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   1 ;;; esh-opt.el --- command options processing
   2
   3 ;; Copyright (C) 1999-2013 Free Software Foundation, Inc.
   4
   5 ;; Author: John Wiegley <johnw@gnu.org>
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software: you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;;; Code:
  25
  26 (provide 'esh-opt)
  27
  28 (require 'esh-ext)
  29
  30 ;; Unused.
  31 ;;; (defgroup eshell-opt nil
  32 ;;;   "The options processing code handles command argument parsing for
  33 ;;; Eshell commands implemented in Lisp."
  34 ;;;   :tag "Command options processing"
  35 ;;;   :group 'eshell)
  36
  37 ;;; User Functions:
  38
  39 (defmacro eshell-eval-using-options (name macro-args options &rest body-forms)
  40   "Process NAME's MACRO-ARGS using a set of command line OPTIONS.
  41 After doing so, stores settings in local symbols as declared by OPTIONS;
  42 then evaluates BODY-FORMS -- assuming all was OK.
  43
  44 OPTIONS is a list, beginning with one or more elements of the form:
  45 \(SHORT LONG VALUE SYMBOL HELP-STRING)
  46 Each of these elements represents a particular command-line switch.
  47
  48 SHORT is either nil, or a character that can be used as a switch -SHORT.
  49 LONG is either nil, or a string that can be used as a switch --LONG.
  50 At least one of SHORT and LONG must be non-nil.
  51 VALUE is the value associated with the option.  It can be either:
  52   t   - the option needs a value to be specified after the switch;
  53   nil - the option is given the value t;
  54   anything else - specifies the actual value for the option.
  55 SYMBOL is either nil, or the name of the Lisp symbol that will be bound
  56 to VALUE.  A nil SYMBOL calls `eshell-show-usage', and so is appropriate
  57 for a \"--help\" type option.
  58 HELP-STRING is a documentation string for the option.
  59
  60 Any remaining elements of OPTIONS are :KEYWORD arguments.  Some take
  61 arguments, some do not.  The recognized :KEYWORDS are:
  62
  63 :external STRING
  64   STRING is an external command to run if there are unknown switches.
  65
  66 :usage STRING
  67   STRING is the initial part of the command's documentation string.
  68   It appears before the options are listed.
  69
  70 :post-usage STRING
  71   STRING is an optional trailing part of the command's documentation string.
  72   It appears after the options, but before the final part of the
  73   documentation about the associated external command (if there is one).
  74
  75 :show-usage
  76   If present, then show the usage message if the command is called with no
  77   arguments.
  78
  79 :preserve-args
  80   If present, do not pass MACRO-ARGS through `eshell-flatten-list'
  81 and `eshell-stringify-list'.
  82
  83 For example, OPTIONS might look like:
  84
  85   '((?C  nil         nil multi-column    \"multi-column display\")
  86     (nil \"help\"      nil nil             \"show this usage display\")
  87     (?r  \"reverse\"   nil reverse-list    \"reverse order while sorting\")
  88     :external \"ls\"
  89     :usage \"[OPTION]... [FILE]...
  90   List information about the FILEs (the current directory by default).
  91   Sort entries alphabetically across.\")
  92
  93 `eshell-eval-using-options' returns the value of the last form in
  94 BODY-FORMS.  If instead an external command is run (because of
  95 an unknown option), the tag `eshell-external' will be thrown with
  96 the new process for its value.
  97
  98 Lastly, any remaining arguments will be available in a locally
  99 interned variable `args' (created using a `let' form)."
 100   (declare (debug (form form sexp body)))
 101   `(let ((temp-args
 102           ,(if (memq ':preserve-args (cadr options))
 103                macro-args
 104              (list 'eshell-stringify-list
 105                    (list 'eshell-flatten-list macro-args)))))
 106      (let ,(append (delq nil (mapcar (lambda (opt)
 107                                        (and (listp opt) (nth 3 opt)))
 108                                      (cadr options)))
 109                    '(usage-msg last-value ext-command args))
 110        ;; FIXME: `options' ends up hiding some variable names under `quote',
 111        ;; which is incompatible with lexical scoping!!
 112        (eshell-do-opt ,name ,options (lambda () ,@body-forms)))))
 113
 114 ;;; Internal Functions:
 115
 116 (defvar temp-args)
 117 (defvar last-value)
 118 (defvar usage-msg)
 119 (defvar ext-command)
 120 ;; Documented part of the interface; see eshell-eval-using-options.
 121 (defvar args)
 122
 123 (defun eshell-do-opt (name options body-fun)
 124   "Helper function for `eshell-eval-using-options'.
 125 This code doesn't really need to be macro expanded everywhere."
 126   (setq args temp-args)
 127   (if (setq
 128        ext-command
 129        (catch 'eshell-ext-command
 130          (when (setq
 131                 usage-msg
 132                 (catch 'eshell-usage
 133                   (setq last-value nil)
 134                   (if (and (= (length args) 0)
 135                            (memq ':show-usage options))
 136                       (throw 'eshell-usage
 137                              (eshell-show-usage name options)))
 138                   (setq args (eshell-process-args name args options)
 139                         last-value (funcall body-fun))
 140                   nil))
 141            (error "%s" usage-msg))))
 142       (throw 'eshell-external
 143              (eshell-external-command ext-command args))
 144     last-value))
 145
 146 (defun eshell-show-usage (name options)
 147   "Display the usage message for NAME, using OPTIONS."
 148   (let ((usage (format "usage: %s %s\n\n" name
 149                        (cadr (memq ':usage options))))
 150         (extcmd (memq ':external options))
 151         (post-usage (memq ':post-usage options))
 152         had-option)
 153     (while options
 154       (when (listp (car options))
 155         (let ((opt (car options)))
 156           (setq had-option t)
 157           (cond ((and (nth 0 opt)
 158                       (nth 1 opt))
 159                  (setq usage
 160                        (concat usage
 161                                (format "    %-20s %s\n"
 162                                        (format "-%c, --%s" (nth 0 opt)
 163                                                (nth 1 opt))
 164                                        (nth 4 opt)))))
 165                 ((nth 0 opt)
 166                  (setq usage
 167                        (concat usage
 168                                (format "    %-20s %s\n"
 169                                        (format "-%c" (nth 0 opt))
 170                                        (nth 4 opt)))))
 171                 ((nth 1 opt)
 172                  (setq usage
 173                        (concat usage
 174                                (format "    %-20s %s\n"
 175                                        (format "    --%s" (nth 1 opt))
 176                                        (nth 4 opt)))))
 177                 (t (setq had-option nil)))))
 178       (setq options (cdr options)))
 179     (if post-usage
 180         (setq usage (concat usage (and had-option "\n")
 181                             (cadr post-usage))))
 182     (when extcmd
 183       (setq extcmd (eshell-search-path (cadr extcmd)))
 184       (if extcmd
 185           (setq usage
 186                 (concat usage
 187                         (format "
 188 This command is implemented in Lisp.  If an unrecognized option is
 189 passed to this command, the external version '%s'
 190 will be called instead." extcmd)))))
 191     (throw 'eshell-usage usage)))
 192
 193 (defun eshell-set-option (name ai opt options)
 194   "Using NAME's remaining args (index AI), set the OPT within OPTIONS.
 195 If the option consumes an argument for its value, the argument list
 196 will be modified."
 197   (if (not (nth 3 opt))
 198       (eshell-show-usage name options)
 199     (if (eq (nth 2 opt) t)
 200         (if (> ai (length args))
 201             (error "%s: missing option argument" name)
 202           (set (nth 3 opt) (nth ai args))
 203           (if (> ai 0)
 204               (setcdr (nthcdr (1- ai) args) (nthcdr (1+ ai) args))
 205             (setq args (cdr args))))
 206       (set (nth 3 opt) (or (nth 2 opt) t)))))
 207
 208 (defun eshell-process-option (name switch kind ai options)
 209   "For NAME, process SWITCH (of type KIND), from args at index AI.
 210 The SWITCH will be looked up in the set of OPTIONS.
 211
 212 SWITCH should be either a string or character.  KIND should be the
 213 integer 0 if it's a character, or 1 if it's a string.
 214
 215 The SWITCH is then be matched against OPTIONS.  If no matching handler
 216 is found, and an :external command is defined (and available), it will
 217 be called; otherwise, an error will be triggered to say that the
 218 switch is unrecognized."
 219   (let* ((opts options)
 220          found)
 221     (while opts
 222       (if (and (listp (car opts))
 223                (nth kind (car opts))
 224                (equal switch (nth kind (car opts))))
 225           (progn
 226             (eshell-set-option name ai (car opts) options)
 227             (setq found t opts nil))
 228         (setq opts (cdr opts))))
 229     (unless found
 230       (let ((extcmd (memq ':external options)))
 231         (when extcmd
 232           (setq extcmd (eshell-search-path (cadr extcmd)))
 233           (if extcmd
 234               (throw 'eshell-ext-command extcmd)
 235             (if (characterp switch)
 236                 (error "%s: unrecognized option -%c" name switch)
 237               (error "%s: unrecognized option --%s" name switch))))))))
 238
 239 (defun eshell-process-args (name args options)
 240   "Process the given ARGS using OPTIONS.
 241 This assumes that symbols have been intern'd by `eshell-eval-using-options'."
 242   (let ((ai 0) arg)
 243     (while (< ai (length args))
 244       (setq arg (nth ai args))
 245       (if (not (and (stringp arg)
 246                     (string-match "^-\\(-\\)?\\(.*\\)" arg)))
 247           (setq ai (1+ ai))
 248         (let* ((dash (match-string 1 arg))
 249                (switch (match-string 2 arg)))
 250           (if (= ai 0)
 251               (setq args (cdr args))
 252             (setcdr (nthcdr (1- ai) args) (nthcdr (1+ ai) args)))
 253           (if dash
 254               (if (> (length switch) 0)
 255                   (eshell-process-option name switch 1 ai options)
 256                 (setq ai (length args)))
 257             (let ((len (length switch))
 258                   (index 0))
 259               (while (< index len)
 260                 (eshell-process-option name (aref switch index) 0 ai options)
 261                 (setq index (1+ index)))))))))
 262   args)
 263
 264 ;;; esh-opt.el ends here