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nix-mode: set syntax and font properties for multiline strings

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This commit is contained in:
Thomas Tuegel 2016-04-01 17:38:45 -05:00
parent 6e120b76ee
commit a828fe5b46
1 changed files with 84 additions and 2 deletions
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86
misc/emacs/nix-mode.el
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@ -8,6 +8,20 @@
;;; Code:
(defun nix-syntax-match-antiquote (limit)
(let ((pos (next-single-char-property-change (point) 'nix-syntax-antiquote
nil limit)))
(when (and pos (> pos (point)))
(goto-char pos)
(let ((char (char-after pos)))
(pcase char
(`?$
(forward-char 2))
(`?}
(forward-char 1)))
(set-match-data (list pos (point)))
t))))
(defconst nix-font-lock-keywords
'("\\_<if\\_>" "\\_<then\\_>" "\\_<else\\_>" "\\_<assert\\_>" "\\_<with\\_>"
"\\_<let\\_>" "\\_<in\\_>" "\\_<rec\\_>" "\\_<inherit\\_>" "\\_<or\\_>"
@ -26,7 +40,8 @@
("<[a-zA-Z0-9._\\+-]+\\(/[a-zA-Z0-9._\\+-]+\\)*>"
. font-lock-constant-face)
("[a-zA-Z0-9._\\+-]*\\(/[a-zA-Z0-9._\\+-]+\\)+"
. font-lock-constant-face))
. font-lock-constant-face)
(nix-syntax-match-antiquote 0 font-lock-preprocessor-face t))
"Font lock keywords for nix.")
(defvar nix-mode-syntax-table
@ -38,6 +53,67 @@
table)
"Syntax table for Nix mode.")
(defun nix-syntax-propertize-escaped-antiquote ()
"Set syntax properies for escaped antiquote marks."
nil)
(defun nix-syntax-propertize-multiline-string ()
"Set syntax properies for multiline string delimiters."
(let* ((start (match-beginning 0))
(end (match-end 0))
(context (save-excursion (save-match-data (syntax-ppss start))))
(string-type (nth 3 context)))
(pcase string-type
(`t
;; inside a multiline string
;; ending multi-line string delimiter
(put-text-property (1- end) end
'syntax-table (string-to-syntax "|")))
(`nil
;; beginning multi-line string delimiter
(put-text-property start (1+ start)
'syntax-table (string-to-syntax "|"))))))
(defun nix-syntax-propertize-antiquote ()
"Set syntax properties for antiquote marks."
(let* ((start (match-beginning 0)))
(put-text-property start (1+ start)
'syntax-table (string-to-syntax "|"))
(put-text-property start (+ start 2)
'nix-syntax-antiquote t)))
(defun nix-syntax-propertize-close-brace ()
"Set syntax properties for close braces.
If a close brace `}' ends an antiquote, the next character begins a string."
(let* ((start (match-beginning 0))
(end (match-end 0))
(context (save-excursion (save-match-data (syntax-ppss start))))
(open (nth 1 context)))
(when open ;; a corresponding open-brace was found
(let* ((antiquote (get-text-property open 'nix-syntax-antiquote)))
(when antiquote
(put-text-property (+ start 1) (+ start 2)
'syntax-table (string-to-syntax "|"))
(put-text-property start (1+ start)
'nix-syntax-antiquote t))))))
(defun nix-syntax-propertize (start end)
"Special syntax properties for Nix."
;; search for multi-line string delimiters
(goto-char start)
(remove-text-properties start end '(syntax-table nil nix-syntax-antiquote nil))
(funcall
(syntax-propertize-rules
("''\\${"
(0 (ignore (nix-syntax-propertize-escaped-antiquote))))
("''"
(0 (ignore (nix-syntax-propertize-multiline-string))))
("\\${"
(0 (ignore (nix-syntax-propertize-antiquote))))
("}"
(0 (ignore (nix-syntax-propertize-close-brace)))))
start end))
(defun nix-indent-line ()
"Indent current line in a Nix expression."
(interactive)
@ -69,7 +145,13 @@ The hook `nix-mode-hook' is run when Nix mode is started.
(set-syntax-table nix-mode-syntax-table)
;; Font lock support.
(setq font-lock-defaults '(nix-font-lock-keywords nil nil nil nil))
(setq-local font-lock-defaults '(nix-font-lock-keywords nil nil nil nil))
;; Special syntax properties for Nix
(setq-local syntax-propertize-function 'nix-syntax-propertize)
;; Look at text properties when parsing
(setq-local parse-sexp-lookup-properties t)
;; Automatic indentation [C-j].
(set (make-local-variable 'indent-line-function) 'nix-indent-line)