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lix/misc/emacs/nix-mode.el
Eelco Dolstra 95c74eae26 Allow dashes in identifiers
In Nixpkgs, the attribute in all-packages.nix corresponding to a
package is usually equal to the package name.  However, this doesn't
work if the package contains a dash, which is fairly common.  The
convention is to replace the dash with an underscore (e.g. "dbus-lib"
becomes "dbus_glib"), but that's annoying.  So now dashes are valid in
variable / attribute names, allowing you to write:

  dbus-glib = callPackage ../development/libraries/dbus-glib { };

and

  buildInputs = [ dbus-glib ];

Since we don't have a negation or subtraction operation in Nix, this
is unambiguous.
2012-09-27 15:49:20 -04:00

114 lines
3.3 KiB
EmacsLisp

(defun nix-mode ()
"Major mode for editing Nix expressions.
The following commands may be useful:
'\\[newline-and-indent]'
Insert a newline and move the cursor to align with the previous
non-empty line.
'\\[fill-paragraph]'
Refill a paragraph so that all lines are at most `fill-column'
lines long. This should do the right thing for comments beginning
with `#'. However, this command doesn't work properly yet if the
comment is adjacent to code (i.e., no intervening empty lines).
In that case, select the text to be refilled and use
`\\[fill-region]' instead.
The hook `nix-mode-hook' is run when Nix mode is started.
\\{nix-mode-map}
"
(interactive)
(kill-all-local-variables)
(setq major-mode 'nix-mode)
(setq mode-name "Nix")
(use-local-map nix-mode-map)
(set-syntax-table nix-mode-syntax-table)
;; Font lock support.
(setq font-lock-defaults '(nix-keywords nil nil nil nil))
;; Automatic indentation [C-j].
(make-local-variable 'indent-line-function)
(setq indent-line-function 'nix-indent-line)
;; Indenting of comments.
(make-local-variable 'comment-start)
(setq comment-start "# ")
(make-local-variable 'comment-end)
(setq comment-end "")
(make-local-variable 'comment-start-skip)
(setq comment-start-skip "\\(^\\|\\s-\\);?#+ *")
;; Filling of comments.
(make-local-variable 'adaptive-fill-mode)
(setq adaptive-fill-mode t)
(make-local-variable 'paragraph-start)
(setq paragraph-start "[ \t]*\\(#+[ \t]*\\)?$")
(make-local-variable 'paragraph-separate)
(setq paragraph-separate paragraph-start)
(run-hooks 'nix-mode-hook)
)
(defvar nix-mode-map nil
"Keymap for Nix mode.")
(setq nix-mode-map (make-sparse-keymap))
;(define-key nix-mode-map [tab] 'tab-to-tab-stop)
(defvar nix-keywords
'("\\<if\\>" "\\<then\\>" "\\<else\\>" "\\<assert\\>" "\\<with\\>"
"\\<let\\>" "\\<in\\>" "\\<rec\\>" "\\<inherit\\>" "\\<or\\>"
("\\<true\\>" . font-lock-builtin-face)
("\\<false\\>" . font-lock-builtin-face)
("\\<null\\>" . font-lock-builtin-face)
("\\<import\\>" . font-lock-builtin-face)
("\\<derivation\\>" . font-lock-builtin-face)
("\\<baseNameOf\\>" . font-lock-builtin-face)
("\\<toString\\>" . font-lock-builtin-face)
("\\<isNull\\>" . font-lock-builtin-face)
("[a-zA-Z][a-zA-Z0-9\\+-\\.]*:[a-zA-Z0-9%/\\?:@&=\\+\\$,_\\.!~\\*'-]+"
. font-lock-constant-face)
("\\<\\([a-zA-Z_][a-zA-Z0-9_'\-\.]*\\)[ \t]*="
(1 font-lock-variable-name-face nil nil))
("<[a-zA-Z0-9._\\+-]+\\(/[a-zA-Z0-9._\\+-]+\\)*>"
. font-lock-constant-face)
("[a-zA-Z0-9._\\+-]*\\(/[a-zA-Z0-9._\\+-]+\\)+"
. font-lock-constant-face)
))
(defvar nix-mode-syntax-table nil
"Syntax table for Nix mode.")
(if nix-mode-syntax-table
nil
(progn
(setq nix-mode-syntax-table (make-syntax-table))
(modify-syntax-entry ?/ ". 14" nix-mode-syntax-table)
(modify-syntax-entry ?* ". 23" nix-mode-syntax-table)
(modify-syntax-entry ?# "< b" nix-mode-syntax-table)
(modify-syntax-entry ?\n "> b" nix-mode-syntax-table)
))
(defun nix-indent-line ()
"Indent current line in a Nix expression."
(interactive)
(indent-relative-maybe))
(setq auto-mode-alist (cons '("\\.nix\\'" . nix-mode) auto-mode-alist))
(setq auto-mode-alist (cons '("\\.nix.in\\'" . nix-mode) auto-mode-alist))
(provide 'nix-mode)