lisp/eshell/em-alias.el

   1 ;;; em-alias.el --- creation and management of command aliases
   2
   3 ;; Copyright (C) 1999, 2000, 2002, 2003, 2004,
   4 ;;   2005, 2006 Free Software Foundation, Inc.
   5
   6 ;; Author: John Wiegley <johnw@gnu.org>
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23 ;; Boston, MA 02110-1301, USA.
  24
  25 (provide 'em-alias)
  26
  27 (eval-when-compile (require 'esh-maint))
  28 (require 'eshell)
  29
  30 (defgroup eshell-alias nil
  31   "Command aliases allow for easy definition of alternate commands."
  32   :tag "Command aliases"
  33   ;; :link '(info-link "(eshell)Command aliases")
  34   :group 'eshell-module)
  35
  36 ;;; Commentary:
  37
  38 ;; Command aliases greatly simplify the definition of new commands.
  39 ;; They exist as an alternative to alias functions, which are
  40 ;; otherwise quite superior, being more flexible and natural to the
  41 ;; Emacs Lisp environment (if somewhat trickier to define; [Alias
  42 ;; functions]).
  43 ;;
  44 ;;;_* Creating aliases
  45 ;;
  46 ;; The user interface is simple: type 'alias' followed by the command
  47 ;; name followed by the definition.  Argument references are made
  48 ;; using '$1', '$2', etc., or '$*'.  For example:
  49 ;;
  50 ;;   alias ll 'ls -l $*'
  51 ;;
  52 ;; This will cause the command 'll NEWS' to be replaced by 'ls -l
  53 ;; NEWS'.  This is then passed back to the command parser for
  54 ;; reparsing.{Only the command text specified in the alias definition
  55 ;; will be reparsed.  Argument references (such as '$*') are handled
  56 ;; using variable values, which means that the expansion will not be
  57 ;; reparsed, but used directly.}
  58 ;;
  59 ;; To delete an alias, specify its name without a definition:
  60 ;;
  61 ;;   alias ll
  62 ;;
  63 ;; Aliases are written to disk immediately after being defined or
  64 ;; deleted.  The filename in which they are kept is defined by the
  65 ;; following variable:
  66
  67 (defcustom eshell-aliases-file (concat eshell-directory-name "alias")
  68   "*The file in which aliases are kept.
  69 Whenever an alias is defined by the user, using the `alias' command,
  70 it will be written to this file.  Thus, alias definitions (and
  71 deletions) are always permanent.  This approach was chosen for the
  72 sake of simplicity, since that's pretty much the only benefit to be
  73 gained by using this module."
  74   :type 'file
  75   :group 'eshell-alias)
  76
  77 ;;;
  78 ;; The format of this file is quite basic.  It specifies the alias
  79 ;; definitions in almost exactly the same way that the user entered
  80 ;; them, minus any argument quoting (since interpolation is not done
  81 ;; when the file is read).  Hence, it is possible to add new aliases
  82 ;; to the alias file directly, using a text editor rather than the
  83 ;; `alias' command.  Or, this method can be used for editing aliases
  84 ;; that have already defined.
  85 ;;
  86 ;; Here is an example of a few different aliases, and they would
  87 ;; appear in the aliases file:
  88 ;;
  89 ;;   alias clean rm -fr **/.#*~
  90 ;;   alias commit cvs commit -m changes $*
  91 ;;   alias ll ls -l $*
  92 ;;   alias info (info)
  93 ;;   alias reindex glimpseindex -o ~/Mail
  94 ;;   alias compact for i in ~/Mail/**/*~*.bz2(Lk+50) { bzip2 -9v $i }
  95 ;;
  96 ;;;_* Auto-correction of bad commands
  97 ;;
  98 ;; When a user enters the same unknown command many times during a
  99 ;; session, it is likely that they are experiencing a spelling
 100 ;; difficulty associated with a certain command.  To combat this,
 101 ;; Eshell will offer to automatically define an alias for that
 102 ;; mispelled command, once a given tolerance threshold has been
 103 ;; reached.
 104
 105 (defcustom eshell-bad-command-tolerance 3
 106   "*The number of failed commands to ignore before creating an alias."
 107   :type 'integer
 108   ;; :link '(custom-manual "(eshell)Auto-correction of bad commands")
 109   :group 'eshell-alias)
 110
 111 ;;;
 112 ;; Whenever the same bad command name is encountered this many times,
 113 ;; the user will be prompted in the minibuffer to provide an alias
 114 ;; name.  An alias definition will then be created which will result
 115 ;; in an equal call to the correct name.  In this way, Eshell
 116 ;; gradually learns about the commands that the user mistypes
 117 ;; frequently, and will automatically correct them!
 118 ;;
 119 ;; Note that a '$*' is automatically appended at the end of the alias
 120 ;; definition, so that entering it is unnecessary when specifying the
 121 ;; corrected command name.
 122
 123 ;;; Code:
 124
 125 (defcustom eshell-alias-load-hook '(eshell-alias-initialize)
 126   "*A hook that gets run when `eshell-alias' is loaded."
 127   :type 'hook
 128   :group 'eshell-alias)
 129
 130 (defvar eshell-command-aliases-list nil
 131   "A list of command aliases currently defined by the user.
 132 Each element of this alias is a list of the form:
 133
 134   (NAME DEFINITION)
 135
 136 Where NAME is the textual name of the alias, and DEFINITION is the
 137 command string to replace that command with.
 138
 139 Note: this list should not be modified in your '.emacs' file.  Rather,
 140 any desired alias definitions should be declared using the `alias'
 141 command, which will automatically write them to the file named by
 142 `eshell-aliases-file'.")
 143
 144 (put 'eshell-command-aliases-list 'risky-local-variable t)
 145
 146 (defvar eshell-failed-commands-alist nil
 147   "An alist of command name failures.")
 148
 149 (defun eshell-alias-initialize ()
 150   "Initialize the alias handling code."
 151   (make-local-variable 'eshell-failed-commands-alist)
 152   (add-hook 'eshell-alternate-command-hook 'eshell-fix-bad-commands t t)
 153   (eshell-read-aliases-list)
 154   (add-hook 'eshell-named-command-hook 'eshell-maybe-replace-by-alias t t)
 155   (make-local-variable 'eshell-complex-commands)
 156   (add-to-list 'eshell-complex-commands 'eshell-command-aliased-p))
 157
 158 (defun eshell-command-aliased-p (name)
 159   (assoc name eshell-command-aliases-list))
 160
 161 (defun eshell/alias (&optional alias &rest definition)
 162   "Define an ALIAS in the user's alias list using DEFINITION."
 163   (if (not alias)
 164       (eshell-for alias eshell-command-aliases-list
 165         (eshell-print (apply 'format "alias %s %s\n" alias)))
 166     (if (not definition)
 167         (setq eshell-command-aliases-list
 168               (delq (assoc alias eshell-command-aliases-list)
 169                     eshell-command-aliases-list))
 170       (and (stringp definition)
 171            (set-text-properties 0 (length definition) nil definition))
 172       (let ((def (assoc alias eshell-command-aliases-list))
 173             (alias-def (list alias
 174                              (eshell-flatten-and-stringify definition))))
 175         (if def
 176             (setq eshell-command-aliases-list
 177                   (delq def eshell-command-aliases-list)))
 178         (setq eshell-command-aliases-list
 179               (cons alias-def eshell-command-aliases-list))))
 180     (eshell-write-aliases-list))
 181   nil)
 182
 183 (defun pcomplete/eshell-mode/alias ()
 184   "Completion function for Eshell's `alias' command."
 185   (pcomplete-here (eshell-alias-completions pcomplete-stub)))
 186
 187 (defun eshell-read-aliases-list ()
 188   "Read in an aliases list from `eshell-aliases-file'."
 189   (let ((file eshell-aliases-file))
 190     (when (file-readable-p file)
 191       (setq eshell-command-aliases-list
 192             (with-temp-buffer
 193               (let (eshell-command-aliases-list)
 194                 (insert-file-contents file)
 195                 (while (not (eobp))
 196                   (if (re-search-forward
 197                        "^alias\\s-+\\(\\S-+\\)\\s-+\\(.+\\)")
 198                       (setq eshell-command-aliases-list
 199                             (cons (list (match-string 1)
 200                                         (match-string 2))
 201                                   eshell-command-aliases-list)))
 202                   (forward-line 1))
 203                 eshell-command-aliases-list))))))
 204
 205 (defun eshell-write-aliases-list ()
 206   "Write out the current aliases into `eshell-aliases-file'."
 207   (if (file-writable-p (file-name-directory eshell-aliases-file))
 208       (let ((eshell-current-handles
 209              (eshell-create-handles eshell-aliases-file 'overwrite)))
 210         (eshell/alias)
 211         (eshell-close-handles 0))))
 212
 213 (defsubst eshell-lookup-alias (name)
 214   "Check whether NAME is aliased.  Return the alias if there is one."
 215   (assoc name eshell-command-aliases-list))
 216
 217 (defvar eshell-prevent-alias-expansion nil)
 218
 219 (defun eshell-maybe-replace-by-alias (command args)
 220   "If COMMAND has an alias definition, call that instead using ARGS."
 221   (unless (and eshell-prevent-alias-expansion
 222                (member command eshell-prevent-alias-expansion))
 223     (let ((alias (eshell-lookup-alias command)))
 224       (if alias
 225           (throw 'eshell-replace-command
 226                  (list
 227                   'let
 228                   (list
 229                    (list 'eshell-command-name
 230                          (list 'quote eshell-last-command-name))
 231                    (list 'eshell-command-arguments
 232                          (list 'quote eshell-last-arguments))
 233                    (list 'eshell-prevent-alias-expansion
 234                          (list 'quote
 235                                (cons command
 236                                      eshell-prevent-alias-expansion))))
 237                   (eshell-parse-command (nth 1 alias))))))))
 238
 239 (defun eshell-alias-completions (name)
 240   "Find all possible completions for NAME.
 241 These are all the command aliases which begin with NAME."
 242   (let (completions)
 243     (eshell-for alias eshell-command-aliases-list
 244       (if (string-match (concat "^" name) (car alias))
 245           (setq completions (cons (car alias) completions))))
 246     completions))
 247
 248 (defun eshell-fix-bad-commands (name)
 249   "If the user repeatedly a bad command NAME, make an alias for them."
 250   (ignore
 251    (unless (file-name-directory name)
 252      (let ((entry (assoc name eshell-failed-commands-alist)))
 253        (if (not entry)
 254            (setq eshell-failed-commands-alist
 255                  (cons (cons name 1) eshell-failed-commands-alist))
 256          (if (< (cdr entry) eshell-bad-command-tolerance)
 257              (setcdr entry (1+ (cdr entry)))
 258            (let ((alias (concat
 259                          (read-string
 260                           (format "Define alias for \"%s\": " name))
 261                          " $*")))
 262              (eshell/alias name alias)
 263              (throw 'eshell-replace-command
 264                     (list
 265                      'let
 266                      (list
 267                       (list 'eshell-command-name
 268                             (list 'quote name))
 269                       (list 'eshell-command-arguments
 270                             (list 'quote eshell-last-arguments))
 271                       (list 'eshell-prevent-alias-expansion
 272                             (list 'quote
 273                                   (cons name
 274                                         eshell-prevent-alias-expansion))))
 275                      (eshell-parse-command alias))))))))))
 276
 277 ;;; arch-tag: 8b018fc1-4e07-4ccc-aa73-c0a1ba361f82
 278 ;;; em-alias.el ends here