;;; semantic/doc.el --- Routines for documentation strings

;; Copyright (C) 1999-2003, 2005, 2008-2020 Free Software Foundation,
;; Inc.

;; Author: Eric M. Ludlam <zappo@gnu.org>
;; Keywords: syntax

;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:
;;
;; It is good practice to write documentation for your functions and
;; variables.  These core routines deal with these documentation
;; comments or strings.  They can exist either as a tag property
;; (:documentation) or as a comment just before the symbol, or after
;; the symbol on the same line.

(require 'semantic/tag)

;;; Code:

;;;###autoload
(define-overloadable-function semantic-documentation-for-tag (&optional tag nosnarf)
  "Find documentation from TAG and return it as a clean string.
TAG might have DOCUMENTATION set in it already.  If not, there may be
some documentation in a comment preceding TAG's definition which we
can look for.  When appropriate, this can be overridden by a language specific
enhancement.
Optional argument NOSNARF means to only return the lexical analyzer token for it.
If NOSNARF is `lex', then only return the lex token."
  (if (not tag) (setq tag (semantic-current-tag)))
  (save-excursion
    (when (semantic-tag-with-position-p tag)
      (set-buffer (semantic-tag-buffer tag)))
    (:override
     ;; No override.  Try something simple to find documentation nearby
     (save-excursion
       (semantic-go-to-tag tag)
       (let ((doctmp (semantic-tag-docstring tag (current-buffer))))
	 (or
	  ;; Is there doc in the tag???
	  doctmp
	  ;; Check just before the definition.
	  (when (semantic-tag-with-position-p tag)
	    (semantic-documentation-comment-preceding-tag tag nosnarf))
	  ;;  Let's look for comments either after the definition, but before code:
	  ;; Not sure yet.  Fill in something clever later....
	  nil))))))

(defun semantic-documentation-comment-preceding-tag (&optional tag nosnarf)
  "Find a comment preceding TAG.
If TAG is nil.  use the tag under point.
Searches the space between TAG and the preceding tag for a comment,
and converts the comment into clean documentation.
Optional argument NOSNARF with a value of `lex' means to return
just the lexical token and not the string."
  (if (not tag) (setq tag (semantic-current-tag)))
  (save-excursion
    ;; Find this tag.
    (semantic-go-to-tag tag)
    (let* ((starttag (semantic-find-tag-by-overlay-prev
		      (semantic-tag-start tag)))
	   (start (if starttag
		      (semantic-tag-end starttag)
		    (point-min))))
      (when (and comment-start-skip
		 (re-search-backward comment-start-skip start t))
	;; We found a comment that doesn't belong to the body
	;; of a function.
	(semantic-doc-snarf-comment-for-tag nosnarf)))
    ))
(define-obsolete-function-alias
  'semantic-documentation-comment-preceeding-tag
  'semantic-documentation-comment-preceding-tag
  "25.1")

(defun semantic-doc-snarf-comment-for-tag (nosnarf)
  "Snarf up the comment at POINT for `semantic-documentation-for-tag'.
Attempt to strip out comment syntactic sugar.
Argument NOSNARF means don't modify the found text.
If NOSNARF is `lex', then return the lex token."
  (let* ((semantic-ignore-comments nil)
	 (semantic-lex-analyzer #'semantic-comment-lexer))
    (if (memq nosnarf '(lex flex)) ;; keep `flex' for compatibility
	(car (semantic-lex (point) (1+ (point))))
      (let ((ct (semantic-lex-token-text
		 (car (semantic-lex (point) (1+ (point)))))))
	(if nosnarf
	    nil
	  ;; ok, try to clean the text up.
	  ;; Comment start thingy
	  (while (string-match (concat "^\\s-*\\(?:" comment-start-skip "\\)")
                               ct)
	    (setq ct (concat (substring ct 0 (match-beginning 0))
			     (substring ct (match-end 0)))))
	  ;; Arbitrary punctuation at the beginning of each line.
	  (while (string-match "^\\s-*\\s.+\\s-*" ct)
	    (setq ct (concat (substring ct 0 (match-beginning 0))
			     (substring ct (match-end 0)))))
	  ;; End of a block comment.
	  (if (and (boundp 'block-comment-end)
		   block-comment-end
		   (string-match block-comment-end ct))
	      (setq ct (concat (substring ct 0 (match-beginning 0))
			       (substring ct (match-end 0)))))
	  ;; In case it's a real string, STRIPIT.
	  (while (string-match "\\s-*\\s\"+\\s-*" ct)
	    (setq ct (concat (substring ct 0 (match-beginning 0))
			     (substring ct (match-end 0)))))
	  ;; Remove comment delimiter at the end of the string.
	  (when (and comment-end (not (string= comment-end ""))
		     (string-match (concat (regexp-quote comment-end) "$") ct))
	    (setq ct (substring ct 0 (match-beginning 0)))))
	;; Now return the text.
	ct))))

(provide 'semantic/doc)

;; Local variables:
;; generated-autoload-file: "loaddefs.el"
;; generated-autoload-load-name: "semantic/doc"
;; End:

;;; semantic/doc.el ends here
