;; The definition of Breccia mode, a major mode for editing Breccian text. -*- lexical-binding: t; -*- ;; ;; USAGE ;; ───── ;; 1. Put a copy of this file on your load path. ;; https://www.gnu.org/software/emacs/manual/html_node/elisp/Library-Search.html ;; ;; 2. Add the following to your initialization file. ;; ;; (autoload 'breccia-mode "breccia-mode" nil t) ;; (set 'auto-mode-alist (cons (cons "\\.brec\\'" 'breccia-mode) auto-mode-alist)) ;; ;; Working example: ;; ;; http://reluk.ca/.emacs.d/lisp/initialization.el ;; http://reluk.ca/.Xresources ;; http://reluk.ca/project/Breccia/Emacs/screen_shot.png ;; ;; ;; CUSTOMIZATION ;; ───────────── ;; For the customizeable faces, see the `defface` declarations further below. ;; ;; If you are coding a derived mode, then see also `brec-command-matcher-components`. ;; ;; ;; TERMS ;; ───── ;; fontification segment ;; One of a document head, point head or divider segment. ;; ;; ;; NOTES (see at bottom) ;; ───── (eval-when-compile (require 'cl-lib)) ;; ══════════════════════════════════════════════════════════════════════════════════════════════════════ ;; P r e l i m i n a r y d e c l a r a t i o n s ;; ══════════════════════════════════════════════════════════════════════════════════════════════════════ (defconst brec-backquoted-pattern-pattern "`\\(?:\\\\.\\|[^\\`]\\)+`" ;; ╵ └────┘ └────┘ ╵ ;; Q BC NQ Q ;; ;; Each element between the backquotes (Q) is either a blackslashed character pair (BC) such as “\n” ;; or “\`”, or a single character that is neither a backslash, nor a backquote (NQ). ;; See also `https://stackoverflow.com/q/249791/2402790`. "\ The regexp pattern of a regexp pattern which is delimited by backquotes.") (defconst brec-gap-pattern "[ \n]+" "The regexp pattern of a gap in a descriptor.") ;;; This is incomplete, it omits commentary and indentation blinds [D]. (defconst brec-seg-start-pattern ; Perfect indentation (PI), [SPC] "^ \\{4\\}*\\\\*[^[:space:]\\]"; zero or more backslashes (\⋯) ;; ┈──────┘└───┘└────────────┘ ; and a character (C) that is neither ;; PI \⋯ C ; whitespace nor a backslash. "\ The regexp pattern of the sequence marking the start of a fontification segment other than a document head.") (defvar font-lock-beg); [FV] (defvar font-lock-end) ;; ══════════════════════════════════════════════════════════════════════════════════════════════════════ ;; D e c l a r a t i o n s i n l e x i c o g r a p h i c o r d e r ;; ══════════════════════════════════════════════════════════════════════════════════════════════════════ (defface brec-alarm-bullet `((t . (:inherit (brec-bullet font-lock-warning-face)))) "\ The face for the bullet of an alarm point." :group 'breccia) (defface brec-alarm-bullet-punctuation `((t . (:inherit brec-alarm-bullet :weight normal))) "\ The face for any non-alphanumeric character of an alarm bullet other than those of ‘brec-alarm-bullet-singleton’ and ‘brec-alarm-bullet-terminator’." :group 'breccia) (defface brec-alarm-bullet-singleton `((t . (:inherit brec-alarm-bullet))) "\ The face for an alarm bullet that comprises ‘!!’ alone." :group 'breccia) (defface brec-alarm-bullet-terminator `((t . (:inherit brec-alarm-bullet-punctuation))) "\ The face for the bullet terminator ‘!!’ of an alarm point. Cf. ‘brec-alarm-bullet-singleton’." :group 'breccia) (defface brec-aside-bullet `((t . (:inherit (brec-bullet brec-aside-descriptor)))) "\ The face for the bullet of an aside point." :group 'breccia) (defface brec-aside-descriptor `((t . (:inherit shadow))) "\ The face for the descriptor of an aside point." :group 'breccia) (defun brec-backward-paragraph () "A Breccian variant of the ‘backward-paragraph’ command. Moves backward to the previous paragraph, as defined by ‘brec-interparagraph-line-offset’." (interactive "^") (brec-move-by-lines (brec-interparagraph-line-offset -1) t "previous line")) (defface brec-bullet `((t . (:inherit bold))) "\ The face for a bullet." :group 'breccia) (defgroup breccia nil "\ A major mode for editing Breccian text" :group 'text :group 'faces :prefix "brec-" :link '(url-link "http://reluk.ca/project/Breccia/Emacs/")) (defface brec-command-keyword `((t . (:inherit brec-command-descriptor))) "\ The face for a keyword in the descriptor of a command point." :group 'breccia) (defface brec-command-bullet `((t . (:inherit (brec-bullet brec-command-descriptor)))) "\ The face for the bullet of a command point." :group 'breccia) (defface brec-command-descriptor `((t . (:inherit font-lock-builtin-face))) "\ The face for the descriptor of a command point." :group 'breccia) (defvar brec-command-matcher-components (let ((bq-pat brec-backquoted-pattern-pattern) (gap brec-gap-pattern)); Lack of commentary or indentation blinds in `brec-gap-pattern` (q.v.) ;;; may cause the highlighter to fail in some texts, leaving a command unhighlighted. [BUG] ;;; An obvious workaround for a user editing the text is to pull commentary and indentation ;;; blinds out of the command and put them instead at the end of the descriptor. (list (concat ":" gap "\\(?:"); (initial component) ;; Associative reference ;; ───────────────────── (concat "\\(?:\\(?1:re\\)" gap bq-pat gap "\\)?"; Referrer clause. ;; Referent clause. It determines the specific type of associative reference as either "\\(?2:join" ; a jointer or "\\|see\\)\\>"; a pointer. "\\(?3:" gap "privately\\>\\)?"); Addtionally it may mark the reference as a private fractum. ;; Privatizer ;; ────────── "\\|\\(?1:private\\)\\>" ;; Other commands ;; ────────────── ;; Components to match new commands may be inserted here. Each must open with "\\|" and may capture ;; up to three, explicitly numbered groups, e.g. `\(?1:first\)`, `\(?2:second\)` and `\(?3:third\)`. ;; The same fontification will be given to each group. For an example of component insertion, ;; see `http://reluk.ca/project/wayic/Waybrec/Emacs/waybrec-mode.el`. "\\)")); (final component) "\ The list of string components that function ‘brec-keywords’ will concatenate in order to form the anchored matcher it uses to fontify the referential-command portion of each command point. Derived modes may modify the list before calling ‘brec-keywords’, e.g. by inserting components in order to fontify additional commands. Developers should read the instructions in the source code of this variable before attempting to do that.") (defface brec-comment-block-label `((t . (:inherit font-lock-doc-face))) "\ The face for a comment block label." :group 'breccia) (defface brec-divider `((t . (:inherit font-lock-doc-face))) "\ The face for a divider." :group 'breccia) (defface brec-division-inverse-labeling `((t . (:inherit (bold brec-divider) :inverse-video t))) "\ The face for inverse labeling and reverse video in a division label." :group 'breccia) (defface brec-division-label `((t . (:inherit brec-divider))) "\ The face for a label in a divider." :group 'breccia) (defface brec-division-titling `((t . (:inherit (bold brec-division-label)))) "\ The face for a titling sequence in a division label." :group 'breccia) (defun brec-extend-search () "Ensures that the font-lock search region extends to cover the whole of its fontification segments, bisecting none of them. Returns nil if already it does, non-nil otherwise." (save-excursion (let ((is-changed (brec-extend-search-up))) (or (brec-extend-search-down) is-changed)))) (defun brec-extend-search-down () "Ensures that ‘font-lock-end’ bisects no fontification segment, moving it forward in the buffer as necessary. Returns nil if no change was required, non-nil otherwise." (goto-char font-lock-end) (unless (or (bolp)(eolp)); When the prior extenders such as `font-lock-extend-region-wholelines` ;; do not leave `font-lock-end` at a line terminus, as usually they do, then the search ;; region bisects the text of the line, which means the text of a fontification segment ;; (a Breccian document contains nothing else), and each segment covers the whole of its lines. (end-of-line)); Thus far at least the present segment must extend; extend it now, ;;; that `re-search-forward` (below) must miss its leader. (let (is-changed) (if (re-search-forward brec-seg-start-pattern nil t); Cf. `brec-seg-end`. (end-of-line 0); Moving to the end of the previous line. (goto-char (point-max))) (when (< font-lock-end (point)) (set 'font-lock-end (point)) (setq is-changed t)) is-changed)) (defun brec-extend-search-up () "Ensures that ‘font-lock-beg’ bisects no fontification segment, moving it backward in the buffer as necessary. Returns nil if no change was required, non-nil otherwise." (goto-char font-lock-beg) (end-of-line); That `re-search-backward` (below) finds any leader on the present line. (let (is-changed) (if (re-search-backward brec-seg-start-pattern nil t) (beginning-of-line) (goto-char (point-min))) (when (> font-lock-beg (point)) (set 'font-lock-beg (point)) (setq is-changed t)) is-changed)) (defvar brec-f); [GVF] (defface brec-forbidden-whitespace `((t . (:inherit font-lock-warning-face :inverse-video t))) "\ The face for disallowed, horizontal whitespace characters." :group 'breccia) (defun brec-forward-paragraph () "A Breccian variant of the ‘forward-paragraph’ command. Moves forward to the next paragraph, as defined by ‘brec-interparagraph-line-offset’." (interactive "^") (brec-move-by-lines (brec-interparagraph-line-offset 1) t "next line")) (defvar brec-g); [GVF] (defface brec-generic-bullet `((t . (:inherit (brec-bullet font-lock-keyword-face)))) "\ The face for the bullet of a generic point." :group 'breccia) (defface brec-generic-bullet-punctuation `((t . (:inherit brec-generic-bullet :weight normal))) "\ The face for non-alphanumeric characters in the bullet of a generic point." :group 'breccia) (defun brec-interparagraph-line-offset (direction) "Returns the offset of the next line in DIRECTION (1 or -1) that has equal or less indentation, or nil if there is none. If point is on a blank line, however, then this function simply gives the offset of the next non-empty line or terminal line of the buffer. For this purpose a blank line is defined by ‘brec-line-is-blank’, and an empty line has no characters at all." (if (brec-line-is-blank) (brec-line-count direction 'ignore 'brec-t) (brec-line-count direction '> '<=))) (defun brec-keywords () "Returns the value of ‘font-lock-keywords’ to use for highlighting Breccian text." (list ;; ═══════════ ;; Aside point ;; ═══════════ ;; An aside point starts with a perfectly indented (PI) bullet comprising one slash (/). (list "^ \\{4\\}*\\(/\\)\\(?: +\\|$\\)"; (1) Anchoring on the bullet. ;; ┈──────┘ ;; PI '(1 'brec-aside-bullet); [QBF] (list; (3, anchored highlighter) Usually a descriptor follows the bullet, "\\(\\(?:.\\|\n\\)+\\)"; extending thence to the end of the point head. '(brec-seg-end); (2, pre-form) Making the search region cover the whole of it. [PSE] nil '(1 'brec-aside-descriptor))); [QBF] ;; ═════════════ ;; Command point ;; ═════════════ ;; A command point starts with a perfectly indented (PI) bullet comprising one colon (:). (list "^ \\{4\\}*\\(:\\)\\(?: +\\|$\\)"; (1) Anchoring on the bullet. ;; ┈──────┘ ;; PI '(1 'brec-command-bullet); [QBF] ;; Descriptor ;; ────────── (list; (3, anchored highlighter) Usually a descriptor follows the bullet, "\\(\\(?:.\\|\n\\)+\\)"; extending thence to the end of the point head. '(setq; (2, pre-form) brec-f (point); Saving the start of search region. brec-g (brec-seg-end)); Saving the limit of the present fontification segment and ;;; returning it, so extending the search region over the whole descriptor. [PSE] '(goto-char brec-f); (4, post-form) Repositioning for the next anchored highlighter, below. '(1 'brec-command-descriptor)); [QBF] ;; Referential command ;; ─────────────────── (list; (6, anchored highlighter) (mapconcat 'identity brec-command-matcher-components ""); Concatenating all the '(progn; (5, pre-form) components to one string. (while (progn (backward-char) ; Bringing the bullet ‘:’ (not (char-equal ?: (char-after))))); into the search region brec-g); and (again) ensuring it extends over the whole descriptor. nil '(1 'brec-command-keyword t t) '(2 'brec-command-keyword t t); [QBF] '(3 'brec-command-keyword t t))) ;; ═══════ ;; Divider ;; ═══════ ;; A divider starts with a perfectly indented (PI) drawing or inversion sequence. (let* ((drawing-char "[\u2500-\u2587\u2589-\u258F\u2591-\u259F]") (drawing-i (concat "\\(" drawing-char "+\\(?: +" drawing-char "+\\)*\\)")) ;;; Capturing (i) a sequence of `drawing-char` inclusive of embedded spaces, ;;; yet exclusive of embedded newlines. (labeling-char "[^[:space:]\u2500-\u259F]") ;;; A division labeling character exclusive of whitespace. (labeling (concat labeling-char "+\\(?: +" labeling-char "+\\)*")) ;;; A sequence of `labeling-char` inclusive of embedded spaces, ;;; yet exclusive of embedded newlines. (labeling-i (concat "\\(" labeling "\\)")) ; Capturing (i) an instance of labeling. (titling-i (concat "\n +\\(" labeling "\\)")); Capturing (i) an instance of titling. (inversion-mark "[\u2588\u2590]") (inversion-iii; Capturing (i) an inversion mark, (ii) any `labeling` together with ;; any space characters around it, and (iii) any full block character. (concat "\\(" inversion-mark "\\)\\( *\\(?:" labeling " *\\)?\\)\\(\u2588\\)?"))) (list (concat "^ \\{4\\}*\\(?:" drawing-i "\\|" inversion-iii "\\)"); (1) Anchoring on the PI sequence. ;; └────────┘ ;; PI '(1 'brec-divider nil t); `drawing-i` '(2 'brec-divider nil t) ; i, '(3 'brec-division-inverse-labeling nil t); ii and '(4 'brec-divider nil t) ; iii of `inversion-iii`. [QBF] ;; (3, anchored highlighter) Thence it may include any mix of drawing, titling, labeling and in- (list (concat drawing-i "\\|" titling-i "\\|" labeling-i "\\|" inversion-iii); version sequences. '(brec-seg-end); (2, pre-form) Making the search region cover a whole segment of it. [PSE] nil; (post-form) '(1 'brec-divider nil t); `drawing-i` '(2 'brec-division-titling nil t); `titling-i` '(3 'brec-division-label nil t); `labeling-i` '(4 'brec-divider nil t) ; i, '(5 'brec-division-inverse-labeling nil t); ii and '(6 'brec-divider nil t)))) ; iii of `inversion-iii`. [QBF] ;; ════════════════ ;; Free form bullet of an alarm, task or generic point ;; ════════════════ (list (let ((rough-bullet-pattern; The best a regexp can do here, allowing some false matches. (concat "^ \\{4\\}*\\(\\\\*"; Perfectly indented (PI), the bullet starts with ;; ┈──────┘ └───┘ zero or more backslashes (\⋯) and a character ;; PI \⋯ that is neither whitespace nor a backslash: ;; "\\(?:[[:alnum:]]+ *\\|[^[:alnum:][:space:]\\][\u00A0]*\\)" ;; It ends just before either a) a space that directly after a non-alphanumeric, non-space ;; character, or b) a newline. Note that a no-break space (Unicode A0) will not end it. "\\(?:[[:alnum:]]+ *\\|[^[:alnum:][:space:]]+[\u00A0]*\\)*\\)")) char-first char-last is-match-changed length m1-beg m1-end m2-beg m2-end match-last match-end) (lambda (limit); Seek the next such bullet. (catch 'to-fontify (while (re-search-forward rough-bullet-pattern limit t); Starting the search on this naive (setq match-end (match-end 0) ; pattern, thence ensure each match m1-beg (match-beginning 1) ; is correct, as follows: m1-end match-end m2-beg nil m2-end nil is-match-changed nil) (let ((end m1-end)); Trim from the match any unwanted end boundary missed above. ;;; It is either a delimiter of inline commentary (regexp pattern ‘ +\\+’) ;;; or a sequence of trailing space at the line end (‘ +$’). Trim it thus: (while (char-equal (char-before end) ?\\); For any trailing backslashes captured, (setq end (1- end))) ; scan backward past them. (while (char-equal (char-before end) ?\s); For any trailing space characters, (setq end (1- end) ; scan backward past them, and trim m1-end end ; the whole from the captive group. is-match-changed t))) (when (catch 'is-free-form-bullet (setq length (- m1-end m1-beg) match-last (1- m1-end); The last position in the match, that is. char-last (char-after match-last)) ;; Task bullet ;; ─────────── (when (char-equal ?+ char-last) (if (= length 1) (set 'brec-f 'brec-task-bullet-singleton) (setq m2-end m1-end m2-beg match-last m1-end m2-beg is-match-changed t) (set 'brec-f 'brec-task-bullet) (set 'brec-g 'brec-task-bullet-terminator)) (throw 'is-free-form-bullet t)) ;; Alarm bullet ;; ──────────── (when (and (> length 1) (char-equal ?! char-last) (char-equal ?! (char-before match-last))) (if (= length 2) (set 'brec-f 'brec-alarm-bullet-singleton) (setq m2-end m1-end m2-beg (1- match-last) m1-end m2-beg is-match-changed t) (set 'brec-f 'brec-alarm-bullet) (set 'brec-g 'brec-alarm-bullet-terminator)) (throw 'is-free-form-bullet t)) ;; Miscapture of non-bullet (divider) | tightly constrained (aside|command) bullet ;; ────────── (setq char-first (char-after m1-beg)) (when (and (= 1 length) ; When an aside or command bullet (or (char-equal ?/ char-first) ; is captured, abandon the match (char-equal ?: char-first))); and continue seeking. (throw 'is-free-form-bullet nil)) (when (and (>= char-first ?\u2500) ; When a divider mark leads the match, (<= char-first ?\u259F)); abandon the match and continue seeking. (throw 'is-free-form-bullet nil)) ;; Generic bullet ;; ────────────── (set 'brec-f 'brec-generic-bullet) t) (when is-match-changed (set-match-data (list (match-beginning 0) match-end m1-beg m1-end m2-beg m2-end (current-buffer)))) (throw 'to-fontify t))) nil))) '(1 brec-f) '(2 brec-g nil t)) (cons; Reface the non-alphanumeric characters of free-form bullets. (let (face match-beg match-end) (lambda (limit) (setq match-beg (point)); Presumptively. (catch 'to-reface (while (< match-beg limit) (setq face (get-text-property match-beg 'face) match-end (next-single-property-change match-beg 'face (current-buffer) limit)) (when (or (eq face 'brec-generic-bullet) (eq face 'brec-task-bullet) (eq face 'brec-alarm-bullet)) (goto-char match-beg) (when (re-search-forward "[^[:alnum:] \u00A0]+" match-end t) (set 'brec-f (intern (concat (symbol-name face) "-punctuation"))) ;;; To the punctuation variant of the face. (throw 'to-reface t))) (setq match-beg match-end)) nil))) '(0 brec-f t)) ;;; ── D e f e r r e d f o n t i f i c a t i o n ─────────────────────────────────────────────────── ;; ══════════ ;; Commentary ;; ══════════ ;; Commentary is delimited per line by one or more backslashes (\⋯) together isolated ;; in whitespace. Usually the delimiter is followed by commentary content (C) too. (list "\\(?:^\\| \\)\\(\\\\+\\)\\( +.*\\)?$"; [RWC, SPC] ;; └───────┘ └──────┘ ;; \⋯ C '(1 'font-lock-comment-delimiter-face t) '(2 'font-lock-comment-face t t)); [OCF] ;; Moreover where a line of pure commentary is delimited by two or more backslashes (\\⋯), ;; any content is taken to be a block label (L). (cons "^ *\\\\\\{2,\\}\\( +.+\\)$" '(1 'brec-comment-block-label t)); [OCF, QBF, RWC, SPC] ;;; └──────────┘ └──────┘ ;;; \\⋯ L ;; ════════════════════ ;; Forbidden whitespace ;; ════════════════════ (cons "[\t\u2000-\u200A\u202F\u205F\u3000]" '(0 'brec-forbidden-whitespace t)))); [QBF] ;;; 9, 2000 - 200A, 202F, 205F, 3000 ;;; ;;; No attempt is made here to reface any no-break space (Unicode A0) that appears ;;; in a forbidden context. It will already have a distinct appearance, however, ;;; owing to the setting herein of `nobreak-char-display`, q.v. (defun brec-line-count (direction skip good) "Returns the number of lines in DIRECTION (1 or -1) that either are empty or satisfy relation SKIP between their indentation and the original indentation, and end with a line whose indentation satisfies predicate GOOD." ;; Modified from the original code posted by ShreevatsaR. [SR] (let ((starting-indentation (current-indentation)) (lines-moved direction)) (save-excursion (while (and (zerop (forward-line direction)) (or (eolp); Skipping empty lines and SKIP lines. (funcall skip (current-indentation) starting-indentation))) (setq lines-moved (+ lines-moved direction))) ;; Unable now to go further, which case is it? (if (funcall good (current-indentation) starting-indentation) lines-moved nil)))) (defun brec-line-is-blank () "Answers whether the line at point contains at most whitespace." ;; Modified from the original code posted by PythonNut. https://emacs.stackexchange.com/a/16826/21090 (string-match-p "\\`\\s-*$" (thing-at-point 'line t))) (defun brec-move-by-lines (count to-preserve-column default-label) "Go forward COUNT lines, or backward if COUNT is negative. If COUNT is nil, then instead tell the user there is no DEFAULT-LABEL (string) to move to." ;; Modified from the original code posted by ShreevatsaR. [SR] (if (not count) (message "No %s to move to." default-label) (let ((saved-column (current-column))) (forward-line count) (move-to-column (if to-preserve-column saved-column (current-indentation)))))) (defun brec-seg-end () "Returns the end position of the present fontification segment, provided that point is *not* at the beginning of the segment. If point is at the beginning, then the result is undefined." (save-excursion (if (re-search-forward brec-seg-start-pattern nil t); Cf. `brec-extend-search-down`. (end-of-line 0); Moving to the end of the previous line. (goto-char (point-max))) (point))) (defun brec-set-for-buffer (variable value) "Sets VARIABLE (a symbol) to VALUE. Signals an error if the setting is not buffer local." (set variable value) (cl-assert (local-variable-p variable))) (defun brec-t (&rest _args) "Ignores any arguments and returns t. In other words, the opposite of ‘ignore’." t) (defface brec-task-bullet `((t . (:inherit (brec-bullet font-lock-function-name-face)))) "\ The face for the bullet of a task point." :group 'breccia) (defface brec-task-bullet-punctuation `((t . (:inherit brec-task-bullet :weight normal))) "\ The face for any non-alphanumeric character of a task bullet other than those of ‘brec-task-bullet-singleton’ and ‘brec-task-bullet-terminator’." :group 'breccia) (defface brec-task-bullet-singleton `((t . (:inherit brec-task-bullet))) "\ The face for a task bullet that comprises ‘+’ alone." :group 'breccia) (defface brec-task-bullet-terminator `((t . (:inherit font-lock-comment-face))) "\ The face for the bullet terminator ‘+’ of a task point. Cf. ‘brec-task-bullet-singleton’." :group 'breccia) ;; ══════════════════════════════════════════════════════════════════════════════════════════════════════ (define-derived-mode breccia-mode text-mode "Breccia" "\ A major mode for editing Breccian text. Home page URL ‘http://reluk.ca/project/Breccia/Emacs/’ User instructions URL ‘http://reluk.ca/project/Breccia/Emacs/breccia-mode.el’" :group 'breccia (modify-syntax-entry ?\u00A0 " " breccia-mode-syntax-table); Giving to no-break spaces (Unicode A0) (setq-local nobreak-char-display t); whitespace syntax, and a distinct look as defined by the Emacs ;;; standard face `nobreak-space`. [SF] ;; Define paragraph bounds, e.g. for sake of the `fill-paragraph` command ;; ─────────────────────── ;;; (set 'use-hard-newlines t); It says, ‘Automatically becomes permanently buffer-local when set.’ ;;;;; Unexpectedly that wrecks rather than helps the following. (setq-local paragraph-start (concat brec-seg-start-pattern ".*$")) (setq-local paragraph-separate "^ *\\(?:\u00A0.*\\|\\\\+\\( +.*\\)?\\)?$") ;;; Blank lines, indentation blinds and block commentary, that is. ;; Remap commands to their Breccian variants ;; ────────────── (let ((m breccia-mode-map)) (define-key m [remap backward-paragraph] 'brec-backward-paragraph) (define-key m [remap forward-paragraph] 'brec-forward-paragraph)) ;; Set up Font Lock ;; ──────────────── ;;; (brec-set-for-buffer 'font-lock-multiline t) ;;;;; This setting does not, however, seem necessary; nor does the documentation imply that it would be. ;;;;; Should fontification ever depend on *subsequent* lines, there I think this setting would at least ;;;;; speed the response to changes. Meantime, it seems that `brec-extend-search` alone will suffice: (add-hook 'font-lock-extend-region-functions 'brec-extend-search t t) ; [FLE] (brec-set-for-buffer 'font-lock-defaults '(brec-keywords))) (provide 'breccia-mode) ;; NOTES ;; ───── ;; BUG This code is incorrect. ;; ;; D ·· Descriptor. http://reluk.ca/project/Breccia/language_definition.brec § Descriptor ;; ;; FLE Font Lock extension. The alternative to `font-lock-extend-region-functions`, namely the ;; little used `font-lock-extend-after-change-region-function`, appears to be a design error. ;; https://lists.gnu.org/archive/html/bug-gnu-emacs/2015-03/msg00818.html ;; ;; FV · Suppressing sporadic compiler warnings ‘reference to free variable’ ;; or ‘assignment to free variable’. ;; ;; GVF A global variable for the use of fontifiers, e.g. from within forms they quote and pass ;; to Font Lock to be evaluated outside of their lexical scope. ;; ;; OCF Overrides in comment fontification. The fontification of a comment must override (t) ;; any fontification of its containing head, and must therefore follow it in `brec-keywords`. ;; ;; We might have tried fontifying the commentary using the syntax system, which runs earlier. ;; Not by mere syntax tabulation, which is unable to grasp the form of Breccian commentary; ;; rather we would probably have used the macro `syntax-propertize-rules` to set syntax properties ;; on the comment delimiters. But then could the `subexp-highlighters` for the containing fractum ;; have worked around the comments, e.g. with `override` at nil? [SBF] ;; ;; PSE Pre-form search extension: extending the end boundary of the search region for multi-line ;; anchoring. The manual warns, ‘It is generally a bad idea to return a position greater than ;; the end of the line’ [SBF]. But this appears to be a bug in the manual. ;; https://stackoverflow.com/a/9456757/2402790 ;; ;; QBF Quoting of Breccian face references. Their quoting is required for passage to evaluators, ;; e.g. in the case of a Font Lock *facespec*. [QFS] ;; ;; That might seem obvious, but many packages define a namesake variable for each face symbol. ;; ‘In the vast majority of cases, this is not necessary’, ;; `https://www.gnu.org/software/emacs/manual/html_node/elisp/Defining-Faces.html`. ;; ‘Simply using faces directly is enough’, ;; `http://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/font-lock.el`. ;; ;; QFS Quote each *facespec* formed as either a face symbol or a list, because Font lock evaluates it. ;; https://www.gnu.org/software/emacs/manual/html_node/elisp/Search_002dbased-Fontification.html ;; ;; RWC Refontifying whitespace in comments. It too must be refontified in order to override [OCF] ;; any improper fontification arising from inverse labeling or user customization of faces. ;; ;; SBF Search-based fontification. ;; https://www.gnu.org/software/emacs/manual/html_node/elisp/Search_002dbased-Fontification.html ;; ;; SF · Standard faces: `https://www.gnu.org/software/emacs/manual/html_node/emacs/Standard-Faces.html` ;; and § Standard faces at `http://git.savannah.gnu.org/cgit/emacs.git/tree/lisp/faces.el`. ;; ;; SPC Synchronized pattern of commentary. Marking an instance of a pattern or anti-pattern, ;; one of several that together are maintained in synchrony. ;; ;; SR · https://emacs.stackexchange.com/a/27169/21090 ;;; Copyright © 2019-2020 Michael Allan and contributors. Licence MIT.