "Put mark at end of Fortran DO [WHILE]-ENDDO construct, point at beginning.
The marks are pushed."
  (interactive)
  (let (enddo-point do-point)
    (if (setq enddo-point (fortran-end-do))
        (if (not (setq do-point (fortran-beginning-do)))
            (message "No matching do.")
          (goto-char enddo-point)
          (push-mark)
          (goto-char do-point)))))

(defun fortran-end-do ()
  "Search forward for first unmatched ENDDO.
Return point or nil."
  (let ((case-fold-search t))
    (if (save-excursion (beginning-of-line)
			(skip-chars-forward " \t0-9")
			(looking-at "end[ \t]*do\\b"))
	;; Sitting on one.
	(match-beginning 0)
      ;; Search for one.
      (save-excursion
	(let ((count 1))
	  (while (and (not (zerop count))
		      (not (eq (fortran-next-statement) 'last-statement))
		      ;; Keep local to subprogram.
		      (not (and (looking-at fortran-end-prog-re)
				(fortran-check-end-prog-re))))
	    (skip-chars-forward " \t0-9")
	    (cond ((looking-at "end[ \t]*do\\b")
		   (setq count (1- count)))
		  ((looking-at
		    "\\(\\(\\sw\\|\\s_\\)+:[ \t]*\\)?do[ \t]+[^0-9]")
		   (setq count (1+ count)))))
	  (and (zerop count)
	       ;; All pairs accounted for.
	       (point)))))))

(defun fortran-beginning-do ()
  "Search backwards for first unmatched DO [WHILE].
Return point or nil.  Ignores labelled DO loops (ie DO 10 ... 10 CONTINUE)."
  (let ((case-fold-search t)
        (dostart-re "\\(\\(\\sw\\|\\s_\\)+:[ \t]*\\)?do[ \t]+[^0-9]"))
    (if (save-excursion
	  (beginning-of-line)
	  (skip-chars-forward " \t0-9")
	  (looking-at dostart-re))
	;; Sitting on one.
	(match-beginning 0)
      ;; Search for one.
      (save-excursion
	(let ((count 1))
	  (while (and (not (zerop count))
		      (not (eq (fortran-previous-statement) 'first-statement))
		      ;; Keep local to subprogram.
		      (not (and (looking-at fortran-end-prog-re)
				(fortran-check-end-prog-re))))
	    (skip-chars-forward " \t0-9")
	    (cond ((looking-at dostart-re)
		   (setq count (1- count)))
                  ;; Note labelled loop ends not considered.
		  ((looking-at "end[ \t]*do\\b")
		   (setq count (1+ count)))))
	  (and (zerop count)
	       ;; All pairs accounted for.
	       (point)))))))

(defun fortran-mark-if ()
  "Put mark at end of Fortran IF-ENDIF construct, point at beginning.
The marks are pushed."
  (interactive)
  (let (endif-point if-point)
    (if (setq endif-point (fortran-end-if))
        (if (not (setq if-point (fortran-beginning-if)))
            (message "No matching if.")
          ;; Set mark, move point.
          (goto-char endif-point)
          (push-mark)
          (goto-char if-point)))))

(defun fortran-end-if ()
  "Search forwards for first unmatched ENDIF.
Return point or nil."
  (let ((case-fold-search t))
    (if (save-excursion (beginning-of-line)
			(skip-chars-forward " \t0-9")
			(looking-at "end[ \t]*if\\b"))
	;; Sitting on one.
	(match-beginning 0)
      ;; Search for one.  The point has been already been moved to first
      ;; letter on line but this should not cause troubles.
      (save-excursion
	(let ((count 1))
	  (while (and (not (zerop count))
		      (not (eq (fortran-next-statement) 'last-statement))
		      ;; Keep local to subprogram.
		      (not (and (looking-at fortran-end-prog-re)
				(fortran-check-end-prog-re))))
	    (skip-chars-forward " \t0-9")
	    (cond ((looking-at "end[ \t]*if\\b")
		   (setq count (1- count)))
		  ((looking-at fortran-if-start-re)
		   (save-excursion
		     (if (or
			  (looking-at ".*)[ \t]*then\\b[ \t]*[^ \t(=a-z0-9]")
			  (let (then-test) ; multi-line if-then
			    (while
				(and
				 (zerop (forward-line 1))
				 ;; Search forward for then.
				 (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]")
				 (not
				  (setq then-test
					(looking-at
					 ".*then\\b[ \t]*[^ \t(=a-z0-9]")))))
			    then-test))
			 (setq count (1+ count)))))))
	  (and (zerop count)
	       ;; All pairs accounted for.
	       (point)))))))

(defun fortran-beginning-if ()
  "Search backwards for first unmatched IF-THEN.
Return point or nil."
  (let ((case-fold-search t))
    (if (save-excursion
	  ;; May be sitting on multi-line if-then statement, first
	  ;; move to beginning of current statement.  Note:
	  ;; `fortran-previous-statement' moves to previous statement
	  ;; *unless* current statement is first one.  Only move
	  ;; forward if not first-statement.
	  (if (not (eq (fortran-previous-statement) 'first-statement))
	      (fortran-next-statement))
	  (skip-chars-forward " \t0-9")
	  (and
	   (looking-at fortran-if-start-re)
	   (save-match-data
	     (or (looking-at ".*)[ \t]*then\\b[ \t]*[^ \t(=a-z0-9]")
		 ;; Multi-line if-then.
		 (let (then-test)
		   (while
                       (and (zerop (forward-line 1))
			    ;; Search forward for then.
			    (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]")
			    (not
			     (setq then-test
				   (looking-at
				    ".*then\\b[ \t]*[^ \t(=a-z0-9]")))))
		   then-test)))))
	;; Sitting on one.
	(match-beginning 0)
      ;; Search for one.
      (save-excursion
	(let ((count 1))
	  (while (and (not (zerop count))
		      (not (eq (fortran-previous-statement) 'first-statement))
		      ;; Keep local to subprogram.
		      (not (and (looking-at fortran-end-prog-re)
				(fortran-check-end-prog-re))))
	    (skip-chars-forward " \t0-9")
	    (cond ((looking-at fortran-if-start-re)
		   (save-excursion
		     (if (or
			  (looking-at ".*)[ \t]*then\\b[ \t]*[^ \t(=a-z0-9]")
			  (let (then-test) ; multi-line if-then
			    (while
				(and
				 (zerop (forward-line 1))
				 ;; Search forward for then.
				 (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]")
				 (not
				  (setq then-test
					(looking-at
					 (concat ".*then\\b[ \t]*"
						 "[^ \t(=a-z0-9]"))))))
			    then-test))
			 (setq count (1- count)))))
		  ((looking-at "end[ \t]*if\\b")
		   (setq count (1+ count)))))
	  (and (zerop count)
	       ;; All pairs accounted for.
	       (point)))))))


(defun fortran-indent-line ()
  "Indent current Fortran line based on its contents and on previous lines."
  (interactive "*")
  (let ((cfi (fortran-calculate-indent)))
    (save-excursion
      (beginning-of-line)
      (if (or (not (= cfi (fortran-current-line-indentation)))
	      (and (re-search-forward "^[ \t]*[0-9]+" (+ (point) 4) t)
		   (not (fortran-line-number-indented-correctly-p))))
	  (fortran-indent-to-column cfi)
	(beginning-of-line)
	(if (fortran-find-comment-start-skip)
	    (fortran-indent-comment))))
    ;; Never leave point in left margin.
    (if (< (current-column) cfi)
	(move-to-column cfi))
    (and auto-fill-function
         (> (save-excursion (end-of-line) (current-column))
            fill-column)
         (save-excursion
           (end-of-line)
           (fortran-fill)))
    (when fortran-blink-matching-if
      (fortran-blink-matching-if)
      (fortran-blink-matching-do))))

(defun fortran-auto-fill ()
  "Function to use for `normal-auto-fill-function' in Fortran mode."
  (if (> (current-column) (current-fill-column))
      (let ((cfi (fortran-calculate-indent)))
	(save-excursion
	  (beginning-of-line)
	  (if (or (not (= cfi (fortran-current-line-indentation)))
		  (and (re-search-forward "^[ \t]*[0-9]+"
					  (+ (point) 4) t)
		       (not (fortran-line-number-indented-correctly-p))))
	      (fortran-indent-to-column cfi)
	    (beginning-of-line)
	    (if (fortran-find-comment-start-skip)
		(fortran-indent-comment))))
	(fortran-fill)
	;; Never leave point in left margin.
	(if (< (current-column) cfi)
	    (move-to-column cfi)))))

;; Historically this was a separate function which advertised itself
;; as reindenting but only did so where `most likely to be necessary'.
(defalias 'fortran-indent-new-line 'reindent-then-newline-and-indent)

(defun fortran-indent-subprogram ()
  "Properly indent the Fortran subprogram containing point."
  (interactive "*")
  (save-excursion
    (mark-defun)
    (message "Indenting subprogram...")
    (indent-region (point) (mark) nil))
  (message "Indenting subprogram...done."))

(defun fortran-calculate-indent ()
  "Calculates the Fortran indent column based on previous lines."
  (let (icol first-statement (case-fold-search t)
	     (fortran-minimum-statement-indent
	      (if indent-tabs-mode
		  fortran-minimum-statement-indent-tab
		fortran-minimum-statement-indent-fixed)))
    (save-excursion
      (setq first-statement (fortran-previous-statement))
      (if first-statement
	  (setq icol fortran-minimum-statement-indent)
        (if (= (point) (point-min))
            (setq icol fortran-minimum-statement-indent)
          (setq icol (fortran-current-line-indentation)))
        (skip-chars-forward " \t0-9")
        (cond ((looking-at "\\(\\(\\sw\\|\\s_\\)+:[ \t]*\\)?if[ \t]*(")
               (if (or (looking-at ".*)[ \t]*then\\b[ \t]*[^ \t_$(=a-z0-9]")
                       (let (then-test)	; multi-line if-then
                         (while (and (zerop (forward-line 1))
                                     ;; Search forward for then.
                                     (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]")
                                     (not (setq then-test
                                                (looking-at
                                                 ".*then\\b[ \t]\
*[^ \t_$(=a-z0-9]")))))
                         then-test))
                   (setq icol (+ icol fortran-if-indent))))
              ((looking-at "else\\(if\\)?\\b")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "select[ \t]*case[ \t](.*)")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "case[ \t]*(.*)")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "case[ \t]*default\\b")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "\\(otherwise\\|else[ \t]*where\\)\\b")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "where[ \t]*(.*)[ \t]*\n")
               (setq icol (+ icol fortran-if-indent)))
              ((looking-at "do\\b")
               (setq icol (+ icol fortran-do-indent)))
              ((looking-at
                "\\(structure\\|union\\|map\\|interface\\)\
\\b[ \t]*[^ \t=(a-z]")
               (setq icol (+ icol fortran-structure-indent)))
              ((and (looking-at fortran-end-prog-re1)
                    (fortran-check-end-prog-re))
               ;; Previous END resets indent to minimum.
               (setq icol fortran-minimum-statement-indent)))))
    (save-excursion
      (beginning-of-line)
      (cond ((looking-at "[ \t]*$"))
            ;; Check for directive before comment, so as not to indent.
	    ((looking-at fortran-directive-re)
	     (setq fortran-minimum-statement-indent 0 icol 0))
	    ((looking-at fortran-comment-line-start-skip)
	     (cond ((eq fortran-comment-indent-style 'relative)
		    (setq icol (+ icol fortran-comment-line-extra-indent)))
		   ((eq fortran-comment-indent-style 'fixed)
		    (setq icol (+ fortran-minimum-statement-indent
				  fortran-comment-line-extra-indent))))
	     (setq fortran-minimum-statement-indent 0))
     	    ((or (looking-at (concat "[ \t]*"
				     (regexp-quote
				      fortran-continuation-string)))
		 (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]"))
             (skip-chars-forward " \t")
             ;; Do not introduce extra whitespace into a broken string.
             (setq icol
                   (if (fortran-is-in-string-p (point))
                       6
                     (+ icol fortran-continuation-indent))))
	    (first-statement)
	    ((and fortran-check-all-num-for-matching-do
		  (looking-at "[ \t]*[0-9]+")
		  (fortran-check-for-matching-do))
	     (setq icol (- icol fortran-do-indent)))
	    (t
	     (skip-chars-forward " \t0-9")
	     (cond ((looking-at "end[ \t]*\\(if\\|select\\|where\\)\\b")
		    (setq icol (- icol fortran-if-indent)))
		   ((looking-at "else\\(if\\)?\\b")
		    (setq icol (- icol fortran-if-indent)))
                   ((looking-at "case[ \t]*\\((.*)\\|default\\>\\)")
		    (setq icol (- icol fortran-if-indent)))
		   ((looking-at "\\(otherwise\\|else[ \t]*where\\)\\b")
		    (setq icol (- icol fortran-if-indent)))
		   ((and (looking-at "continue\\b")
			 (fortran-check-for-matching-do))
		    (setq icol (- icol fortran-do-indent)))
		   ((looking-at "end[ \t]*do\\b")
		    (setq icol (- icol fortran-do-indent)))
		   ((looking-at "end[ \t]*\
\\(structure\\|union\\|map\\|interface\\)\\b[ \t]*[^ \t=(a-z]")
		    (setq icol (- icol fortran-structure-indent)))
		   ((and (looking-at fortran-end-prog-re1)
			 (fortran-check-end-prog-re)
			 (not (= icol fortran-minimum-statement-indent)))
 		    (message "Warning: `end' not in column %d.  Probably\
 an unclosed block." fortran-minimum-statement-indent))))))
    (max fortran-minimum-statement-indent icol)))


(defun fortran-current-line-indentation ()
  "Indentation of current line, ignoring Fortran line number or continuation.
This is the column position of the first non-whitespace character
aside from the line number and/or column 5/8 line-continuation character.
For comment lines, returns indentation of the first
non-indentation text within the comment."
  (save-excursion
    (beginning-of-line)
    (cond ((looking-at fortran-comment-line-start-skip)
	   (goto-char (match-end 0))
	   (skip-chars-forward
	    (if (stringp fortran-comment-indent-char)
		fortran-comment-indent-char
	      (char-to-string fortran-comment-indent-char))))
	  ((or (looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]"))
	   (goto-char (match-end 0)))
	  (t
	   ;; Move past line number.
	   (skip-chars-forward "[ \t0-9]")))
    ;; Move past whitespace.
    (skip-chars-forward " \t")
    (current-column)))

(defun fortran-indent-to-column (col)
  "Indent current line to column COL.
notes: 1) A non-zero/non-blank character in column 5 indicates a continuation
          line, and this continuation character is retained on indentation;
       2) If `fortran-continuation-string' is the first non-whitespace
          character, this is a continuation line;
       3) A non-continuation line which has a number as the first
          non-whitespace character is a numbered line.
       4) A TAB followed by a digit indicates a continuation line."
  (save-excursion
    (beginning-of-line)
    (if (looking-at fortran-comment-line-start-skip)
	(if fortran-comment-indent-style
	    (let* ((char (if (stringp fortran-comment-indent-char)
			     (aref fortran-comment-indent-char 0)
			   fortran-comment-indent-char))
		   (chars (string ?  ?\t char)))
	      (goto-char (match-end 0))
	      (skip-chars-backward chars)
	      (delete-region (point) (progn (skip-chars-forward chars)
					    (point)))
	      (insert-char char (- col (current-column)))))
      (if (looking-at "\t[1-9]")
	  (if indent-tabs-mode
	      (goto-char (match-end 0))
	    (delete-char 2)
	    (insert-char ?  5)
	    (insert fortran-continuation-string))
	(if (looking-at " \\{5\\}[^ 0\n]")
	    (if indent-tabs-mode
		(progn (delete-char 6)
		       (insert ?\t (fortran-numerical-continuation-char) 1))
	      (forward-char 6))
	  (delete-horizontal-space)
	  ;; Put line number in columns 0-4, or
          ;; continuation character in column 5.
	  (cond ((eobp))
		((looking-at (regexp-quote fortran-continuation-string))
		 (if indent-tabs-mode
		     (progn
		       (indent-to
			(if indent-tabs-mode
			    fortran-minimum-statement-indent-tab
			  fortran-minimum-statement-indent-fixed))
		       (delete-char 1)
		       (insert-char (fortran-numerical-continuation-char) 1))
		   (indent-to 5)
		   (forward-char 1)))
		((looking-at "[0-9]+")
		 (let ((extra-space (- 5 (- (match-end 0) (point)))))
		   (if (< extra-space 0)
		       (message "Warning: line number exceeds 5-digit limit.")
		     (indent-to (min fortran-line-number-indent extra-space))))
		 (skip-chars-forward "0-9")))))
      ;; Point is now after any continuation character or line number.
      ;; Put body of statement where specified.
      (delete-horizontal-space)
      (indent-to col)
      ;; Indent any comment following code on the same line.
      (when (fortran-find-comment-start-skip)
        (goto-char (match-beginning 0))
        (unless (= (current-column) (fortran-comment-indent))
          (delete-horizontal-space)
          (indent-to (fortran-comment-indent)))))))

(defun fortran-line-number-indented-correctly-p ()
  "Return t if current line's line number is correctly indented.
Do not call if there is no line number."
  (save-excursion
    (beginning-of-line)
    (skip-chars-forward " \t")
    (and (<= (current-column) fortran-line-number-indent)
	 (or (= (current-column) fortran-line-number-indent)
	     (progn (skip-chars-forward "0-9")
		    (= (current-column) 5))))))

(defun fortran-check-for-matching-do ()
  "When called from a numbered statement, return t if matching DO is found.
Otherwise return nil."
  (let ((case-fold-search t)
	charnum)
    (save-excursion
      (beginning-of-line)
      (when (looking-at "[ \t]*[0-9]+")
        (skip-chars-forward " \t")
        (skip-chars-forward "0")	; skip past leading zeros
        (setq charnum
              (buffer-substring (point) (progn
                                          (skip-chars-forward "0-9")
                                          (point))))
        (beginning-of-line)
        (save-restriction
          (save-excursion
            (narrow-to-defun)
            (and (re-search-backward
                  (concat
                   "\\(^[ \t0-9]*do[ \t]*0*"
                   charnum "\\b\\)\\|" "\\(^[ \t]*0*"
                   charnum "\\b\\)")
                  nil t)
                 (looking-at
                  (concat "^[ \t0-9]*do[ \t]*0*"
                          charnum)))))))))

(defun fortran-find-comment-start-skip (&optional all)
  "Move to past `comment-start-skip' found on current line.
Return non-nil if `comment-start-skip' found, nil if not.
If ALL is nil, only match comments that start in column > 0."
  ;; Hopefully at some point we can just use the line below!  -stef
  ;; (comment-search-forward (line-end-position) t))
  (when (or all comment-start-skip)
    (let ((pos (point))
	  (css (if comment-start-skip
		   (concat fortran-comment-line-start-skip
			   "\\|" comment-start-skip)
		 fortran-comment-line-start-skip)))
      (when (re-search-forward css (line-end-position) t)
	(if (and (or all (> (match-beginning 0) (line-beginning-position)))
		 (or (save-match-data
		       (not (fortran-is-in-string-p (match-beginning 0))))
		     ;; Recurse for rest of line.
		     (fortran-find-comment-start-skip all)))
	    (point)
	  (goto-char pos)
	  nil)))))

;; From: ralf@up3aud1.gwdg.de (Ralf Fassel)
;; Test if TAB format continuation lines work.
(defun fortran-is-in-string-p (where)
  "Return non-nil iff WHERE (a buffer position) is inside a Fortran string."
  (save-excursion
    (goto-char where)
    (cond
     ((bolp) nil)			; bol is never inside a string
     ((save-excursion			; comment lines too
	(beginning-of-line)
	(looking-at fortran-comment-line-start-skip)) nil)
     (t (let ((parse-state '(0 nil nil nil nil nil 0))
	      (quoted-comment-start (if comment-start
					(regexp-quote comment-start)))
	      (not-done t)
	      parse-limit end-of-line)
	  ;; Move to start of current statement.
	  (fortran-next-statement)
	  (fortran-previous-statement)
	  ;; Now parse up to WHERE.
	  (while not-done
	    (if (or ;; Skip to next line if:
		 ;; - comment line?
		 (looking-at fortran-comment-line-start-skip)
		 ;; - at end of line?
		 (eolp)
		 ;; - not in a string and after comment-start?
		 (and (not (nth 3 parse-state))
		      comment-start
		      (equal comment-start
			     (char-to-string (preceding-char)))))
		(if (> (forward-line) 0)
		    (setq not-done nil))
	      ;; else:
	      ;; If we are at beginning of code line, skip any
	      ;; whitespace, labels and tab continuation markers.
	      (if (bolp) (skip-chars-forward " \t0-9"))
	      ;; If we are in column <= 5 now, check for continuation char.
	      (cond ((= 5 (current-column)) (forward-char 1))
		    ((and (< (current-column) 5)
			  (equal fortran-continuation-string
				 (char-to-string (following-char)))
			  (forward-char 1))))
	      ;; Find out parse-limit from here.
	      (setq end-of-line (line-end-position))
	      (setq parse-limit (min where end-of-line))
	      ;; Parse max up to comment-start, if non-nil and in current line.
	      (if comment-start
		  (save-excursion
		    (if (re-search-forward quoted-comment-start end-of-line t)
			(setq parse-limit (min (point) parse-limit)))))
	      ;; Now parse if still in limits.
	      (if (< (point) where)
		  (setq parse-state (parse-partial-sexp
				     (point) parse-limit nil nil parse-state))
		(setq not-done nil))))
	  ;; Result.
	  (nth 3 parse-state))))))

;; From old version.
(defalias 'fortran-auto-fill-mode 'auto-fill-mode)

(defun fortran-fill ()
  "Fill the current line at an appropriate point(s)."
  (let* ((auto-fill-function #'fortran-auto-fill)
	 (opoint (point))
	 (bol (line-beginning-position))
	 (eol (line-end-position))
	 (bos (min eol (+ bol (fortran-current-line-indentation))))
	 (quote
	  (save-excursion
	    (goto-char bol)
	    ;; OK to break quotes on comment lines.
	    (unless (looking-at fortran-comment-line-start-skip)
              (let (fcpoint start)
	      (move-to-column fill-column)
	      (when (fortran-is-in-string-p (setq fcpoint (point)))
                (save-excursion
                  (re-search-backward "\\S\"\\s\"\\S\"" bol t)
                  (setq start
                        (if fortran-break-before-delimiters
                            (point)
                          (1+ (point)))))
                (if (re-search-forward "\\S\"\\s\"\\S\"" eol t)
                    (backward-char 2))
                ;; If the current string is longer than 72 - 6 chars,
                ;; break it at the fill column (else infinite loop).
                (if (> (- (point) start)
                       (- fill-column 6 fortran-continuation-indent))
                    fcpoint
                  start))))))
	 ;; Decide where to split the line. If a position for a quoted
	 ;; string was found above then use that, else break the line
	 ;; before the last delimiter.
	 ;; Delimiters are whitespace, commas, and operators.
	 ;; Will break before a pair of *'s.
	 (fill-point
	  (or quote
	      (save-excursion
		(move-to-column (1+ fill-column))
                ;; GM Make this a defcustom as in f90-mode? Add ", (?
		(skip-chars-backward "^ \t\n,'+-/*=)"
;;;		 (if fortran-break-before-delimiters
;;;		     "^ \t\n,'+-/*=" "^ \t\n,'+-/*=)")
		 )
		(when (<= (point) (1+ bos))
                  (move-to-column (1+ fill-column))
                  ;; What is this doing???
                  (or (re-search-forward "[\t\n,'+-/*)=]" eol t)
                      (goto-char bol)))
		(if (bolp)
		    (re-search-forward "[ \t]" opoint t)
		  (backward-char)
		  (if (looking-at "\\s\"")
		      (forward-char)
		    (skip-chars-backward " \t\*")))
		(if fortran-break-before-delimiters
		    (point)
		  (1+ (point)))))))
    ;; If we are in an in-line comment, don't break unless the
    ;; line of code is longer than it should be. Otherwise
    ;; break the line at the column computed above.
    ;;
    ;; Need to use fortran-find-comment-start-skip to make sure that
    ;; quoted !'s don't prevent a break.
    (when (and (save-excursion
		 (beginning-of-line)
		 (if (not (fortran-find-comment-start-skip))
                     t
		   (goto-char (match-beginning 0))
		   (>= (point) fill-point)))
	       (save-excursion
		 (goto-char fill-point)
		 (not (bolp)))
	       (> (save-excursion
		    (goto-char opoint)
		    (current-column))
		  (min (1+ fill-column)
		       (+ (fortran-calculate-indent)
			  fortran-continuation-indent))))
      (goto-char fill-point)
      (fortran-break-line)
      (end-of-line))))

(defun fortran-break-line ()
  "Call `fortran-split-line'.  Joins continuation lines first, then refills."
  (let ((opoint (point))
	(bol (line-beginning-position))
	(comment-string
	 (save-excursion
	   (if (fortran-find-comment-start-skip)
	       (delete-and-extract-region
		(match-beginning 0) (line-end-position))))))
    ;; Forward line 1 really needs to go to next non white line.
    (if (save-excursion (forward-line)
			(looking-at " \\{5\\}[^ 0\n]\\|\t[1-9]"))
	(progn
	  (end-of-line)
	  (delete-region (point) (match-end 0))
	  (delete-horizontal-space)
	  (fortran-fill))
      (fortran-split-line))
    (if comment-string
	(save-excursion
	  (goto-char bol)
	  (end-of-line)
	  (delete-horizontal-space)
	  (indent-to (fortran-comment-indent))
	  (insert comment-string)))))

(defun fortran-analyze-file-format ()
  "Return nil if fixed format is used, t if TAB formatting is used.
Use `fortran-tab-mode-default' if no non-comment statements are found
before the end or in the first `fortran-analyze-depth' lines."
  (let ((i 0))
    (save-excursion
      (goto-char (point-min))
      (while (not (or
		   (eobp)
		   (eq (char-after) ?\t)
		   (looking-at " \\{6\\}")
		   (> i fortran-analyze-depth)))
	(forward-line)
	(setq i (1+ i)))
      (cond
       ((eq (char-after) ?\t) t)
       ((looking-at " \\{6\\}") nil)
       (t fortran-tab-mode-default)))))

(defun fortran-fill-paragraph (&optional justify)
  "Fill surrounding comment block as paragraphs, else fill statement.
Intended as the value of `fill-paragraph-function'.
A comment block is filled by calling `fill-comment-paragraph' with
argument JUSTIFY, otherwise `fortran-fill-statement' is called.
Always returns non-nil (to prevent `fill-paragraph' being called)."
  (interactive "*P")
  (or (fill-comment-paragraph justify)
      (fortran-fill-statement)
      t))

(defun fortran-fill-statement ()
  "Fill a Fortran statement up to `fill-column'."
  (interactive "*")
  (let ((auto-fill-function #'fortran-auto-fill))
    (unless (save-excursion
              (beginning-of-line)
              (or (looking-at "[ \t]*$")
                  (looking-at fortran-comment-line-start-skip)
                  (and comment-start-skip
                       (looking-at (concat "[ \t]*" comment-start-skip)))))
      (save-excursion
        ;; Find beginning of statement.
        (fortran-next-statement)
        (fortran-previous-statement)
        ;; Re-indent initially.
        (fortran-indent-line)
        ;; Replace newline plus continuation field plus indentation with
        ;; single space.
        (while (progn
                 (forward-line)
                 (fortran-remove-continuation)))
        (fortran-previous-statement)))
    (fortran-indent-line)))

(defun fortran-strip-sequence-nos (&optional do-space)
  "Delete all text in column 72 and up (assumed to be sequence numbers).
Normally also deletes trailing whitespace after stripping such text.
Supplying prefix arg DO-SPACE prevents stripping the whitespace."
  (interactive "*p")
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward "^.\\{72\\}\\(.*\\)" nil t)
      (replace-match "" nil nil nil 1)
      (unless do-space (delete-horizontal-space)))))

;; This code used to live in add-log.el, but this is a better place
;; for it.
(defun fortran-current-defun ()
  "Function to use for `add-log-current-defun-function' in Fortran mode."
  (save-excursion
    ;; We must be inside function body for this to work.
    (fortran-beginning-of-subprogram)
    (let ((case-fold-search t))		; case-insensitive
      ;; Search for fortran subprogram start.
      (if (re-search-forward
           (concat "^[ \t]*\\(program\\|subroutine\\|function"
                   "\\|[ \ta-z0-9*()]*[ \t]+function\\|"
                   "\\(block[ \t]*data\\)\\)")
           (save-excursion (fortran-end-of-subprogram)
                           (point))
           t)
          (or (match-string-no-properties 2)
              (progn
                ;; Move to EOL or before first left paren.
                (if (re-search-forward "[(\n]" nil t)
                    (progn (backward-char)
                           (skip-chars-backward " \t"))
                  (end-of-line))
                ;; Use the name preceding that.
                (buffer-substring-no-properties (point) (progn (backward-sexp)
                                                               (point)))))
        "main"))))

(provide 'fortran)

;;; fortran.el ends here