Function: c-parse-state-get-strategy

c-parse-state-get-strategy is a byte-compiled function defined in cc-engine.el.gz.

Signature

(c-parse-state-get-strategy HERE GOOD-POS)

Source Code

;; Defined in /usr/src/emacs/lisp/progmodes/cc-engine.el.gz
(defun c-parse-state-get-strategy (here good-pos)
  ;; Determine the scanning strategy for adjusting `c-parse-state', attempting
  ;; to minimize the amount of scanning.  HERE is the pertinent position in
  ;; the buffer, GOOD-POS is a position where `c-state-cache' (possibly with
  ;; its head trimmed) is known to be good, or nil if there is no such
  ;; position.
  ;;
  ;; The return value is a list, one of the following:
  ;;
  ;; o - ('forward START-POINT) - scan forward from START-POINT,
  ;;	 which is not less than the highest position in `c-state-cache' below HERE,
  ;;     which is after GOOD-POS.
  ;; o - ('backward nil) - scan backwards (from HERE).
  ;; o - ('back-and-forward START-POINT) - like 'forward, but when HERE is earlier
  ;;     than GOOD-POS.
  ;; o - ('BOD START-POINT) - scan forwards from START-POINT, which is at the
  ;;   top level.
  ;; o - ('IN-LIT nil) - point is inside the literal containing point-min.
  (let* ((in-macro-start	      ; start of macro containing HERE or nil.
	  (save-excursion
	    (goto-char here)
	    (and (c-beginning-of-macro)
		 (point))))
	 (changed-macro-start
	  (and in-macro-start
	       (not (and c-state-old-cpp-beg
			 (= in-macro-start c-state-old-cpp-beg)))
	       in-macro-start))
	 (cache-pos (c-get-cache-scan-pos (if changed-macro-start
					      (min changed-macro-start here)
					    here))) ; highest suitable position in cache (or 1)
	 BOD-pos		      ; position of 2nd BOD before HERE.
	 strategy		      ; 'forward, 'backward, 'BOD, or 'IN-LIT.
	 start-point
	 how-far)			; putative scanning distance.
    (setq good-pos (or good-pos (c-state-get-min-scan-pos)))
    (cond
     ((< here (c-state-get-min-scan-pos))
      (setq strategy 'IN-LIT
	    start-point nil
	    cache-pos nil
	    how-far 0))
     ((<= good-pos here)
      (setq strategy 'forward
	    start-point (max good-pos cache-pos)
	    how-far (- here start-point)))
     ((< (- good-pos here) (- here cache-pos)) ; FIXME!!! ; apply some sort of weighting.
      (setq strategy 'backward
	    how-far (- good-pos here)))
     (t
      (setq strategy 'back-and-forward
	    start-point cache-pos
	    how-far (- here start-point))))

    ;; Might we be better off starting from the top level, two defuns back,
    ;; instead?  This heuristic no longer works well in C++, where
    ;; declarations inside namespace brace blocks are frequently placed at
    ;; column zero.  (2015-11-10): Remove the condition on C++ Mode.
    (when (and (or (not (memq 'col-0-paren c-emacs-features))
		   open-paren-in-column-0-is-defun-start)
	       ;; (not (c-major-mode-is 'c++-mode))
	       (> how-far c-state-cache-too-far))
      (setq BOD-pos (c-get-fallback-scan-pos here)) ; somewhat EXPENSIVE!!!
      (if (and BOD-pos
	       (< (- here BOD-pos) how-far))
	  (setq strategy 'BOD
		start-point BOD-pos)))

    (list strategy start-point)))