branch: externals/bnf-mode
commit 5a483ed7ad1b846db3faa2410932ccb796b9956c
Author: Serghei Iakovlev <serg...@phalconphp.com>
Commit: Serghei Iakovlev <serg...@phalconphp.com>
Introduce ALGOL 60 comments style
---
bnf-mode.el | 107 +++++++++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 84 insertions(+), 23 deletions(-)
diff --git a/bnf-mode.el b/bnf-mode.el
index 77c1b0a..0637dfa 100644
--- a/bnf-mode.el
+++ b/bnf-mode.el
@@ -84,6 +84,23 @@
:type 'hook
:group 'bnf)
+(defcustom bnf-mode-algol-commets-style nil
+ "Non-nil means use for BNF comments style introduced in ALGOL 60.
+
+For the purpose of including text among the symbols of a program the following
+\"comment\" conventions will hold:
+
+ :------------------------------------------------:------------------:
+ | The sequence of basic symbols: | is equivalent to |
+ :------------------------------------------------:------------------:
+ | ; comment <any sequence not containing ;>; | ; |
+ | begin comment <any sequence not containing ;>; | begin |
+ :------------------------------------------------:------------------:
+
+Note: Enabling this feature disables ABNF/EBN comments style (just \";\")."
+ :group 'bnf
+ :type 'boolean)
+
;;; Specialized rx
@@ -160,33 +177,43 @@ See `rx' documentation for more information about REGEXPS
param."
(let ((table (make-syntax-table)))
;; Give CR the same syntax as newline
(modify-syntax-entry ?\^m "> b" table)
- ;; Comments setup
- (modify-syntax-entry ?\; "<" table)
- (modify-syntax-entry ?\n ">" table)
+
;; Treat ::= as sequence of symbols
- (modify-syntax-entry ?\: "_" table)
- (modify-syntax-entry ?\= "_" table)
+ (modify-syntax-entry ?\: "_" table)
+ (modify-syntax-entry ?\= "_" table)
+
;; Treat | as a symbol
- (modify-syntax-entry ?\| "_" table)
+ (modify-syntax-entry ?\| "_" table)
+
;; In BNF there are no strings
;; so treat ' and " as a symbols
- (modify-syntax-entry ?\" "_" table)
- (modify-syntax-entry ?\' "_" table)
+ (modify-syntax-entry ?\" "_" table)
+ (modify-syntax-entry ?\' "_" table)
+
;; In BNF there are no grouping
;; brackets except angle ones
- (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 ?\( "_" table)
+ (modify-syntax-entry ?\) "_" table)
+ (modify-syntax-entry ?\{ "_" table)
+ (modify-syntax-entry ?\} "_" table)
+ (modify-syntax-entry ?\[ "_" table)
+ (modify-syntax-entry ?\] "_" table)
+
;; Group angle brackets
- (modify-syntax-entry ?\< "(>" table)
- (modify-syntax-entry ?\> ")<" table)
+ (modify-syntax-entry ?\< "(>" table)
+ (modify-syntax-entry ?\> ")<" table)
+
+ ;; Comments setup
+ (if bnf-mode-algol-commets-style
+ (modify-syntax-entry ?\; ">" table)
+ (progn
+ (modify-syntax-entry ?\; "<" table)
+ (modify-syntax-entry ?\n ">" table)))
+
table)
"Syntax table in use in `bnf-mode' buffers.")
-(defun bnf--syntax-propertize (start end)
+(defun bnf--bnf-syntax-propertize-function (start end)
"Apply syntax table properties to special constructs in region START to END.
Currently handled:
@@ -205,18 +232,52 @@ Currently handled:
;;; Initialization
+(defconst bnf--bnf-syntax-propertize-macro
+ (syntax-propertize-rules
+
("\\(?:begin\\_>\\|;\\)\\(?:$\\|\\s-\\|\n\\)+\\(\\(?:comment\\_>\\)[^;]*;\\)"
+ (1 "<")))
+ "Fontify comments in ALGOL 60 style.
+Provide a macro to apply syntax table properties to comments in ALGOL 60 style.
+Will used only if `bnf-mode-algol-commets-style' is set to t")
+
;;;###autoload
(define-derived-mode bnf-mode prog-mode "BNF"
"A major mode for editing BNF grammars."
:syntax-table bnf-mode-syntax-table
:group 'bnf-mode
- ;; Comments setup.
+
+ ;; Comments setup
(setq-local comment-use-syntax nil)
- (setq-local comment-start "; ")
- (setq-local comment-end "")
- (setq-local comment-start-skip "\\(?:\\(\\W\\|^\\);+\\)\\s-*")
- ;; Tune up syntax `syntax-table'
- (setq-local syntax-propertize-function #'bnf--syntax-propertize)
+ (if bnf-mode-algol-commets-style
+ (progn
+ (setq-local comment-start "; comment ")
+ (setq-local comment-end ";")
+ (setq-local comment-start-skip "\\(?:\\(\\W\\|^\\)comment\\_>\\)\\s-+")
+ (setq-local syntax-propertize-function
+ bnf--bnf-syntax-propertize-macro))
+ (progn
+ (setq-local comment-start "; ")
+ (setq-local comment-end "")
+ (setq-local comment-start-skip "\\(?:\\(\\W\\|^\\);+\\)\\s-+")
+ (setq-local syntax-propertize-function
+ #'bnf--bnf-syntax-propertize-function)))
+
+ ;; Basically `syntax-propertize-function' is a construct which belongs
+ ;; to `font-lock'. But correct indentation depends on
+ ;; syntax properties of the text, and that should ideally be
+ ;; independent of font-lock being activated or not.
+ ;;
+ ;; For `bnf-mode', this means that with `font-lock' disabled, we wont
+ ;; have our syntax properties set correctly, and indentation will
+ ;; suffer.
+ ;;
+ ;; To patch our way around this, we issue a `syntax-propertize' call
+ ;; manually, `font-lock' enabled or not.
+ (with-silent-modifications
+ (if bnf-mode-algol-commets-style
+ (funcall syntax-propertize-function (point-min) (point-max))
+ (bnf--bnf-syntax-propertize-function (point-min) (point-max))))
+
;; Font locking
(setq font-lock-defaults
'(
