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1 ;;; em-alias.el --- creation and management of command aliases -*- lexical-binding:t -*-
3 ;; Copyright (C) 1999-2016 Free Software Foundation, Inc.
5 ;; Author: John Wiegley <johnw@gnu.org>
7 ;; This file is part of GNU Emacs.
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.
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.
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/>.
22 ;;; Commentary:
24 ;; Command aliases greatly simplify the definition of new commands.
25 ;; They exist as an alternative to alias functions, which are
26 ;; otherwise quite superior, being more flexible and natural to the
27 ;; Emacs Lisp environment (if somewhat trickier to define; [Alias
28 ;; functions]).
29 ;;
30 ;;;_* Creating aliases
31 ;;
32 ;; The user interface is simple: type 'alias' followed by the command
33 ;; name followed by the definition. Argument references are made
34 ;; using '$1', '$2', etc., or '$*'. For example:
35 ;;
36 ;; alias ll 'ls -l $*'
37 ;;
38 ;; This will cause the command 'll NEWS' to be replaced by 'ls -l
39 ;; NEWS'. This is then passed back to the command parser for
40 ;; reparsing.{Only the command text specified in the alias definition
41 ;; will be reparsed. Argument references (such as '$*') are handled
42 ;; using variable values, which means that the expansion will not be
43 ;; reparsed, but used directly.}
44 ;;
45 ;; To delete an alias, specify its name without a definition:
46 ;;
47 ;; alias ll
48 ;;
49 ;; Aliases are written to disk immediately after being defined or
50 ;; deleted. The filename in which they are kept is defined by the
51 ;; variable eshell-aliases-file.
53 ;; The format of this file is quite basic. It specifies the alias
54 ;; definitions in almost exactly the same way that the user entered
55 ;; them, minus any argument quoting (since interpolation is not done
56 ;; when the file is read). Hence, it is possible to add new aliases
57 ;; to the alias file directly, using a text editor rather than the
58 ;; `alias' command. Or, this method can be used for editing aliases
59 ;; that have already defined.
60 ;;
61 ;; Here is an example of a few different aliases, and they would
62 ;; appear in the aliases file:
63 ;;
64 ;; alias clean rm -fr **/.#*~
65 ;; alias commit cvs commit -m changes $*
66 ;; alias ll ls -l $*
67 ;; alias info (info)
68 ;; alias reindex glimpseindex -o ~/Mail
69 ;; alias compact for i in ~/Mail/**/*~*.bz2(Lk+50) { bzip2 -9v $i }
70 ;;
71 ;;;_* Auto-correction of bad commands
72 ;;
73 ;; When a user enters the same unknown command many times during a
74 ;; session, it is likely that they are experiencing a spelling
75 ;; difficulty associated with a certain command. To combat this,
76 ;; Eshell will offer to automatically define an alias for that
77 ;; misspelled command, once a given tolerance threshold has been
78 ;; reached.
80 ;; Whenever the same bad command name is encountered
81 ;; `eshell-bad-command-tolerance' times, the user will be prompted in
82 ;; the minibuffer to provide an alias name. An alias definition will
83 ;; then be created which will result in an equal call to the correct
84 ;; name. In this way, Eshell gradually learns about the commands that
85 ;; the user mistypes frequently, and will automatically correct them!
86 ;;
87 ;; Note that a '$*' is automatically appended at the end of the alias
88 ;; definition, so that entering it is unnecessary when specifying the
89 ;; corrected command name.
91 ;;; Code:
95 ;;;###autoload
98 "Command aliases allow for easy definition of alternate commands."
100 ;; :link '(info-link "(eshell)Command aliases")
104 "The file in which aliases are kept.
105 Whenever an alias is defined by the user, using the `alias' command,
106 it will be written to this file. Thus, alias definitions (and
107 deletions) are always permanent. This approach was chosen for the
108 sake of simplicity, since that's pretty much the only benefit to be
109 gained by using this module."
114 "The number of failed commands to ignore before creating an alias."
116 ;; :link '(custom-manual "(eshell)Auto-correction of bad commands")
120 "A hook that gets run when `eshell-alias' is loaded."
126 "A list of command aliases currently defined by the user.
127 Each element of this alias is a list of the form:
129 (NAME DEFINITION)
131 Where NAME is the textual name of the alias, and DEFINITION is the
132 command string to replace that command with.
134 Note: this list should not be modified in your init file.
135 Rather, any desired alias definitions should be declared using
136 the `alias' command, which will automatically write them to the
145 "Initialize the alias handling code."
157 "Define an ALIAS in the user's alias list using DEFINITION."
164 eshell-command-aliases-list))
176 nil)
182 "Completion function for Eshell's `alias' command."
186 "Read in an aliases list from `eshell-aliases-file'."
199 eshell-command-aliases-list)))
201 eshell-command-aliases-list))))))
204 "Write out the current aliases into `eshell-aliases-file'."
212 "Check whether NAME is aliased. Return the alias if there is one."
218 "If COMMAND has an alias definition, call that instead using ARGS."
231 "Find all possible completions for NAME.
232 These are all the command aliases which begin with NAME."
237 completions))
240 "If the user repeatedly a bad command NAME, make an alias for them."
256 'let
265 eshell-prevent-alias-expansion))))
270 ;; Local Variables:
271 ;; generated-autoload-file: "esh-groups.el"
272 ;; End:
274 ;;; em-alias.el ends here