lisp/progmodes/ruby-mode.el

   1 ;;; ruby-mode.el --- Major mode for editing Ruby files
   2
   3 ;; Copyright (C) 1994-2013 Free Software Foundation, Inc.
   4
   5 ;; Authors: Yukihiro Matsumoto
   6 ;;      Nobuyoshi Nakada
   7 ;; URL: http://www.emacswiki.org/cgi-bin/wiki/RubyMode
   8 ;; Created: Fri Feb  4 14:49:13 JST 1994
   9 ;; Keywords: languages ruby
  10 ;; Version: 1.2
  11
  12 ;; This file is part of GNU Emacs.
  13
  14 ;; GNU Emacs is free software: you can redistribute it and/or modify
  15 ;; it under the terms of the GNU General Public License as published by
  16 ;; the Free Software Foundation, either version 3 of the License, or
  17 ;; (at your option) any later version.
  18
  19 ;; GNU Emacs is distributed in the hope that it will be useful,
  20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22 ;; GNU General Public License for more details.
  23
  24 ;; You should have received a copy of the GNU General Public License
  25 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  26
  27 ;;; Commentary:
  28
  29 ;; Provides font-locking, indentation support, and navigation for Ruby code.
  30 ;;
  31 ;; If you're installing manually, you should add this to your .emacs
  32 ;; file after putting it on your load path:
  33 ;;
  34 ;;    (autoload 'ruby-mode "ruby-mode" "Major mode for ruby files" t)
  35 ;;    (add-to-list 'auto-mode-alist '("\\.rb$" . ruby-mode))
  36 ;;    (add-to-list 'interpreter-mode-alist '("ruby" . ruby-mode))
  37 ;;
  38 ;; Still needs more docstrings; search below for TODO.
  39
  40 ;;; Code:
  41
  42 (defgroup ruby nil
  43   "Major mode for editing Ruby code."
  44   :prefix "ruby-"
  45   :group 'languages)
  46
  47 (defconst ruby-block-beg-keywords
  48   '("class" "module" "def" "if" "unless" "case" "while" "until" "for" "begin" "do")
  49   "Keywords at the beginning of blocks.")
  50
  51 (defconst ruby-block-beg-re
  52   (regexp-opt ruby-block-beg-keywords)
  53   "Regexp to match the beginning of blocks.")
  54
  55 (defconst ruby-non-block-do-re
  56   (regexp-opt '("while" "until" "for" "rescue") 'symbols)
  57   "Regexp to match keywords that nest without blocks.")
  58
  59 (defconst ruby-indent-beg-re
  60   (concat "^\\(\\s *" (regexp-opt '("class" "module" "def")) "\\|"
  61           (regexp-opt '("if" "unless" "case" "while" "until" "for" "begin"))
  62           "\\)\\_>")
  63   "Regexp to match where the indentation gets deeper.")
  64
  65 (defconst ruby-modifier-beg-keywords
  66   '("if" "unless" "while" "until")
  67   "Modifiers that are the same as the beginning of blocks.")
  68
  69 (defconst ruby-modifier-beg-re
  70   (regexp-opt ruby-modifier-beg-keywords)
  71   "Regexp to match modifiers same as the beginning of blocks.")
  72
  73 (defconst ruby-modifier-re
  74   (regexp-opt (cons "rescue" ruby-modifier-beg-keywords))
  75   "Regexp to match modifiers.")
  76
  77 (defconst ruby-block-mid-keywords
  78   '("then" "else" "elsif" "when" "rescue" "ensure")
  79   "Keywords where the indentation gets shallower in middle of block statements.")
  80
  81 (defconst ruby-block-mid-re
  82   (regexp-opt ruby-block-mid-keywords)
  83   "Regexp to match where the indentation gets shallower in middle of block statements.")
  84
  85 (defconst ruby-block-op-keywords
  86   '("and" "or" "not")
  87   "Regexp to match boolean keywords.")
  88
  89 (defconst ruby-block-hanging-re
  90   (regexp-opt (append ruby-modifier-beg-keywords ruby-block-op-keywords))
  91   "Regexp to match hanging block modifiers.")
  92
  93 (defconst ruby-block-end-re "\\_<end\\_>")
  94
  95 (defconst ruby-defun-beg-re
  96   '"\\(def\\|class\\|module\\)"
  97   "Regexp to match the beginning of a defun, in the general sense.")
  98
  99 (defconst ruby-singleton-class-re
 100   "class\\s *<<"
 101   "Regexp to match the beginning of a singleton class context.")
 102
 103 (eval-and-compile
 104   (defconst ruby-here-doc-beg-re
 105   "\\(<\\)<\\(-\\)?\\(\\([a-zA-Z0-9_]+\\)\\|[\"]\\([^\"]+\\)[\"]\\|[']\\([^']+\\)[']\\)"
 106   "Regexp to match the beginning of a heredoc.")
 107
 108   (defconst ruby-expression-expansion-re
 109     "\\(?:[^\\]\\|\\=\\)\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)"))
 110
 111 (defun ruby-here-doc-end-match ()
 112   "Return a regexp to find the end of a heredoc.
 113
 114 This should only be called after matching against `ruby-here-doc-beg-re'."
 115   (concat "^"
 116           (if (match-string 2) "[ \t]*" nil)
 117           (regexp-quote
 118            (or (match-string 4)
 119                (match-string 5)
 120                (match-string 6)))))
 121
 122 (defconst ruby-delimiter
 123   (concat "[?$/%(){}#\"'`.:]\\|<<\\|\\[\\|\\]\\|\\_<\\("
 124           ruby-block-beg-re
 125           "\\)\\_>\\|" ruby-block-end-re
 126           "\\|^=begin\\|" ruby-here-doc-beg-re))
 127
 128 (defconst ruby-negative
 129   (concat "^[ \t]*\\(\\(" ruby-block-mid-re "\\)\\>\\|"
 130           ruby-block-end-re "\\|}\\|\\]\\)")
 131   "Regexp to match where the indentation gets shallower.")
 132
 133 (defconst ruby-operator-re "[-,.+*/%&|^~=<>:]\\|\\\\$"
 134   "Regexp to match operators.")
 135
 136 (defconst ruby-symbol-chars "a-zA-Z0-9_"
 137   "List of characters that symbol names may contain.")
 138
 139 (defconst ruby-symbol-re (concat "[" ruby-symbol-chars "]")
 140   "Regexp to match symbols.")
 141
 142 (defvar ruby-use-smie t)
 143
 144 (defvar ruby-mode-map
 145   (let ((map (make-sparse-keymap)))
 146     (unless ruby-use-smie
 147       (define-key map (kbd "M-C-b") 'ruby-backward-sexp)
 148       (define-key map (kbd "M-C-f") 'ruby-forward-sexp)
 149       (define-key map (kbd "M-C-q") 'ruby-indent-exp))
 150     (when ruby-use-smie
 151       (define-key map (kbd "M-C-d") 'smie-down-list))
 152     (define-key map (kbd "M-C-p") 'ruby-beginning-of-block)
 153     (define-key map (kbd "M-C-n") 'ruby-end-of-block)
 154     (define-key map (kbd "C-c {") 'ruby-toggle-block)
 155     map)
 156   "Keymap used in Ruby mode.")
 157
 158 (easy-menu-define
 159   ruby-mode-menu
 160   ruby-mode-map
 161   "Ruby Mode Menu"
 162   '("Ruby"
 163     ["Beginning of Block" ruby-beginning-of-block t]
 164     ["End of Block" ruby-end-of-block t]
 165     ["Toggle Block" ruby-toggle-block t]
 166     "--"
 167     ["Backward Sexp" ruby-backward-sexp
 168      :visible (not ruby-use-smie)]
 169     ["Backward Sexp" backward-sexp
 170      :visible ruby-use-smie]
 171     ["Forward Sexp" ruby-forward-sexp
 172      :visible (not ruby-use-smie)]
 173     ["Forward Sexp" forward-sexp
 174      :visible ruby-use-smie]
 175     ["Indent Sexp" ruby-indent-exp
 176      :visible (not ruby-use-smie)]
 177     ["Indent Sexp" prog-indent-sexp
 178      :visible ruby-use-smie]))
 179
 180 (defvar ruby-mode-syntax-table
 181   (let ((table (make-syntax-table)))
 182     (modify-syntax-entry ?\' "\"" table)
 183     (modify-syntax-entry ?\" "\"" table)
 184     (modify-syntax-entry ?\` "\"" table)
 185     (modify-syntax-entry ?# "<" table)
 186     (modify-syntax-entry ?\n ">" table)
 187     (modify-syntax-entry ?\\ "\\" table)
 188     (modify-syntax-entry ?$ "." table)
 189     (modify-syntax-entry ?? "_" table)
 190     (modify-syntax-entry ?_ "_" table)
 191     (modify-syntax-entry ?: "_" table)
 192     (modify-syntax-entry ?< "." table)
 193     (modify-syntax-entry ?> "." table)
 194     (modify-syntax-entry ?& "." table)
 195     (modify-syntax-entry ?| "." table)
 196     (modify-syntax-entry ?% "." table)
 197     (modify-syntax-entry ?= "." table)
 198     (modify-syntax-entry ?/ "." table)
 199     (modify-syntax-entry ?+ "." table)
 200     (modify-syntax-entry ?* "." table)
 201     (modify-syntax-entry ?- "." table)
 202     (modify-syntax-entry ?\; "." table)
 203     (modify-syntax-entry ?\( "()" table)
 204     (modify-syntax-entry ?\) ")(" table)
 205     (modify-syntax-entry ?\{ "(}" table)
 206     (modify-syntax-entry ?\} "){" table)
 207     (modify-syntax-entry ?\[ "(]" table)
 208     (modify-syntax-entry ?\] ")[" table)
 209     table)
 210   "Syntax table to use in Ruby mode.")
 211
 212 (defcustom ruby-indent-tabs-mode nil
 213   "Indentation can insert tabs in Ruby mode if this is non-nil."
 214   :type 'boolean
 215   :group 'ruby
 216   :safe 'booleanp)
 217
 218 (defcustom ruby-indent-level 2
 219   "Indentation of Ruby statements."
 220   :type 'integer
 221   :group 'ruby
 222   :safe 'integerp)
 223
 224 (defcustom ruby-comment-column (default-value 'comment-column)
 225   "Indentation column of comments."
 226   :type 'integer
 227   :group 'ruby
 228   :safe 'integerp)
 229
 230 (defcustom ruby-deep-arglist t
 231   "Deep indent lists in parenthesis when non-nil.
 232 Also ignores spaces after parenthesis when 'space."
 233   :type 'boolean
 234   :group 'ruby
 235   :safe 'booleanp)
 236
 237 (defcustom ruby-deep-indent-paren '(?\( ?\[ ?\] t)
 238   "Deep indent lists in parenthesis when non-nil.
 239 The value t means continuous line.
 240 Also ignores spaces after parenthesis when 'space."
 241   :group 'ruby)
 242
 243 (defcustom ruby-deep-indent-paren-style 'space
 244   "Default deep indent style."
 245   :options '(t nil space) :group 'ruby)
 246
 247 (defcustom ruby-encoding-map
 248   '((us-ascii       . nil)       ;; Do not put coding: us-ascii
 249     (shift-jis      . cp932)     ;; Emacs charset name of Shift_JIS
 250     (shift_jis      . cp932)     ;; MIME charset name of Shift_JIS
 251     (japanese-cp932 . cp932))    ;; Emacs charset name of CP932
 252   "Alist to map encoding name from Emacs to Ruby.
 253 Associating an encoding name with nil means it needs not be
 254 explicitly declared in magic comment."
 255   :type '(repeat (cons (symbol :tag "From") (symbol :tag "To")))
 256   :group 'ruby)
 257
 258 (defcustom ruby-insert-encoding-magic-comment t
 259   "Insert a magic Ruby encoding comment upon save if this is non-nil.
 260 The encoding will be auto-detected.  The format of the encoding comment
 261 is customizable via `ruby-encoding-magic-comment-style'.
 262
 263 When set to `always-utf8' an utf-8 comment will always be added,
 264 even if it's not required."
 265   :type 'boolean :group 'ruby)
 266
 267 (defcustom ruby-encoding-magic-comment-style 'ruby
 268   "The style of the magic encoding comment to use."
 269   :type '(choice
 270           (const :tag "Emacs Style" emacs)
 271           (const :tag "Ruby Style" ruby)
 272           (const :tag "Custom Style" custom))
 273   :group 'ruby
 274   :version "24.4")
 275
 276 (defcustom ruby-custom-encoding-magic-comment-template "# encoding: %s"
 277   "A custom encoding comment template.
 278 It is used when `ruby-encoding-magic-comment-style' is set to `custom'."
 279   :type 'string
 280   :group 'ruby
 281   :version "24.4")
 282
 283 (defcustom ruby-use-encoding-map t
 284   "Use `ruby-encoding-map' to set encoding magic comment if this is non-nil."
 285   :type 'boolean :group 'ruby)
 286
 287 ;;; SMIE support
 288
 289 (require 'smie)
 290
 291 ;; Here's a simplified BNF grammar, for reference:
 292 ;; http://www.cse.buffalo.edu/~regan/cse305/RubyBNF.pdf
 293 (defconst ruby-smie-grammar
 294   (smie-prec2->grammar
 295    (smie-merge-prec2s
 296     (smie-bnf->prec2
 297      '((id)
 298        (insts (inst) (insts ";" insts))
 299        (inst (exp) (inst "iuwu-mod" exp)
 300              ;; Somewhat incorrect (both can be used multiple times),
 301              ;; but avoids lots of conflicts:
 302              (exp "and" exp) (exp "or" exp))
 303        (exp  (exp1) (exp "," exp) (exp "=" exp)
 304              (id " @ " exp)
 305              (exp "." id))
 306        (exp1 (exp2) (exp2 "?" exp1 ":" exp1))
 307        (exp2 ("def" insts "end")
 308              ("begin" insts-rescue-insts "end")
 309              ("do" insts "end")
 310              ("class" insts "end") ("module" insts "end")
 311              ("for" for-body "end")
 312              ("[" expseq "]")
 313              ("{" hashvals "}")
 314              ("{" insts "}")
 315              ("while" insts "end")
 316              ("until" insts "end")
 317              ("unless" insts "end")
 318              ("if" if-body "end")
 319              ("case"  cases "end"))
 320        (formal-params ("opening-|" exp "closing-|"))
 321        (for-body (for-head ";" insts))
 322        (for-head (id "in" exp))
 323        (cases (exp "then" insts)
 324               (cases "when" cases) (insts "else" insts))
 325        (expseq (exp) );;(expseq "," expseq)
 326        (hashvals (id "=>" exp1) (hashvals "," hashvals))
 327        (insts-rescue-insts (insts)
 328                            (insts-rescue-insts "rescue" insts-rescue-insts)
 329                            (insts-rescue-insts "ensure" insts-rescue-insts))
 330        (itheni (insts) (exp "then" insts))
 331        (ielsei (itheni) (itheni "else" insts))
 332        (if-body (ielsei) (if-body "elsif" if-body)))
 333      '((nonassoc "in") (assoc ";") (right " @ ")
 334        (assoc ",") (right "=") (assoc "."))
 335      '((assoc "when"))
 336      '((assoc "elsif"))
 337      '((assoc "rescue" "ensure"))
 338      '((assoc ",")))
 339
 340     (smie-precs->prec2
 341      '((right "=")
 342        (right "+=" "-=" "*=" "/=" "%=" "**=" "&=" "|=" "^="
 343               "<<=" ">>=" "&&=" "||=")
 344        (left ".." "...")
 345        (left "+" "-")
 346        (left "*" "/" "%" "**")
 347        (left "&&" "||")
 348        (left "^" "&" "|")
 349        (nonassoc "<=>")
 350        (nonassoc ">" ">=" "<" "<=")
 351        (nonassoc "==" "===" "!=")
 352        (nonassoc "=~" "!~")
 353        (left "<<" ">>"))))))
 354
 355 (defun ruby-smie--bosp ()
 356   (save-excursion (skip-chars-backward " \t")
 357                   (or (bolp) (memq (char-before) '(?\; ?=)))))
 358
 359 (defun ruby-smie--implicit-semi-p ()
 360   (save-excursion
 361     (skip-chars-backward " \t")
 362     (not (or (bolp)
 363              (and (memq (char-before)
 364                         '(?\; ?- ?+ ?* ?/ ?: ?. ?, ?\[ ?\( ?\{ ?\\ ?& ?> ?< ?%
 365                           ?~ ?^))
 366                   ;; Make sure it's not the end of a regexp.
 367                   (not (eq (car (syntax-after (1- (point)))) 7)))
 368              (and (eq (char-before) ?\?)
 369                   (equal (save-excursion (ruby-smie--backward-token)) "?"))
 370              (and (eq (char-before) ?=)
 371                   (string-match "\\`\\s." (save-excursion
 372                                             (ruby-smie--backward-token))))
 373              (and (eq (char-before) ?|)
 374                   (member (save-excursion (ruby-smie--backward-token))
 375                           '("|" "||")))
 376              (and (eq (car (syntax-after (1- (point)))) 2)
 377                   (member (save-excursion (ruby-smie--backward-token))
 378                           '("iuwu-mod" "and" "or")))
 379              (save-excursion
 380                (forward-comment 1)
 381                (eq (char-after) ?.))))))
 382
 383 (defun ruby-smie--redundant-do-p (&optional skip)
 384   (save-excursion
 385     (if skip (backward-word 1))
 386     (member (nth 2 (smie-backward-sexp ";")) '("while" "until" "for"))))
 387
 388 (defun ruby-smie--opening-pipe-p ()
 389   (save-excursion
 390     (if (eq ?| (char-before)) (forward-char -1))
 391     (skip-chars-backward " \t\n")
 392     (or (eq ?\{ (char-before))
 393         (looking-back "\\_<do" (- (point) 2)))))
 394
 395 (defun ruby-smie--closing-pipe-p ()
 396   (save-excursion
 397     (if (eq ?| (char-before)) (forward-char -1))
 398     (and (re-search-backward "|" (line-beginning-position) t)
 399          (ruby-smie--opening-pipe-p))))
 400
 401 (defun ruby-smie--args-separator-p (pos)
 402   (and
 403    (< pos (line-end-position))
 404    (or (eq (char-syntax (preceding-char)) '?w)
 405        ;; FIXME: Check that the preceding token is not a keyword.
 406        ;; This isn't very important most of the time, though.
 407        (and (memq (preceding-char) '(?! ??))
 408             (eq (char-syntax (char-before (1- (point)))) '?w)))
 409    (save-excursion
 410      (goto-char pos)
 411      (or (and (eq (char-syntax (char-after)) ?w)
 412               (not (looking-at (regexp-opt '("unless" "if" "while" "until" "or"
 413                                              "else" "elsif" "do" "end" "and")
 414                                            'symbols))))
 415          (memq (syntax-after pos) '(7 15))
 416          (looking-at "[([]\\|[-+!~:]\\sw")))))
 417
 418 (defun ruby-smie--at-dot-call ()
 419   (and (eq ?w (char-syntax (following-char)))
 420        (eq (char-before) ?.)
 421        (not (eq (char-before (1- (point))) ?.))))
 422
 423 (defun ruby-smie--forward-token ()
 424   (let ((pos (point)))
 425     (skip-chars-forward " \t")
 426     (cond
 427      ((looking-at "\\s\"") ;A heredoc or a string.
 428       (if (not (looking-at "\n"))
 429           ""
 430         ;; Tokenize the whole heredoc as semicolon.
 431         (goto-char (scan-sexps (point) 1))
 432         ";"))
 433      ((and (looking-at "[\n#]")
 434            (ruby-smie--implicit-semi-p)) ;Only add implicit ; when needed.
 435       (if (eolp) (forward-char 1) (forward-comment 1))
 436       ";")
 437      (t
 438       (forward-comment (point-max))
 439       (cond
 440        ((looking-at ":\\s.+")
 441         (goto-char (match-end 0)) (match-string 0)) ;; bug#15208.
 442        ((and (< pos (point))
 443              (save-excursion
 444                (ruby-smie--args-separator-p (prog1 (point) (goto-char pos)))))
 445         " @ ")
 446        (t
 447         (let ((dot (ruby-smie--at-dot-call))
 448               (tok (smie-default-forward-token)))
 449           (when dot
 450             (setq tok (concat "." tok)))
 451           (cond
 452            ((member tok '("unless" "if" "while" "until"))
 453             (if (save-excursion (forward-word -1) (ruby-smie--bosp))
 454                 tok "iuwu-mod"))
 455            ((string-match-p "\\`|[*&]?\\'" tok)
 456             (forward-char (- 1 (length tok)))
 457             (setq tok "|")
 458             (cond
 459              ((ruby-smie--opening-pipe-p) "opening-|")
 460              ((ruby-smie--closing-pipe-p) "closing-|")
 461              (t tok)))
 462            ((and (equal tok "") (looking-at "\\\\\n"))
 463             (goto-char (match-end 0)) (ruby-smie--forward-token))
 464            ((equal tok "do")
 465             (cond
 466              ((not (ruby-smie--redundant-do-p 'skip)) tok)
 467              ((> (save-excursion (forward-comment (point-max)) (point))
 468                  (line-end-position))
 469               (ruby-smie--forward-token)) ;Fully redundant.
 470              (t ";")))
 471            (t tok)))))))))
 472
 473 (defun ruby-smie--backward-token ()
 474   (let ((pos (point)))
 475     (forward-comment (- (point)))
 476     (cond
 477      ((and (> pos (line-end-position)) (ruby-smie--implicit-semi-p))
 478       (skip-chars-forward " \t") ";")
 479      ((and (bolp) (not (bobp)))         ;Presumably a heredoc.
 480       ;; Tokenize the whole heredoc as semicolon.
 481       (goto-char (scan-sexps (point) -1))
 482       ";")
 483      ((and (> pos (point)) (not (bolp))
 484            (ruby-smie--args-separator-p pos))
 485       ;; We have "ID SPC ID", which is a method call, but it binds less tightly
 486       ;; than commas, since a method call can also be "ID ARG1, ARG2, ARG3".
 487       ;; In some textbooks, "e1 @ e2" is used to mean "call e1 with arg e2".
 488       " @ ")
 489      (t
 490       (let ((tok (smie-default-backward-token))
 491             (dot (ruby-smie--at-dot-call)))
 492         (when dot
 493           (setq tok (concat "." tok)))
 494         (when (and (eq ?: (char-before)) (string-match "\\`\\s." tok))
 495           (forward-char -1) (setq tok (concat ":" tok))) ;; bug#15208.
 496         (cond
 497          ((member tok '("unless" "if" "while" "until"))
 498           (if (ruby-smie--bosp)
 499               tok "iuwu-mod"))
 500          ((equal tok "|")
 501           (cond
 502            ((ruby-smie--opening-pipe-p) "opening-|")
 503            ((ruby-smie--closing-pipe-p) "closing-|")
 504            (t tok)))
 505          ((string-match-p "\\`|[*&]\\'" tok)
 506           (forward-char 1)
 507           (substring tok 1))
 508          ((and (equal tok "") (eq ?\\ (char-before)) (looking-at "\n"))
 509           (forward-char -1) (ruby-smie--backward-token))
 510          ((equal tok "do")
 511           (cond
 512            ((not (ruby-smie--redundant-do-p)) tok)
 513            ((> (save-excursion (forward-word 1)
 514                                (forward-comment (point-max)) (point))
 515                (line-end-position))
 516             (ruby-smie--backward-token)) ;Fully redundant.
 517            (t ";")))
 518          (t tok)))))))
 519
 520 (defun ruby-smie--indent-to-stmt ()
 521   (save-excursion
 522     (smie-backward-sexp ";")
 523     (cons 'column (smie-indent-virtual))))
 524
 525 (defun ruby-smie-rules (kind token)
 526   (pcase (cons kind token)
 527     (`(:elem . basic) ruby-indent-level)
 528     ;; "foo" "bar" is the concatenation of the two strings, so the second
 529     ;; should be aligned with the first.
 530     (`(:elem . args) (if (looking-at "\\s\"") 0))
 531     ;; (`(:after . ",") (smie-rule-separator kind))
 532     (`(:before . ";")
 533      (cond
 534       ((smie-rule-parent-p "def" "begin" "do" "class" "module" "for"
 535                            "while" "until" "unless"
 536                            "if" "then" "elsif" "else" "when"
 537                            "rescue" "ensure" "{")
 538        (smie-rule-parent ruby-indent-level))
 539       ;; For (invalid) code between switch and case.
 540       ;; (if (smie-parent-p "switch") 4)
 541       ))
 542     (`(:before . ,(or `"(" `"[" `"{"))
 543      (cond
 544       ((and (equal token "{")
 545             (not (smie-rule-prev-p "(" "{" "[" "," "=>" "=" "return" ";"))
 546             (save-excursion
 547               (forward-comment -1)
 548               (not (eq (preceding-char) ?:))))
 549        ;; Curly block opener.
 550        (ruby-smie--indent-to-stmt))
 551       ((smie-rule-hanging-p)
 552        ;; Treat purely syntactic block-constructs as being part of their parent,
 553        ;; when the opening statement is hanging.
 554        (let ((state (smie-backward-sexp 'halfsexp)))
 555          (when (eq t (car state)) (goto-char (cadr state))))
 556        (cons 'column  (smie-indent-virtual)))))
 557     (`(:after . " @ ") (smie-rule-parent))
 558     (`(:before . "do") (ruby-smie--indent-to-stmt))
 559     (`(,(or :before :after) . ".")
 560      (unless (smie-rule-parent-p ".")
 561        (smie-rule-parent ruby-indent-level)))
 562     (`(:before . ,(or `"else" `"then" `"elsif" `"rescue" `"ensure")) 0)
 563     (`(:before . ,(or `"when"))
 564      (if (not (smie-rule-sibling-p)) 0)) ;; ruby-indent-level
 565     (`(:after . ,(or "=" "iuwu-mod" "+" "-" "*" "/" "&&" "||" "%" "**" "^" "&"
 566                      "<=>" ">" "<" ">=" "<=" "==" "===" "!=" "<<" ">>"
 567                      "+=" "-=" "*=" "/=" "%=" "**=" "&=" "|=" "^=" "|"
 568                      "<<=" ">>=" "&&=" "||=" "and" "or"))
 569      (if (smie-rule-parent-p ";" nil) ruby-indent-level))
 570     (`(:before . "begin")
 571      (unless (save-excursion (skip-chars-backward " \t") (bolp))
 572        (smie-rule-parent)))
 573     ))
 574
 575 (defun ruby-imenu-create-index-in-block (prefix beg end)
 576   "Create an imenu index of methods inside a block."
 577   (let ((index-alist '()) (case-fold-search nil)
 578         name next pos decl sing)
 579     (goto-char beg)
 580     (while (re-search-forward "^\\s *\\(\\(class\\s +\\|\\(class\\s *<<\\s *\\)\\|module\\s +\\)\\([^\(<\n ]+\\)\\|\\(def\\|alias\\)\\s +\\([^\(\n ]+\\)\\)" end t)
 581       (setq sing (match-beginning 3))
 582       (setq decl (match-string 5))
 583       (setq next (match-end 0))
 584       (setq name (or (match-string 4) (match-string 6)))
 585       (setq pos (match-beginning 0))
 586       (cond
 587        ((string= "alias" decl)
 588         (if prefix (setq name (concat prefix name)))
 589         (push (cons name pos) index-alist))
 590        ((string= "def" decl)
 591         (if prefix
 592             (setq name
 593                   (cond
 594                    ((string-match "^self\." name)
 595                     (concat (substring prefix 0 -1) (substring name 4)))
 596                   (t (concat prefix name)))))
 597         (push (cons name pos) index-alist)
 598         (ruby-accurate-end-of-block end))
 599        (t
 600         (if (string= "self" name)
 601             (if prefix (setq name (substring prefix 0 -1)))
 602           (if prefix (setq name (concat (substring prefix 0 -1) "::" name)))
 603           (push (cons name pos) index-alist))
 604         (ruby-accurate-end-of-block end)
 605         (setq beg (point))
 606         (setq index-alist
 607               (nconc (ruby-imenu-create-index-in-block
 608                       (concat name (if sing "." "#"))
 609                       next beg) index-alist))
 610         (goto-char beg))))
 611     index-alist))
 612
 613 (defun ruby-imenu-create-index ()
 614   "Create an imenu index of all methods in the buffer."
 615   (nreverse (ruby-imenu-create-index-in-block nil (point-min) nil)))
 616
 617 (defun ruby-accurate-end-of-block (&optional end)
 618   "TODO: document."
 619   (let (state
 620         (end (or end (point-max))))
 621     (while (and (setq state (apply 'ruby-parse-partial end state))
 622                 (>= (nth 2 state) 0) (< (point) end)))))
 623
 624 (defun ruby-mode-variables ()
 625   "Set up initial buffer-local variables for Ruby mode."
 626   (setq indent-tabs-mode ruby-indent-tabs-mode)
 627   (if ruby-use-smie
 628       (smie-setup ruby-smie-grammar #'ruby-smie-rules
 629                   :forward-token  #'ruby-smie--forward-token
 630                   :backward-token #'ruby-smie--backward-token)
 631     (setq-local indent-line-function 'ruby-indent-line))
 632   (setq-local require-final-newline t)
 633   (setq-local comment-start "# ")
 634   (setq-local comment-end "")
 635   (setq-local comment-column ruby-comment-column)
 636   (setq-local comment-start-skip "#+ *")
 637   (setq-local parse-sexp-ignore-comments t)
 638   (setq-local parse-sexp-lookup-properties t)
 639   (setq-local paragraph-start (concat "$\\|" page-delimiter))
 640   (setq-local paragraph-separate paragraph-start)
 641   (setq-local paragraph-ignore-fill-prefix t))
 642
 643 (defun ruby--insert-coding-comment (encoding)
 644   "Insert a magic coding comment for ENCODING.
 645 The style of the comment is controlled by `ruby-encoding-magic-comment-style'."
 646   (let ((encoding-magic-comment-template
 647          (pcase ruby-encoding-magic-comment-style
 648            (`ruby "# coding: %s")
 649            (`emacs "# -*- coding: %s -*-")
 650            (`custom
 651             ruby-custom-encoding-magic-comment-template))))
 652     (insert
 653      (format encoding-magic-comment-template encoding)
 654      "\n")))
 655
 656 (defun ruby--detect-encoding ()
 657   (if (eq ruby-insert-encoding-magic-comment 'always-utf8)
 658       "utf-8"
 659     (let ((coding-system
 660            (or save-buffer-coding-system
 661                buffer-file-coding-system)))
 662       (if coding-system
 663           (setq coding-system
 664                 (or (coding-system-get coding-system 'mime-charset)
 665                     (coding-system-change-eol-conversion coding-system nil))))
 666       (if coding-system
 667           (symbol-name
 668            (if ruby-use-encoding-map
 669                (let ((elt (assq coding-system ruby-encoding-map)))
 670                  (if elt (cdr elt) coding-system))
 671              coding-system))
 672         "ascii-8bit"))))
 673
 674 (defun ruby--encoding-comment-required-p ()
 675   (or (eq ruby-insert-encoding-magic-comment 'always-utf8)
 676       (re-search-forward "[^\0-\177]" nil t)))
 677
 678 (defun ruby-mode-set-encoding ()
 679   "Insert a magic comment header with the proper encoding if necessary."
 680   (save-excursion
 681     (widen)
 682     (goto-char (point-min))
 683     (when (ruby--encoding-comment-required-p)
 684       (goto-char (point-min))
 685       (let ((coding-system (ruby--detect-encoding)))
 686         (when coding-system
 687           (if (looking-at "^#!") (beginning-of-line 2))
 688           (cond ((looking-at "\\s *#\\s *.*\\(en\\)?coding\\s *:\\s *\\([-a-z0-9_]*\\)")
 689                  ;; update existing encoding comment if necessary
 690                  (unless (string= (match-string 2) coding-system)
 691                    (goto-char (match-beginning 2))
 692                    (delete-region (point) (match-end 2))
 693                    (insert coding-system)))
 694                 ((looking-at "\\s *#.*coding\\s *[:=]"))
 695                 (t (when ruby-insert-encoding-magic-comment
 696                      (ruby--insert-coding-comment coding-system))))
 697           (when (buffer-modified-p)
 698             (basic-save-buffer-1)))))))
 699
 700 (defun ruby-current-indentation ()
 701   "Return the indentation level of current line."
 702   (save-excursion
 703     (beginning-of-line)
 704     (back-to-indentation)
 705     (current-column)))
 706
 707 (defun ruby-indent-line (&optional ignored)
 708   "Correct the indentation of the current Ruby line."
 709   (interactive)
 710   (ruby-indent-to (ruby-calculate-indent)))
 711
 712 (defun ruby-indent-to (column)
 713   "Indent the current line to COLUMN."
 714   (when column
 715     (let (shift top beg)
 716       (and (< column 0) (error "Invalid nesting"))
 717       (setq shift (current-column))
 718       (beginning-of-line)
 719       (setq beg (point))
 720       (back-to-indentation)
 721       (setq top (current-column))
 722       (skip-chars-backward " \t")
 723       (if (>= shift top) (setq shift (- shift top))
 724         (setq shift 0))
 725       (if (and (bolp)
 726                (= column top))
 727           (move-to-column (+ column shift))
 728         (move-to-column top)
 729         (delete-region beg (point))
 730         (beginning-of-line)
 731         (indent-to column)
 732         (move-to-column (+ column shift))))))
 733
 734 (defun ruby-special-char-p (&optional pos)
 735   "Return t if the character before POS is a special character.
 736 If omitted, POS defaults to the current point.
 737 Special characters are `?', `$', `:' when preceded by whitespace,
 738 and `\\' when preceded by `?'."
 739   (setq pos (or pos (point)))
 740   (let ((c (char-before pos)) (b (and (< (point-min) pos)
 741                                       (char-before (1- pos)))))
 742     (cond ((or (eq c ??) (eq c ?$)))
 743           ((and (eq c ?:) (or (not b) (eq (char-syntax b) ? ))))
 744           ((eq c ?\\) (eq b ??)))))
 745
 746 (defun ruby-singleton-class-p (&optional pos)
 747   (save-excursion
 748     (when pos (goto-char pos))
 749     (forward-word -1)
 750     (and (or (bolp) (not (eq (char-before (point)) ?_)))
 751          (looking-at ruby-singleton-class-re))))
 752
 753 (defun ruby-expr-beg (&optional option)
 754   "Check if point is possibly at the beginning of an expression.
 755 OPTION specifies the type of the expression.
 756 Can be one of `heredoc', `modifier', `expr-qstr', `expr-re'."
 757   (save-excursion
 758     (store-match-data nil)
 759     (let ((space (skip-chars-backward " \t"))
 760           (start (point)))
 761       (cond
 762        ((bolp) t)
 763        ((progn
 764           (forward-char -1)
 765           (and (looking-at "\\?")
 766                (or (eq (char-syntax (char-before (point))) ?w)
 767                    (ruby-special-char-p))))
 768         nil)
 769        ((looking-at ruby-operator-re))
 770        ((eq option 'heredoc)
 771         (and (< space 0) (not (ruby-singleton-class-p start))))
 772        ((or (looking-at "[\\[({,;]")
 773             (and (looking-at "[!?]")
 774                  (or (not (eq option 'modifier))
 775                      (bolp)
 776                      (save-excursion (forward-char -1) (looking-at "\\Sw$"))))
 777             (and (looking-at ruby-symbol-re)
 778                  (skip-chars-backward ruby-symbol-chars)
 779                  (cond
 780                   ((looking-at (regexp-opt
 781                                 (append ruby-block-beg-keywords
 782                                         ruby-block-op-keywords
 783                                         ruby-block-mid-keywords)
 784                                 'words))
 785                    (goto-char (match-end 0))
 786                    (not (looking-at "\\s_\\|!")))
 787                   ((eq option 'expr-qstr)
 788                    (looking-at "[a-zA-Z][a-zA-z0-9_]* +%[^ \t]"))
 789                   ((eq option 'expr-re)
 790                    (looking-at "[a-zA-Z][a-zA-z0-9_]* +/[^ \t]"))
 791                   (t nil)))))))))
 792
 793 (defun ruby-forward-string (term &optional end no-error expand)
 794   "TODO: document."
 795   (let ((n 1) (c (string-to-char term))
 796         (re (if expand
 797                 (concat "[^\\]\\(\\\\\\\\\\)*\\([" term "]\\|\\(#{\\)\\)")
 798               (concat "[^\\]\\(\\\\\\\\\\)*[" term "]"))))
 799     (while (and (re-search-forward re end no-error)
 800                 (if (match-beginning 3)
 801                     (ruby-forward-string "}{" end no-error nil)
 802                   (> (setq n (if (eq (char-before (point)) c)
 803                                      (1- n) (1+ n))) 0)))
 804       (forward-char -1))
 805     (cond ((zerop n))
 806           (no-error nil)
 807           ((error "Unterminated string")))))
 808
 809 (defun ruby-deep-indent-paren-p (c)
 810   "TODO: document."
 811   (cond ((listp ruby-deep-indent-paren)
 812          (let ((deep (assoc c ruby-deep-indent-paren)))
 813            (cond (deep
 814                   (or (cdr deep) ruby-deep-indent-paren-style))
 815                  ((memq c ruby-deep-indent-paren)
 816                   ruby-deep-indent-paren-style))))
 817         ((eq c ruby-deep-indent-paren) ruby-deep-indent-paren-style)
 818         ((eq c ?\( ) ruby-deep-arglist)))
 819
 820 (defun ruby-parse-partial (&optional end in-string nest depth pcol indent)
 821   "TODO: document throughout function body."
 822   (or depth (setq depth 0))
 823   (or indent (setq indent 0))
 824   (when (re-search-forward ruby-delimiter end 'move)
 825     (let ((pnt (point)) w re expand)
 826       (goto-char (match-beginning 0))
 827       (cond
 828        ((and (memq (char-before) '(?@ ?$)) (looking-at "\\sw"))
 829         (goto-char pnt))
 830        ((looking-at "[\"`]")            ;skip string
 831         (cond
 832          ((and (not (eobp))
 833                (ruby-forward-string (buffer-substring (point) (1+ (point)))
 834                                     end t t))
 835           nil)
 836          (t
 837           (setq in-string (point))
 838           (goto-char end))))
 839        ((looking-at "'")
 840         (cond
 841          ((and (not (eobp))
 842                (re-search-forward "[^\\]\\(\\\\\\\\\\)*'" end t))
 843           nil)
 844          (t
 845           (setq in-string (point))
 846           (goto-char end))))
 847        ((looking-at "/=")
 848         (goto-char pnt))
 849        ((looking-at "/")
 850         (cond
 851          ((and (not (eobp)) (ruby-expr-beg 'expr-re))
 852           (if (ruby-forward-string "/" end t t)
 853               nil
 854             (setq in-string (point))
 855             (goto-char end)))
 856          (t
 857           (goto-char pnt))))
 858        ((looking-at "%")
 859         (cond
 860          ((and (not (eobp))
 861                (ruby-expr-beg 'expr-qstr)
 862                (not (looking-at "%="))
 863                (looking-at "%[QqrxWw]?\\([^a-zA-Z0-9 \t\n]\\)"))
 864           (goto-char (match-beginning 1))
 865           (setq expand (not (memq (char-before) '(?q ?w))))
 866           (setq w (match-string 1))
 867           (cond
 868            ((string= w "[") (setq re "]["))
 869            ((string= w "{") (setq re "}{"))
 870            ((string= w "(") (setq re ")("))
 871            ((string= w "<") (setq re "><"))
 872            ((and expand (string= w "\\"))
 873             (setq w (concat "\\" w))))
 874           (unless (cond (re (ruby-forward-string re end t expand))
 875                         (expand (ruby-forward-string w end t t))
 876                         (t (re-search-forward
 877                             (if (string= w "\\")
 878                                 "\\\\[^\\]*\\\\"
 879                               (concat "[^\\]\\(\\\\\\\\\\)*" w))
 880                             end t)))
 881             (setq in-string (point))
 882             (goto-char end)))
 883          (t
 884           (goto-char pnt))))
 885        ((looking-at "\\?")              ;skip ?char
 886         (cond
 887          ((and (ruby-expr-beg)
 888                (looking-at "?\\(\\\\C-\\|\\\\M-\\)*\\\\?."))
 889           (goto-char (match-end 0)))
 890          (t
 891           (goto-char pnt))))
 892        ((looking-at "\\$")              ;skip $char
 893         (goto-char pnt)
 894         (forward-char 1))
 895        ((looking-at "#")                ;skip comment
 896         (forward-line 1)
 897         (goto-char (point))
 898         )
 899        ((looking-at "[\\[{(]")
 900         (let ((deep (ruby-deep-indent-paren-p (char-after))))
 901           (if (and deep (or (not (eq (char-after) ?\{)) (ruby-expr-beg)))
 902               (progn
 903                 (and (eq deep 'space) (looking-at ".\\s +[^# \t\n]")
 904                      (setq pnt (1- (match-end 0))))
 905                 (setq nest (cons (cons (char-after (point)) pnt) nest))
 906                 (setq pcol (cons (cons pnt depth) pcol))
 907                 (setq depth 0))
 908             (setq nest (cons (cons (char-after (point)) pnt) nest))
 909             (setq depth (1+ depth))))
 910         (goto-char pnt)
 911         )
 912        ((looking-at "[])}]")
 913         (if (ruby-deep-indent-paren-p (matching-paren (char-after)))
 914             (setq depth (cdr (car pcol)) pcol (cdr pcol))
 915           (setq depth (1- depth)))
 916         (setq nest (cdr nest))
 917         (goto-char pnt))
 918        ((looking-at ruby-block-end-re)
 919         (if (or (and (not (bolp))
 920                      (progn
 921                        (forward-char -1)
 922                        (setq w (char-after (point)))
 923                        (or (eq ?_ w)
 924                            (eq ?. w))))
 925                 (progn
 926                   (goto-char pnt)
 927                   (setq w (char-after (point)))
 928                   (or (eq ?_ w)
 929                       (eq ?! w)
 930                       (eq ?? w))))
 931             nil
 932           (setq nest (cdr nest))
 933           (setq depth (1- depth)))
 934         (goto-char pnt))
 935        ((looking-at "def\\s +[^(\n;]*")
 936         (if (or (bolp)
 937                 (progn
 938                   (forward-char -1)
 939                   (not (eq ?_ (char-after (point))))))
 940             (progn
 941               (setq nest (cons (cons nil pnt) nest))
 942               (setq depth (1+ depth))))
 943         (goto-char (match-end 0)))
 944        ((looking-at (concat "\\_<\\(" ruby-block-beg-re "\\)\\_>"))
 945         (and
 946          (save-match-data
 947            (or (not (looking-at "do\\_>"))
 948                (save-excursion
 949                  (back-to-indentation)
 950                  (not (looking-at ruby-non-block-do-re)))))
 951          (or (bolp)
 952              (progn
 953                (forward-char -1)
 954                (setq w (char-after (point)))
 955                (not (or (eq ?_ w)
 956                         (eq ?. w)))))
 957          (goto-char pnt)
 958          (not (eq ?! (char-after (point))))
 959          (skip-chars-forward " \t")
 960          (goto-char (match-beginning 0))
 961          (or (not (looking-at ruby-modifier-re))
 962              (ruby-expr-beg 'modifier))
 963          (goto-char pnt)
 964          (setq nest (cons (cons nil pnt) nest))
 965          (setq depth (1+ depth)))
 966         (goto-char pnt))
 967        ((looking-at ":\\(['\"]\\)")
 968         (goto-char (match-beginning 1))
 969         (ruby-forward-string (match-string 1) end t))
 970        ((looking-at ":\\([-,.+*/%&|^~<>]=?\\|===?\\|<=>\\|![~=]?\\)")
 971         (goto-char (match-end 0)))
 972        ((looking-at ":\\([a-zA-Z_][a-zA-Z_0-9]*[!?=]?\\)?")
 973         (goto-char (match-end 0)))
 974        ((or (looking-at "\\.\\.\\.?")
 975             (looking-at "\\.[0-9]+")
 976             (looking-at "\\.[a-zA-Z_0-9]+")
 977             (looking-at "\\."))
 978         (goto-char (match-end 0)))
 979        ((looking-at "^=begin")
 980         (if (re-search-forward "^=end" end t)
 981             (forward-line 1)
 982           (setq in-string (match-end 0))
 983           (goto-char end)))
 984        ((looking-at "<<")
 985         (cond
 986          ((and (ruby-expr-beg 'heredoc)
 987                (looking-at "<<\\(-\\)?\\(\\([\"'`]\\)\\([^\n]+?\\)\\3\\|\\(?:\\sw\\|\\s_\\)+\\)"))
 988           (setq re (regexp-quote (or (match-string 4) (match-string 2))))
 989           (if (match-beginning 1) (setq re (concat "\\s *" re)))
 990           (let* ((id-end (goto-char (match-end 0)))
 991                  (line-end-position (point-at-eol))
 992                  (state (list in-string nest depth pcol indent)))
 993             ;; parse the rest of the line
 994             (while (and (> line-end-position (point))
 995                         (setq state (apply 'ruby-parse-partial
 996                                            line-end-position state))))
 997             (setq in-string (car state)
 998                   nest (nth 1 state)
 999                   depth (nth 2 state)
1000                   pcol (nth 3 state)
1001                   indent (nth 4 state))
1002             ;; skip heredoc section
1003             (if (re-search-forward (concat "^" re "$") end 'move)
1004                 (forward-line 1)
1005               (setq in-string id-end)
1006               (goto-char end))))
1007          (t
1008           (goto-char pnt))))
1009        ((looking-at "^__END__$")
1010         (goto-char pnt))
1011        ((and (looking-at ruby-here-doc-beg-re)
1012              (boundp 'ruby-indent-point))
1013         (if (re-search-forward (ruby-here-doc-end-match)
1014                                ruby-indent-point t)
1015             (forward-line 1)
1016           (setq in-string (match-end 0))
1017           (goto-char ruby-indent-point)))
1018        (t
1019         (error (format "Bad string %s"
1020                        (buffer-substring (point) pnt)
1021                        ))))))
1022   (list in-string nest depth pcol))
1023
1024 (defun ruby-parse-region (start end)
1025   "TODO: document."
1026   (let (state)
1027     (save-excursion
1028       (if start
1029           (goto-char start)
1030         (ruby-beginning-of-indent))
1031       (save-restriction
1032         (narrow-to-region (point) end)
1033         (while (and (> end (point))
1034                     (setq state (apply 'ruby-parse-partial end state))))))
1035     (list (nth 0 state)                 ; in-string
1036           (car (nth 1 state))           ; nest
1037           (nth 2 state)                 ; depth
1038           (car (car (nth 3 state)))     ; pcol
1039           ;(car (nth 5 state))          ; indent
1040           )))
1041
1042 (defun ruby-indent-size (pos nest)
1043   "Return the indentation level in spaces NEST levels deeper than POS."
1044   (+ pos (* (or nest 1) ruby-indent-level)))
1045
1046 (defun ruby-calculate-indent (&optional parse-start)
1047   "Return the proper indentation level of the current line."
1048   ;; TODO: Document body
1049   (save-excursion
1050     (beginning-of-line)
1051     (let ((ruby-indent-point (point))
1052           (case-fold-search nil)
1053           state eol begin op-end
1054           (paren (progn (skip-syntax-forward " ")
1055                         (and (char-after) (matching-paren (char-after)))))
1056           (indent 0))
1057       (if parse-start
1058           (goto-char parse-start)
1059         (ruby-beginning-of-indent)
1060         (setq parse-start (point)))
1061       (back-to-indentation)
1062       (setq indent (current-column))
1063       (setq state (ruby-parse-region parse-start ruby-indent-point))
1064       (cond
1065        ((nth 0 state)                   ; within string
1066         (setq indent nil))              ;  do nothing
1067        ((car (nth 1 state))             ; in paren
1068         (goto-char (setq begin (cdr (nth 1 state))))
1069         (let ((deep (ruby-deep-indent-paren-p (car (nth 1 state)))))
1070           (if deep
1071               (cond ((and (eq deep t) (eq (car (nth 1 state)) paren))
1072                      (skip-syntax-backward " ")
1073                      (setq indent (1- (current-column))))
1074                     ((let ((s (ruby-parse-region (point) ruby-indent-point)))
1075                        (and (nth 2 s) (> (nth 2 s) 0)
1076                             (or (goto-char (cdr (nth 1 s))) t)))
1077                      (forward-word -1)
1078                      (setq indent (ruby-indent-size (current-column)
1079                                                     (nth 2 state))))
1080                     (t
1081                      (setq indent (current-column))
1082                      (cond ((eq deep 'space))
1083                            (paren (setq indent (1- indent)))
1084                            (t (setq indent (ruby-indent-size (1- indent) 1))))))
1085             (if (nth 3 state) (goto-char (nth 3 state))
1086               (goto-char parse-start) (back-to-indentation))
1087             (setq indent (ruby-indent-size (current-column) (nth 2 state))))
1088           (and (eq (car (nth 1 state)) paren)
1089                (ruby-deep-indent-paren-p (matching-paren paren))
1090                (search-backward (char-to-string paren))
1091                (setq indent (current-column)))))
1092        ((and (nth 2 state) (> (nth 2 state) 0)) ; in nest
1093         (if (null (cdr (nth 1 state)))
1094             (error "Invalid nesting"))
1095         (goto-char (cdr (nth 1 state)))
1096         (forward-word -1)               ; skip back a keyword
1097         (setq begin (point))
1098         (cond
1099          ((looking-at "do\\>[^_]")      ; iter block is a special case
1100           (if (nth 3 state) (goto-char (nth 3 state))
1101             (goto-char parse-start) (back-to-indentation))
1102           (setq indent (ruby-indent-size (current-column) (nth 2 state))))
1103          (t
1104           (setq indent (+ (current-column) ruby-indent-level)))))
1105
1106        ((and (nth 2 state) (< (nth 2 state) 0)) ; in negative nest
1107         (setq indent (ruby-indent-size (current-column) (nth 2 state)))))
1108       (when indent
1109         (goto-char ruby-indent-point)
1110         (end-of-line)
1111         (setq eol (point))
1112         (beginning-of-line)
1113         (cond
1114          ((and (not (ruby-deep-indent-paren-p paren))
1115                (re-search-forward ruby-negative eol t))
1116           (and (not (eq ?_ (char-after (match-end 0))))
1117                (setq indent (- indent ruby-indent-level))))
1118          ((and
1119            (save-excursion
1120              (beginning-of-line)
1121              (not (bobp)))
1122            (or (ruby-deep-indent-paren-p t)
1123                (null (car (nth 1 state)))))
1124           ;; goto beginning of non-empty no-comment line
1125           (let (end done)
1126             (while (not done)
1127               (skip-chars-backward " \t\n")
1128               (setq end (point))
1129               (beginning-of-line)
1130               (if (re-search-forward "^\\s *#" end t)
1131                   (beginning-of-line)
1132                 (setq done t))))
1133           (end-of-line)
1134           ;; skip the comment at the end
1135           (skip-chars-backward " \t")
1136           (let (end (pos (point)))
1137             (beginning-of-line)
1138             (while (and (re-search-forward "#" pos t)
1139                         (setq end (1- (point)))
1140                         (or (ruby-special-char-p end)
1141                             (and (setq state (ruby-parse-region
1142                                               parse-start end))
1143                                  (nth 0 state))))
1144               (setq end nil))
1145             (goto-char (or end pos))
1146             (skip-chars-backward " \t")
1147             (setq begin (if (and end (nth 0 state)) pos (cdr (nth 1 state))))
1148             (setq state (ruby-parse-region parse-start (point))))
1149           (or (bobp) (forward-char -1))
1150           (and
1151            (or (and (looking-at ruby-symbol-re)
1152                     (skip-chars-backward ruby-symbol-chars)
1153                     (looking-at (concat "\\<\\(" ruby-block-hanging-re
1154                                         "\\)\\>"))
1155                     (not (eq (point) (nth 3 state)))
1156                     (save-excursion
1157                       (goto-char (match-end 0))
1158                       (not (looking-at "[a-z_]"))))
1159                (and (looking-at ruby-operator-re)
1160                     (not (ruby-special-char-p))
1161                     (save-excursion
1162                       (forward-char -1)
1163                       (or (not (looking-at ruby-operator-re))
1164                           (not (eq (char-before) ?:))))
1165                     ;; Operator at the end of line.
1166                     (let ((c (char-after (point))))
1167                       (and
1168 ;;                     (or (null begin)
1169 ;;                         (save-excursion
1170 ;;                           (goto-char begin)
1171 ;;                           (skip-chars-forward " \t")
1172 ;;                           (not (or (eolp) (looking-at "#")
1173 ;;                                    (and (eq (car (nth 1 state)) ?{)
1174 ;;                                         (looking-at "|"))))))
1175                        ;; Not a regexp or percent literal.
1176                        (null (nth 0 (ruby-parse-region (or begin parse-start)
1177                                                        (point))))
1178                        (or (not (eq ?| (char-after (point))))
1179                            (save-excursion
1180                              (or (eolp) (forward-char -1))
1181                              (cond
1182                               ((search-backward "|" nil t)
1183                                (skip-chars-backward " \t\n")
1184                                (and (not (eolp))
1185                                     (progn
1186                                       (forward-char -1)
1187                                       (not (looking-at "{")))
1188                                     (progn
1189                                       (forward-word -1)
1190                                       (not (looking-at "do\\>[^_]")))))
1191                               (t t))))
1192                        (not (eq ?, c))
1193                        (setq op-end t)))))
1194            (setq indent
1195                  (cond
1196                   ((and
1197                     (null op-end)
1198                     (not (looking-at (concat "\\<\\(" ruby-block-hanging-re
1199                                              "\\)\\>")))
1200                     (eq (ruby-deep-indent-paren-p t) 'space)
1201                     (not (bobp)))
1202                    (widen)
1203                    (goto-char (or begin parse-start))
1204                    (skip-syntax-forward " ")
1205                    (current-column))
1206                   ((car (nth 1 state)) indent)
1207                   (t
1208                    (+ indent ruby-indent-level))))))))
1209       (goto-char ruby-indent-point)
1210       (beginning-of-line)
1211       (skip-syntax-forward " ")
1212       (if (looking-at "\\.[^.]")
1213           (+ indent ruby-indent-level)
1214         indent))))
1215
1216 (defun ruby-beginning-of-defun (&optional arg)
1217   "Move backward to the beginning of the current defun.
1218 With ARG, move backward multiple defuns.  Negative ARG means
1219 move forward."
1220   (interactive "p")
1221   (let (case-fold-search)
1222     (and (re-search-backward (concat "^\\s *" ruby-defun-beg-re "\\_>")
1223                              nil t (or arg 1))
1224          (beginning-of-line))))
1225
1226 (defun ruby-end-of-defun ()
1227   "Move point to the end of the current defun.
1228 The defun begins at or after the point.  This function is called
1229 by `end-of-defun'."
1230   (interactive "p")
1231   (ruby-forward-sexp)
1232   (let (case-fold-search)
1233     (when (looking-back (concat "^\\s *" ruby-block-end-re))
1234       (forward-line 1))))
1235
1236 (defun ruby-beginning-of-indent ()
1237   "Backtrack to a line which can be used as a reference for
1238 calculating indentation on the lines after it."
1239   (while (and (re-search-backward ruby-indent-beg-re nil 'move)
1240               (if (ruby-in-ppss-context-p 'anything)
1241                   t
1242                 ;; We can stop, then.
1243                 (beginning-of-line)))))
1244
1245 (defun ruby-move-to-block (n)
1246   "Move to the beginning (N < 0) or the end (N > 0) of the
1247 current block, a sibling block, or an outer block.  Do that (abs N) times."
1248   (back-to-indentation)
1249   (let ((signum (if (> n 0) 1 -1))
1250         (backward (< n 0))
1251         (depth (or (nth 2 (ruby-parse-region (point) (line-end-position))) 0))
1252         case-fold-search
1253         down done)
1254     (when (looking-at ruby-block-mid-re)
1255       (setq depth (+ depth signum)))
1256     (when (< (* depth signum) 0)
1257       ;; Moving end -> end or beginning -> beginning.
1258       (setq depth 0))
1259     (dotimes (_ (abs n))
1260       (setq done nil)
1261       (setq down (save-excursion
1262                    (back-to-indentation)
1263                    ;; There is a block start or block end keyword on this
1264                    ;; line, don't need to look for another block.
1265                    (and (re-search-forward
1266                          (if backward ruby-block-end-re
1267                            (concat "\\_<\\(" ruby-block-beg-re "\\)\\_>"))
1268                          (line-end-position) t)
1269                         (not (nth 8 (syntax-ppss))))))
1270       (while (and (not done) (not (if backward (bobp) (eobp))))
1271         (forward-line signum)
1272         (cond
1273          ;; Skip empty and commented out lines.
1274          ((looking-at "^\\s *$"))
1275          ((looking-at "^\\s *#"))
1276          ;; Skip block comments;
1277          ((and (not backward) (looking-at "^=begin\\>"))
1278           (re-search-forward "^=end\\>"))
1279          ((and backward (looking-at "^=end\\>"))
1280           (re-search-backward "^=begin\\>"))
1281          ;; Jump over a multiline literal.
1282          ((ruby-in-ppss-context-p 'string)
1283           (goto-char (nth 8 (syntax-ppss)))
1284           (unless backward
1285             (forward-sexp)
1286             (when (bolp) (forward-char -1)))) ; After a heredoc.
1287          (t
1288           (let ((state (ruby-parse-region (point) (line-end-position))))
1289             (unless (car state) ; Line ends with unfinished string.
1290               (setq depth (+ (nth 2 state) depth))))
1291           (cond
1292            ;; Increased depth, we found a block.
1293            ((> (* signum depth) 0)
1294             (setq down t))
1295            ;; We're at the same depth as when we started, and we've
1296            ;; encountered a block before.  Stop.
1297            ((and down (zerop depth))
1298             (setq done t))
1299            ;; Lower depth, means outer block, can stop now.
1300            ((< (* signum depth) 0)
1301             (setq done t)))))))
1302     (back-to-indentation)))
1303
1304 (defun ruby-beginning-of-block (&optional arg)
1305   "Move backward to the beginning of the current block.
1306 With ARG, move up multiple blocks."
1307   (interactive "p")
1308   (ruby-move-to-block (- (or arg 1))))
1309
1310 (defun ruby-end-of-block (&optional arg)
1311   "Move forward to the end of the current block.
1312 With ARG, move out of multiple blocks."
1313   (interactive "p")
1314   (ruby-move-to-block (or arg 1)))
1315
1316 (defun ruby-forward-sexp (&optional arg)
1317   "Move forward across one balanced expression (sexp).
1318 With ARG, do it many times.  Negative ARG means move backward."
1319   ;; TODO: Document body
1320   (interactive "p")
1321   (cond
1322    (ruby-use-smie (forward-sexp arg))
1323    ((and (numberp arg) (< arg 0)) (ruby-backward-sexp (- arg)))
1324    (t
1325     (let ((i (or arg 1)))
1326       (condition-case nil
1327           (while (> i 0)
1328             (skip-syntax-forward " ")
1329             (if (looking-at ",\\s *") (goto-char (match-end 0)))
1330             (cond ((looking-at "\\?\\(\\\\[CM]-\\)*\\\\?\\S ")
1331                    (goto-char (match-end 0)))
1332                   ((progn
1333                      (skip-chars-forward ",.:;|&^~=!?\\+\\-\\*")
1334                      (looking-at "\\s("))
1335                    (goto-char (scan-sexps (point) 1)))
1336                   ((and (looking-at (concat "\\<\\(" ruby-block-beg-re
1337                                             "\\)\\>"))
1338                         (not (eq (char-before (point)) ?.))
1339                         (not (eq (char-before (point)) ?:)))
1340                    (ruby-end-of-block)
1341                    (forward-word 1))
1342                   ((looking-at "\\(\\$\\|@@?\\)?\\sw")
1343                    (while (progn
1344                             (while (progn (forward-word 1) (looking-at "_")))
1345                             (cond ((looking-at "::") (forward-char 2) t)
1346                                   ((> (skip-chars-forward ".") 0))
1347                                   ((looking-at "\\?\\|!\\(=[~=>]\\|[^~=]\\)")
1348                                    (forward-char 1) nil)))))
1349                   ((let (state expr)
1350                      (while
1351                          (progn
1352                            (setq expr (or expr (ruby-expr-beg)
1353                                           (looking-at "%\\sw?\\Sw\\|[\"'`/]")))
1354                            (nth 1 (setq state (apply #'ruby-parse-partial
1355                                                      nil state))))
1356                        (setq expr t)
1357                        (skip-chars-forward "<"))
1358                      (not expr))))
1359             (setq i (1- i)))
1360         ((error) (forward-word 1)))
1361       i))))
1362
1363 (defun ruby-backward-sexp (&optional arg)
1364   "Move backward across one balanced expression (sexp).
1365 With ARG, do it many times.  Negative ARG means move forward."
1366   ;; TODO: Document body
1367   (interactive "p")
1368   (cond
1369    (ruby-use-smie (backward-sexp arg))
1370    ((and (numberp arg) (< arg 0)) (ruby-forward-sexp (- arg)))
1371    (t
1372     (let ((i (or arg 1)))
1373       (condition-case nil
1374           (while (> i 0)
1375             (skip-chars-backward " \t\n,.:;|&^~=!?\\+\\-\\*")
1376             (forward-char -1)
1377             (cond ((looking-at "\\s)")
1378                    (goto-char (scan-sexps (1+ (point)) -1))
1379                    (pcase (char-before)
1380                      (`?% (forward-char -1))
1381                      ((or `?q `?Q `?w `?W `?r `?x)
1382                       (if (eq (char-before (1- (point))) ?%)
1383                           (forward-char -2))))
1384                    nil)
1385                   ((looking-at "\\s\"\\|\\\\\\S_")
1386                    (let ((c (char-to-string (char-before (match-end 0)))))
1387                      (while (and (search-backward c)
1388                                  (eq (logand (skip-chars-backward "\\") 1)
1389                                      1))))
1390                    nil)
1391                   ((looking-at "\\s.\\|\\s\\")
1392                    (if (ruby-special-char-p) (forward-char -1)))
1393                   ((looking-at "\\s(") nil)
1394                   (t
1395                    (forward-char 1)
1396                    (while (progn (forward-word -1)
1397                                  (pcase (char-before)
1398                                    (`?_ t)
1399                                    (`?. (forward-char -1) t)
1400                                    ((or `?$ `?@)
1401                                     (forward-char -1)
1402                                     (and (eq (char-before) (char-after))
1403                                          (forward-char -1)))
1404                                    (`?:
1405                                     (forward-char -1)
1406                                     (eq (char-before) :)))))
1407                    (if (looking-at ruby-block-end-re)
1408                        (ruby-beginning-of-block))
1409                    nil))
1410             (setq i (1- i)))
1411         ((error)))
1412       i))))
1413
1414 (defun ruby-indent-exp (&optional ignored)
1415   "Indent each line in the balanced expression following the point."
1416   (interactive "*P")
1417   (let ((here (point-marker)) start top column (nest t))
1418     (set-marker-insertion-type here t)
1419     (unwind-protect
1420         (progn
1421           (beginning-of-line)
1422           (setq start (point) top (current-indentation))
1423           (while (and (not (eobp))
1424                       (progn
1425                         (setq column (ruby-calculate-indent start))
1426                         (cond ((> column top)
1427                                (setq nest t))
1428                               ((and (= column top) nest)
1429                                (setq nest nil) t))))
1430             (ruby-indent-to column)
1431             (beginning-of-line 2)))
1432       (goto-char here)
1433       (set-marker here nil))))
1434
1435 (defun ruby-add-log-current-method ()
1436   "Return the current method name as a string.
1437 This string includes all namespaces.
1438
1439 For example:
1440
1441   #exit
1442   String#gsub
1443   Net::HTTP#active?
1444   File.open
1445
1446 See `add-log-current-defun-function'."
1447   (condition-case nil
1448       (save-excursion
1449         (let* ((indent 0) mname mlist
1450                (start (point))
1451                (make-definition-re
1452                 (lambda (re)
1453                   (concat "^[ \t]*" re "[ \t]+"
1454                           "\\("
1455                           ;; \\. and :: for class methods
1456                           "\\([A-Za-z_]" ruby-symbol-re "*\\|\\.\\|::" "\\)"
1457                           "+\\)")))
1458                (definition-re (funcall make-definition-re ruby-defun-beg-re))
1459                (module-re (funcall make-definition-re "\\(class\\|module\\)")))
1460           ;; Get the current method definition (or class/module).
1461           (when (re-search-backward definition-re nil t)
1462             (goto-char (match-beginning 1))
1463             (if (not (string-equal "def" (match-string 1)))
1464                 (setq mlist (list (match-string 2)))
1465               ;; We're inside the method. For classes and modules,
1466               ;; this check is skipped for performance.
1467               (when (ruby-block-contains-point start)
1468                 (setq mname (match-string 2))))
1469             (setq indent (current-column))
1470             (beginning-of-line))
1471           ;; Walk up the class/module nesting.
1472           (while (and (> indent 0)
1473                       (re-search-backward module-re nil t))
1474             (goto-char (match-beginning 1))
1475             (when (< (current-column) indent)
1476               (setq mlist (cons (match-string 2) mlist))
1477               (setq indent (current-column))
1478               (beginning-of-line)))
1479           ;; Process the method name.
1480           (when mname
1481             (let ((mn (split-string mname "\\.\\|::")))
1482               (if (cdr mn)
1483                   (progn
1484                     (unless (string-equal "self" (car mn)) ; def self.foo
1485                       ;; def C.foo
1486                       (let ((ml (nreverse mlist)))
1487                         ;; If the method name references one of the
1488                         ;; containing modules, drop the more nested ones.
1489                         (while ml
1490                           (if (string-equal (car ml) (car mn))
1491                               (setq mlist (nreverse (cdr ml)) ml nil))
1492                           (or (setq ml (cdr ml)) (nreverse mlist))))
1493                       (if mlist
1494                           (setcdr (last mlist) (butlast mn))
1495                         (setq mlist (butlast mn))))
1496                     (setq mname (concat "." (car (last mn)))))
1497                 ;; See if the method is in singleton class context.
1498                 (let ((in-singleton-class
1499                        (when (re-search-forward ruby-singleton-class-re start t)
1500                          (goto-char (match-beginning 0))
1501                          ;; FIXME: Optimize it out, too?
1502                          ;; This can be slow in a large file, but
1503                          ;; unlike class/module declaration
1504                          ;; indentations, method definitions can be
1505                          ;; intermixed with these, and may or may not
1506                          ;; be additionally indented after visibility
1507                          ;; keywords.
1508                          (ruby-block-contains-point start))))
1509                   (setq mname (concat
1510                                (if in-singleton-class "." "#")
1511                                mname))))))
1512           ;; Generate the string.
1513           (if (consp mlist)
1514               (setq mlist (mapconcat (function identity) mlist "::")))
1515           (if mname
1516               (if mlist (concat mlist mname) mname)
1517             mlist)))))
1518
1519 (defun ruby-block-contains-point (pt)
1520   (save-excursion
1521     (save-match-data
1522       (ruby-forward-sexp)
1523       (> (point) pt))))
1524
1525 (defun ruby-brace-to-do-end (orig end)
1526   (let (beg-marker end-marker)
1527     (goto-char end)
1528     (when (eq (char-before) ?\})
1529       (delete-char -1)
1530       (when (save-excursion
1531               (skip-chars-backward " \t")
1532               (not (bolp)))
1533         (insert "\n"))
1534       (insert "end")
1535       (setq end-marker (point-marker))
1536       (when (and (not (eobp)) (eq (char-syntax (char-after)) ?w))
1537         (insert " "))
1538       (goto-char orig)
1539       (delete-char 1)
1540       (when (eq (char-syntax (char-before)) ?w)
1541         (insert " "))
1542       (insert "do")
1543       (setq beg-marker (point-marker))
1544       (when (looking-at "\\(\\s \\)*|")
1545         (unless (match-beginning 1)
1546           (insert " "))
1547         (goto-char (1+ (match-end 0)))
1548         (search-forward "|"))
1549       (unless (looking-at "\\s *$")
1550         (insert "\n"))
1551       (indent-region beg-marker end-marker)
1552       (goto-char beg-marker)
1553       t)))
1554
1555 (defun ruby-do-end-to-brace (orig end)
1556   (let (beg-marker end-marker beg-pos end-pos)
1557     (goto-char (- end 3))
1558     (when (looking-at ruby-block-end-re)
1559       (delete-char 3)
1560       (setq end-marker (point-marker))
1561       (insert "}")
1562       (goto-char orig)
1563       (delete-char 2)
1564       ;; Maybe this should be customizable, let's see if anyone asks.
1565       (insert "{ ")
1566       (setq beg-marker (point-marker))
1567       (when (looking-at "\\s +|")
1568         (delete-char (- (match-end 0) (match-beginning 0) 1))
1569         (forward-char)
1570         (re-search-forward "|" (line-end-position) t))
1571       (save-excursion
1572         (skip-chars-forward " \t\n\r")
1573         (setq beg-pos (point))
1574         (goto-char end-marker)
1575         (skip-chars-backward " \t\n\r")
1576         (setq end-pos (point)))
1577       (when (or
1578              (< end-pos beg-pos)
1579              (and (= (line-number-at-pos beg-pos) (line-number-at-pos end-pos))
1580                   (< (+ (current-column) (- end-pos beg-pos) 2) fill-column)))
1581         (just-one-space -1)
1582         (goto-char end-marker)
1583         (just-one-space -1))
1584       (goto-char beg-marker)
1585       t)))
1586
1587 (defun ruby-toggle-block ()
1588   "Toggle block type from do-end to braces or back.
1589 The block must begin on the current line or above it and end after the point.
1590 If the result is do-end block, it will always be multiline."
1591   (interactive)
1592   (let ((start (point)) beg end)
1593     (end-of-line)
1594     (unless
1595         (if (and (re-search-backward "\\(?:[^#]\\)\\({\\)\\|\\(\\_<do\\_>\\)")
1596                  (progn
1597                    (goto-char (or (match-beginning 1) (match-beginning 2)))
1598                    (setq beg (point))
1599                    (save-match-data (ruby-forward-sexp))
1600                    (setq end (point))
1601                    (> end start)))
1602             (if (match-beginning 1)
1603                 (ruby-brace-to-do-end beg end)
1604               (ruby-do-end-to-brace beg end)))
1605       (goto-char start))))
1606
1607 (eval-and-compile
1608   (defconst ruby-percent-literal-beg-re
1609     "\\(%\\)[qQrswWxIi]?\\([[:punct:]]\\)"
1610     "Regexp to match the beginning of percent literal.")
1611
1612   (defconst ruby-syntax-methods-before-regexp
1613     '("gsub" "gsub!" "sub" "sub!" "scan" "split" "split!" "index" "match"
1614       "assert_match" "Given" "Then" "When")
1615     "Methods that can take regexp as the first argument.
1616 It will be properly highlighted even when the call omits parens.")
1617
1618   (defvar ruby-syntax-before-regexp-re
1619     (concat
1620      ;; Special tokens that can't be followed by a division operator.
1621      "\\(^\\|[[=(,~;<>]"
1622      ;; Distinguish ternary operator tokens.
1623      ;; FIXME: They don't really have to be separated with spaces.
1624      "\\|[?:] "
1625      ;; Control flow keywords and operators following bol or whitespace.
1626      "\\|\\(?:^\\|\\s \\)"
1627      (regexp-opt '("if" "elsif" "unless" "while" "until" "when" "and"
1628                    "or" "not" "&&" "||"))
1629      ;; Method name from the list.
1630      "\\|\\_<"
1631      (regexp-opt ruby-syntax-methods-before-regexp)
1632      "\\)\\s *")
1633     "Regexp to match text that can be followed by a regular expression."))
1634
1635 (defun ruby-syntax-propertize-function (start end)
1636   "Syntactic keywords for Ruby mode.  See `syntax-propertize-function'."
1637   (let (case-fold-search)
1638     (goto-char start)
1639     (remove-text-properties start end '(ruby-expansion-match-data))
1640     (ruby-syntax-propertize-heredoc end)
1641     (ruby-syntax-enclosing-percent-literal end)
1642     (funcall
1643      (syntax-propertize-rules
1644       ;; $' $" $` .... are variables.
1645       ;; ?' ?" ?` are character literals (one-char strings in 1.9+).
1646       ("\\([?$]\\)[#\"'`]"
1647        (1 (unless (save-excursion
1648                     ;; Not within a string.
1649                     (nth 3 (syntax-ppss (match-beginning 0))))
1650             (string-to-syntax "\\"))))
1651       ;; Regular expressions.  Start with matching unescaped slash.
1652       ("\\(?:\\=\\|[^\\]\\)\\(?:\\\\\\\\\\)*\\(/\\)"
1653        (1 (let ((state (save-excursion (syntax-ppss (match-beginning 1)))))
1654             (when (or
1655                    ;; Beginning of a regexp.
1656                    (and (null (nth 8 state))
1657                         (save-excursion
1658                           (forward-char -1)
1659                           (looking-back ruby-syntax-before-regexp-re
1660                                         (point-at-bol))))
1661                    ;; End of regexp.  We don't match the whole
1662                    ;; regexp at once because it can have
1663                    ;; string interpolation inside, or span
1664                    ;; several lines.
1665                    (eq ?/ (nth 3 state)))
1666               (string-to-syntax "\"/")))))
1667       ;; Expression expansions in strings.  We're handling them
1668       ;; here, so that the regexp rule never matches inside them.
1669       (ruby-expression-expansion-re
1670        (0 (ignore (ruby-syntax-propertize-expansion))))
1671       ("^=en\\(d\\)\\_>" (1 "!"))
1672       ("^\\(=\\)begin\\_>" (1 "!"))
1673       ;; Handle here documents.
1674       ((concat ruby-here-doc-beg-re ".*\\(\n\\)")
1675        (7 (unless (or (nth 8 (save-excursion
1676                                (syntax-ppss (match-beginning 0))))
1677                       (ruby-singleton-class-p (match-beginning 0)))
1678             (put-text-property (match-beginning 7) (match-end 7)
1679                                'syntax-table (string-to-syntax "\""))
1680             (ruby-syntax-propertize-heredoc end))))
1681       ;; Handle percent literals: %w(), %q{}, etc.
1682       ((concat "\\(?:^\\|[[ \t\n<+(,=]\\)" ruby-percent-literal-beg-re)
1683        (1 (prog1 "|" (ruby-syntax-propertize-percent-literal end)))))
1684      (point) end)))
1685
1686 (defun ruby-syntax-propertize-heredoc (limit)
1687   (let ((ppss (syntax-ppss))
1688         (res '()))
1689     (when (eq ?\n (nth 3 ppss))
1690       (save-excursion
1691         (goto-char (nth 8 ppss))
1692         (beginning-of-line)
1693         (while (re-search-forward ruby-here-doc-beg-re
1694                                   (line-end-position) t)
1695           (unless (ruby-singleton-class-p (match-beginning 0))
1696             (push (concat (ruby-here-doc-end-match) "\n") res))))
1697       (save-excursion
1698         ;; With multiple openers on the same line, we don't know in which
1699         ;; part `start' is, so we have to go back to the beginning.
1700         (when (cdr res)
1701           (goto-char (nth 8 ppss))
1702           (setq res (nreverse res)))
1703         (while (and res (re-search-forward (pop res) limit 'move))
1704           (if (null res)
1705               (put-text-property (1- (point)) (point)
1706                                  'syntax-table (string-to-syntax "\""))))
1707         ;; End up at bol following the heredoc openers.
1708         ;; Propertize expression expansions from this point forward.
1709         ))))
1710
1711 (defun ruby-syntax-enclosing-percent-literal (limit)
1712   (let ((state (syntax-ppss))
1713         (start (point)))
1714     ;; When already inside percent literal, re-propertize it.
1715     (when (eq t (nth 3 state))
1716       (goto-char (nth 8 state))
1717       (when (looking-at ruby-percent-literal-beg-re)
1718         (ruby-syntax-propertize-percent-literal limit))
1719       (when (< (point) start) (goto-char start)))))
1720
1721 (defun ruby-syntax-propertize-percent-literal (limit)
1722   (goto-char (match-beginning 2))
1723   ;; Not inside a simple string or comment.
1724   (when (eq t (nth 3 (syntax-ppss)))
1725     (let* ((op (char-after))
1726            (ops (char-to-string op))
1727            (cl (or (cdr (aref (syntax-table) op))
1728                    (cdr (assoc op '((?< . ?>))))))
1729            parse-sexp-lookup-properties)
1730       (save-excursion
1731         (condition-case nil
1732             (progn
1733               (if cl              ; Paired delimiters.
1734                   ;; Delimiter pairs of the same kind can be nested
1735                   ;; inside the literal, as long as they are balanced.
1736                   ;; Create syntax table that ignores other characters.
1737                   (with-syntax-table (make-char-table 'syntax-table nil)
1738                     (modify-syntax-entry op (concat "(" (char-to-string cl)))
1739                     (modify-syntax-entry cl (concat ")" ops))
1740                     (modify-syntax-entry ?\\ "\\")
1741                     (save-restriction
1742                       (narrow-to-region (point) limit)
1743                       (forward-list))) ; skip to the paired character
1744                 ;; Single character delimiter.
1745                 (re-search-forward (concat "[^\\]\\(?:\\\\\\\\\\)*"
1746                                            (regexp-quote ops)) limit nil))
1747               ;; Found the closing delimiter.
1748               (put-text-property (1- (point)) (point) 'syntax-table
1749                                  (string-to-syntax "|")))
1750           ;; Unclosed literal, do nothing.
1751           ((scan-error search-failed)))))))
1752
1753 (defun ruby-syntax-propertize-expansion ()
1754   ;; Save the match data to a text property, for font-locking later.
1755   ;; Set the syntax of all double quotes and backticks to punctuation.
1756   (let* ((beg (match-beginning 2))
1757          (end (match-end 2))
1758          (state (and beg (save-excursion (syntax-ppss beg)))))
1759     (when (ruby-syntax-expansion-allowed-p state)
1760       (put-text-property beg (1+ beg) 'ruby-expansion-match-data
1761                          (match-data))
1762       (goto-char beg)
1763       (while (re-search-forward "[\"`]" end 'move)
1764         (put-text-property (match-beginning 0) (match-end 0)
1765                            'syntax-table (string-to-syntax "."))))))
1766
1767 (defun ruby-syntax-expansion-allowed-p (parse-state)
1768   "Return non-nil if expression expansion is allowed."
1769   (let ((term (nth 3 parse-state)))
1770     (cond
1771      ((memq term '(?\" ?` ?\n ?/)))
1772      ((eq term t)
1773       (save-match-data
1774         (save-excursion
1775           (goto-char (nth 8 parse-state))
1776           (looking-at "%\\(?:[QWrxI]\\|\\W\\)")))))))
1777
1778 (defun ruby-syntax-propertize-expansions (start end)
1779   (save-excursion
1780     (goto-char start)
1781     (while (re-search-forward ruby-expression-expansion-re end 'move)
1782       (ruby-syntax-propertize-expansion))))
1783
1784 (defun ruby-in-ppss-context-p (context &optional ppss)
1785   (let ((ppss (or ppss (syntax-ppss (point)))))
1786     (if (cond
1787          ((eq context 'anything)
1788           (or (nth 3 ppss)
1789               (nth 4 ppss)))
1790          ((eq context 'string)
1791           (nth 3 ppss))
1792          ((eq context 'heredoc)
1793           (eq ?\n (nth 3 ppss)))
1794          ((eq context 'non-heredoc)
1795           (and (ruby-in-ppss-context-p 'anything)
1796                (not (ruby-in-ppss-context-p 'heredoc))))
1797          ((eq context 'comment)
1798           (nth 4 ppss))
1799          (t
1800           (error (concat
1801                   "Internal error on `ruby-in-ppss-context-p': "
1802                   "context name `" (symbol-name context) "' is unknown"))))
1803         t)))
1804
1805 (defvar ruby-font-lock-syntax-table
1806   (let ((tbl (copy-syntax-table ruby-mode-syntax-table)))
1807     (modify-syntax-entry ?_ "w" tbl)
1808     tbl)
1809   "The syntax table to use for fontifying Ruby mode buffers.
1810 See `font-lock-syntax-table'.")
1811
1812 (defconst ruby-font-lock-keyword-beg-re "\\(?:^\\|[^.@$]\\|\\.\\.\\)")
1813
1814 (defconst ruby-font-lock-keywords
1815   `(;; Functions.
1816     ("^\\s *def\\s +\\(?:[^( \t\n.]*\\.\\)?\\([^( \t\n]+\\)"
1817      1 font-lock-function-name-face)
1818     ;; Keywords.
1819     (,(concat
1820        ruby-font-lock-keyword-beg-re
1821        (regexp-opt
1822         '("alias"
1823           "and"
1824           "begin"
1825           "break"
1826           "case"
1827           "class"
1828           "def"
1829           "defined?"
1830           "do"
1831           "elsif"
1832           "else"
1833           "fail"
1834           "ensure"
1835           "for"
1836           "end"
1837           "if"
1838           "in"
1839           "module"
1840           "next"
1841           "not"
1842           "or"
1843           "redo"
1844           "rescue"
1845           "retry"
1846           "return"
1847           "then"
1848           "super"
1849           "unless"
1850           "undef"
1851           "until"
1852           "when"
1853           "while"
1854           "yield")
1855         'symbols))
1856      (1 font-lock-keyword-face))
1857     ;; Some core methods.
1858     (,(concat
1859        ruby-font-lock-keyword-beg-re
1860        (regexp-opt
1861         '( ;; built-in methods on Kernel
1862           "__callee__"
1863           "__dir__"
1864           "__method__"
1865           "abort"
1866           "at_exit"
1867           "autoload"
1868           "autoload?"
1869           "binding"
1870           "block_given?"
1871           "caller"
1872           "catch"
1873           "eval"
1874           "exec"
1875           "exit"
1876           "exit!"
1877           "fail"
1878           "fork"
1879           "format"
1880           "lambda"
1881           "load"
1882           "loop"
1883           "open"
1884           "p"
1885           "print"
1886           "printf"
1887           "proc"
1888           "putc"
1889           "puts"
1890           "raise"
1891           "rand"
1892           "readline"
1893           "readlines"
1894           "require"
1895           "require_relative"
1896           "sleep"
1897           "spawn"
1898           "sprintf"
1899           "srand"
1900           "syscall"
1901           "system"
1902           "throw"
1903           "trap"
1904           "warn"
1905           ;; keyword-like private methods on Module
1906           "alias_method"
1907           "attr"
1908           "attr_accessor"
1909           "attr_reader"
1910           "attr_writer"
1911           "define_method"
1912           "extend"
1913           "include"
1914           "module_function"
1915           "prepend"
1916           "private"
1917           "protected"
1918           "public"
1919           "refine"
1920           "using")
1921         'symbols))
1922      (1 font-lock-builtin-face))
1923     ;; Here-doc beginnings.
1924     (,ruby-here-doc-beg-re
1925      (0 (unless (ruby-singleton-class-p (match-beginning 0))
1926           'font-lock-string-face)))
1927     ;; Perl-ish keywords.
1928     "\\_<\\(?:BEGIN\\|END\\)\\_>\\|^__END__$"
1929     ;; Variables.
1930     (,(concat ruby-font-lock-keyword-beg-re
1931               "\\_<\\(nil\\|self\\|true\\|false\\)\\_>")
1932      1 font-lock-variable-name-face)
1933     ;; Keywords that evaluate to certain values.
1934     ("\\_<__\\(?:LINE\\|ENCODING\\|FILE\\)__\\_>"
1935      (0 font-lock-variable-name-face))
1936     ;; Symbols.
1937     ("\\(^\\|[^:]\\)\\(:\\([-+~]@?\\|[/%&|^`]\\|\\*\\*?\\|<\\(<\\|=>?\\)?\\|>[>=]?\\|===?\\|=~\\|![~=]?\\|\\[\\]=?\\|@?\\(\\w\\|_\\)+\\([!?=]\\|\\b_*\\)\\|#{[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\)\\)"
1938      2 font-lock-constant-face)
1939     ;; Variables.
1940     ("\\(\\$\\([^a-zA-Z0-9 \n]\\|[0-9]\\)\\)\\W"
1941      1 font-lock-variable-name-face)
1942     ("\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+"
1943      0 font-lock-variable-name-face)
1944     ;; Constants.
1945     ("\\(?:\\_<\\|::\\)\\([A-Z]+\\(\\w\\|_\\)*\\)"
1946      1 (unless (eq ?\( (char-after)) font-lock-type-face))
1947     ("\\(^\\s *\\|[\[\{\(,]\\s *\\|\\sw\\s +\\)\\(\\(\\sw\\|_\\)+\\):[^:]"
1948      (2 font-lock-constant-face))
1949     ;; Conversion methods on Kernel.
1950     (,(concat ruby-font-lock-keyword-beg-re
1951               (regexp-opt '("Array" "Complex" "Float" "Hash"
1952                             "Integer" "Rational" "String") 'symbols))
1953      (1 font-lock-builtin-face))
1954     ;; Expression expansion.
1955     (ruby-match-expression-expansion
1956      2 font-lock-variable-name-face t)
1957     ;; Negation char.
1958     ("[^[:alnum:]_]\\(!\\)[^=]"
1959      1 font-lock-negation-char-face)
1960     ;; Character literals.
1961     ;; FIXME: Support longer escape sequences.
1962     ("\\_<\\?\\\\?\\S " 0 font-lock-string-face)
1963     )
1964   "Additional expressions to highlight in Ruby mode.")
1965
1966 (defun ruby-match-expression-expansion (limit)
1967   (let* ((prop 'ruby-expansion-match-data)
1968          (pos (next-single-char-property-change (point) prop nil limit))
1969          value)
1970     (when (and pos (> pos (point)))
1971       (goto-char pos)
1972       (or (and (setq value (get-text-property pos prop))
1973                (progn (set-match-data value) t))
1974           (ruby-match-expression-expansion limit)))))
1975
1976 ;;;###autoload
1977 (define-derived-mode ruby-mode prog-mode "Ruby"
1978   "Major mode for editing Ruby code.
1979
1980 \\{ruby-mode-map}"
1981   (ruby-mode-variables)
1982
1983   (setq-local imenu-create-index-function 'ruby-imenu-create-index)
1984   (setq-local add-log-current-defun-function 'ruby-add-log-current-method)
1985   (setq-local beginning-of-defun-function 'ruby-beginning-of-defun)
1986   (setq-local end-of-defun-function 'ruby-end-of-defun)
1987
1988   (add-hook 'after-save-hook 'ruby-mode-set-encoding nil 'local)
1989
1990   (setq-local electric-indent-chars (append '(?\{ ?\}) electric-indent-chars))
1991
1992   (setq-local font-lock-defaults '((ruby-font-lock-keywords) nil nil))
1993   (setq-local font-lock-keywords ruby-font-lock-keywords)
1994   (setq-local font-lock-syntax-table ruby-font-lock-syntax-table)
1995
1996   (setq-local syntax-propertize-function #'ruby-syntax-propertize-function))
1997
1998 ;;; Invoke ruby-mode when appropriate
1999
2000 ;;;###autoload
2001 (add-to-list 'auto-mode-alist
2002              (cons (purecopy (concat "\\(?:\\."
2003                                      "rb\\|ru\\|rake\\|thor"
2004                                      "\\|jbuilder\\|gemspec"
2005                                      "\\|/"
2006                                      "\\(?:Gem\\|Rake\\|Cap\\|Thor"
2007                                      "Vagrant\\|Guard\\)file"
2008                                      "\\)\\'")) 'ruby-mode))
2009
2010 ;;;###autoload
2011 (dolist (name (list "ruby" "rbx" "jruby" "ruby1.9" "ruby1.8"))
2012   (add-to-list 'interpreter-mode-alist (cons (purecopy name) 'ruby-mode)))
2013
2014 (provide 'ruby-mode)
2015
2016 ;;; ruby-mode.el ends here