path: root/Doc/Zsh/contrib.yo

texinode(User Contributions)()(Zftp Function System)(Top)
chapter(User Contributions)
cindex(user contributions)
sect(Description)

The Zsh source distribution includes a number of items contributed by the
user community.  These are not inherently a part of the shell, and some
may not be available in every zsh installation.  The most significant of
these are documented here.  For documentation on other contributed items
such as shell functions, look for comments in the function source files.

startmenu()
menu(Utilities)
menu(Prompt Themes)
menu(ZLE Functions)
menu(Exception Handling)
menu(MIME Functions)
menu(Other Functions)
endmenu()

texinode(Utilities)(Prompt Themes)()(User Contributions)
sect(Utilities)

subsect(Accessing On-Line Help)
cindex(helpfiles utility)

The key sequence tt(ESC h) is normally bound by ZLE to execute the
tt(run-help) widget (see
ifzman(zmanref(zshzle))\
ifnzman(noderef(Zsh Line Editor))\
).  This invokes the tt(run-help) command with the command word from the
current input line as its argument.  By default, tt(run-help) is an alias
for the tt(man) command, so this often fails when the command word is a
shell builtin or a user-defined function.  By redefining the tt(run-help)
alias, one can improve the on-line help provided by the shell.

The tt(helpfiles) utility, found in the tt(Util) directory of the
distribution, is a Perl program that can be used to process the zsh manual
to produce a separate help file for each shell builtin and for many other
shell features as well.  The autoloadable tt(run-help) function, found in
tt(Functions/Misc), searches for these helpfiles and performs several
other tests to produce the most complete help possible for the command.

There may already be a directory of help files on your system; look in
tt(/usr/share/zsh) or tt(/usr/local/share/zsh) and subdirectories below
those, or ask your system administrator.

To create your own help files with tt(helpfiles), choose or create a
directory where the individual command help files will reside.  For
example, you might choose tt(~/zsh_help).  If you unpacked the zsh
distribution in your home directory, you would use the commands:

example(mkdir ~/zsh_help
cd ~/zsh_help
man zshall | colcrt - | \ 
perl ~/zsh-version()/Util/helpfiles)

findex(run-help, use of)
Next, to use the tt(run-help) function, you need to add lines something
like the following to your tt(.zshrc) or equivalent startup file:

example(unalias run-help
autoload run-help
HELPDIR=~/zsh_help)

vindex(HELPDIR)
The tt(HELPDIR) parameter tells tt(run-help) where to look for the help
files.  If your system already has a help file directory installed, set
tt(HELPDIR) to the path of that directory instead.

Note that in order for `tt(autoload run-help)' to work, the tt(run-help)
file must be in one of the directories named in your tt(fpath) array (see
ifzman(zmanref(zshparam))\
ifnzman(noderef(Parameters Used By The Shell))\
).  This should already be the case if you have a standard zsh
installation; if it is not, copy tt(Functions/Misc/run-help) to an
appropriate directory.

subsect(Recompiling Functions)
cindex(functions, recompiling)
cindex(zrecompile utility)

If you frequently edit your zsh functions, or periodically update your zsh
installation to track the latest developments, you may find that function
digests compiled with the tt(zcompile) builtin are frequently out of date
with respect to the function source files.  This is not usually a problem,
because zsh always looks for the newest file when loading a function, but
it may cause slower shell startup and function loading.  Also, if a digest
file is explicitly used as an element of tt(fpath), zsh won't check whether
any of its source files has changed.

The tt(zrecompile) autoloadable function, found in tt(Functions/Misc), can
be used to keep function digests up to date.

startitem()
findex(zrecompile)
xitem(tt(zrecompile) [ tt(-qt) ] [ var(name) ... ])
item(tt(zrecompile) [ tt(-qt) ] tt(-p) var(args) [ tt(-)tt(-) var(args) ... ])(
This tries to find tt(*.zwc) files and automatically re-compile them if at
least one of the original files is newer than the compiled file.  This
works only if the names stored in the compiled files are full paths or are
relative to the directory that contains the tt(.zwc) file.

In the first form, each var(name) is the name of a compiled file or a
directory containing tt(*.zwc) files that should be checked.  If no
arguments are given, the directories and tt(*.zwc) files in tt(fpath) are
used.

When tt(-t) is given, no compilation is performed, but a return status of
zero (true) is set if there are files that need to be re-compiled and
non-zero (false) otherwise.  The tt(-q) option quiets the chatty output
that describes what tt(zrecompile) is doing.

Without the tt(-t) option, the return status is zero if all files that
needed re-compilation could be compiled and non-zero if compilation for at
least one of the files failed.

If the tt(-p) option is given, the var(args) are interpreted as one
or more sets of arguments for tt(zcompile), separated by `tt(-)tt(-)'.
For example:

example(zrecompile -p \ 
           -R ~/.zshrc -- \ 
           -M ~/.zcompdump -- \ 
           ~/zsh/comp.zwc ~/zsh/Completion/*/_*)

This compiles tt(~/.zshrc) into tt(~/.zshrc.zwc) if that doesn't exist or
if it is older than tt(~/.zshrc). The compiled file will be marked for
reading instead of mapping. The same is done for tt(~/.zcompdump) and
tt(~/.zcompdump.zwc), but this compiled file is marked for mapping. The
last line re-creates the file tt(~/zsh/comp.zwc) if any of the files
matching the given pattern is newer than it.

Without the tt(-p) option, tt(zrecompile) does not create function digests
that do not already exist, nor does it add new functions to the digest.
)
enditem()

The following shell loop is an example of a method for creating function
digests for all functions in your tt(fpath), assuming that you have write
permission to the directories:

example(for ((i=1; i <= $#fpath; ++i)); do
  dir=$fpath[i]
  zwc=${dir:t}.zwc
  if [[ $dir == (.|..) || $dir == (.|..)/* ]]; then
    continue
  fi
  files=($dir/*(N-.))
  if [[ -w $dir:h && -n $files ]]; then
    files=(${${(M)files%/*/*}#/})
    if ( cd $dir:h &&
         zrecompile -p -U -z $zwc $files ); then
      fpath[i]=$fpath[i].zwc
    fi
  fi
done)

The tt(-U) and tt(-z) options are appropriate for functions in the default
zsh installation tt(fpath); you may need to use different options for your
personal function directories.

Once the digests have been created and your tt(fpath) modified to refer to
them, you can keep them up to date by running tt(zrecompile) with no
arguments.

subsect(Keyboard Definition)
cindex(keyboard definition)

findex(zkbd)
The large number of possible combinations of keyboards, workstations,
terminals, emulators, and window systems makes it impossible for zsh to
have built-in key bindings for every situation.  The tt(zkbd) utility,
found in Functions/Misc, can help you quickly create key bindings for your
configuration.

Run tt(zkbd) either as an autoloaded function, or as a shell script:

example(zsh -f ~/zsh-version()/Functions/Misc/zkbd)

When you run tt(zkbd), it first asks you to enter your terminal type; if
the default it offers is correct, just press return.  It then asks you to
press a number of different keys to determine characteristics of your
keyboard and terminal; tt(zkbd) warns you if it finds anything out of the
ordinary, such as a Delete key that sends neither tt(^H) nor tt(^?).

The keystrokes read by tt(zkbd) are recorded as a definition for an
associative array named tt(key), written to a file in the subdirectory
tt(.zkbd) within either your tt(HOME) or tt(ZDOTDIR) directory.  The name
of the file is composed from the tt(TERM), tt(VENDOR) and tt(OSTYPE)
parameters, joined by hyphens.

You may read this file into your tt(.zshrc) or another startup file with
the "source" or "." commands, then reference the tt(key) parameter in
bindkey commands, like this:

example(source ${ZDOTDIR:-$HOME}/.zkbd/$TERM-$VENDOR-$OSTYPE
[[ -n ${key[Left]} ]] && bindkey "${key[Left]}" backward-char
[[ -n ${key[Right]} ]] && bindkey "${key[Right]}" forward-char
# etc.)

Note that in order for `tt(autoload zkbd)' to work, the tt(zkdb) file must
be in one of the directories named in your tt(fpath) array (see
ifzman(zmanref(zshparam))\
ifnzman(noderef(Parameters Used By The Shell))\
).  This should already be the case if you have a standard zsh
installation; if it is not, copy tt(Functions/Misc/zkbd) to an
appropriate directory.

subsect(Dumping Shell State)
cindex(reporter utility)

Occasionally you may encounter what appears to be a bug in the shell,
particularly if you are using a beta version of zsh or a development
release.  Usually it is sufficient to send a description of the
problem to one of the zsh mailing lists (see
ifzman(zmanref(zsh))\
ifnzman(noderef(Mailing Lists))\
), but sometimes one of the zsh developers will need to recreate your
environment in order to track the problem down.

The script named tt(reporter), found in the tt(Util) directory of the
distribution, is provided for this purpose.  (It is also possible to
tt(autoload reporter), but tt(reporter) is not installed in tt(fpath)
by default.)  This script outputs a detailed dump of the shell state,
in the form of another script that can be read with `tt(zsh -f)' to
recreate that state.

To use tt(reporter), read the script into your shell with the `tt(.)'
command and redirect the output into a file:

example(. ~/zsh-version()/Util/reporter > zsh.report)

You should check the tt(zsh.report) file for any sensitive information
such as passwords and delete them by hand before sending the script to the
developers.  Also, as the output can be voluminous, it's best to wait for
the developers to ask for this information before sending it.

You can also use tt(reporter) to dump only a subset of the shell state.
This is sometimes useful for creating startup files for the first time.
Most of the output from reporter is far more detailed than usually is
necessary for a startup file, but the tt(aliases), tt(options), and
tt(zstyles) states may be useful because they include only changes from
the defaults.  The tt(bindings) state may be useful if you have created
any of your own keymaps, because tt(reporter) arranges to dump the keymap
creation commands as well as the bindings for every keymap.

As is usual with automated tools, if you create a startup file with
tt(reporter), you should edit the results to remove unnecessary commands.
Note that if you're using the new completion system, you should em(not)
dump the tt(functions) state to your startup files with tt(reporter); use
the tt(compdump) function instead (see
ifzman(zmanref(zshcompsys))\
ifnzman(noderef(Completion System))\
).

startitem()
item(tt(reporter) [ var(state) ... ])(
findex(reporter)
Print to standard output the indicated subset of the current shell state.
The var(state) arguments may be one or more of:

startsitem()
sitem(tt(all))(Output everything listed below.)
sitem(tt(aliases))(Output alias definitions.)
sitem(tt(bindings))(Output ZLE key maps and bindings.)
sitem(tt(completion))(Output old-style tt(compctl) commands.
New completion is covered by tt(functions) and tt(zstyles).)
sitem(tt(functions))(Output autoloads and function definitions.)
sitem(tt(limits))(Output tt(limit) commands.)
sitem(tt(options))(Output tt(setopt) commands.)
sitem(tt(styles))(Same as tt(zstyles).)
sitem(tt(variables))(Output shell parameter assignments, plus tt(export)
commands for any environment variables.)
sitem(tt(zstyles))(Output tt(zstyle) commands.)
endsitem()

If the var(state) is omitted, tt(all) is assumed.
)

With the exception of `tt(all)', every var(state) can be abbreviated by
any prefix, even a single letter; thus tt(a) is the same as tt(aliases),
tt(z) is the same as tt(zstyles), etc.
enditem()

texinode(Prompt Themes)(ZLE Functions)(Utilities)(User Contributions)
sect(Prompt Themes)

subsect(Installation)

You should make sure all the functions from the tt(Functions/Prompts)
directory of the source distribution are available; they all begin with
the string `tt(prompt_)' except for the special function`tt(promptinit)'.
You also need the `tt(colors)' function from tt(Functions/Misc).  All of
these functions may already have been installed on your system; if not,
you will need to find them and copy them.  The directory should appear as
one of the elements of the tt(fpath) array (this should already be the
case if they were installed), and at least the function tt(promptinit)
should be autoloaded; it will autoload the rest.  Finally, to initialize
the use of the system you need to call the tt(promptinit) function.  The
following code in your tt(.zshrc) will arrange for this; assume the
functions are stored in the directory tt(~/myfns):

example(fpath=(~/myfns $fpath)
autoload -U promptinit
promptinit)

subsect(Theme Selection)

Use the tt(prompt) command to select your preferred theme.  This command
may be added to your tt(.zshrc) following the call to tt(promptinit) in
order to start zsh with a theme already selected.

startitem()
xitem(tt(prompt) [ tt(-c) | tt(-l) ])
xitem(tt(prompt) [ tt(-p) | tt(-h) ] [ var(theme) ... ])
item(tt(prompt) [ tt(-s) ] var(theme) [ var(arg) ... ])(
Set or examine the prompt theme.  With no options and a var(theme)
argument, the theme with that name is set as the current theme.  The
available themes are determined at run time; use the tt(-l) option to see
a list.  The special var(theme) `tt(random)' selects at random one of the
available themes and sets your prompt to that.

In some cases the var(theme) may be modified by one or more arguments,
which should be given after the theme name.  See the help for each theme
for descriptions of these arguments.

Options are:

startsitem()
sitem(tt(-c))(Show the currently selected theme and its parameters, if any.)
sitem(tt(-l))(List all available prompt themes.)
sitem(tt(-p))(Preview the theme named by var(theme), or all themes if no
var(theme) is given.)
sitem(tt(-h))(Show help for the theme named by var(theme), or for the
tt(prompt) function if no var(theme) is given.)
sitem(tt(-s))(Set var(theme) as the current theme and save state.)
endsitem()
)
item(tt(prompt_)var(theme)tt(_setup))(
Each available var(theme) has a setup function which is called by the
tt(prompt) function to install that theme.  This function may define
other functions as necessary to maintain the prompt, including functions
used to preview the prompt or provide help for its use.  You should not
normally call a theme's setup function directly.
)
enditem()

texinode(ZLE Functions)(Exception Handling)(Prompt Themes)(User Contributions)
sect(ZLE Functions)

subsect(Widgets)

These functions all implement user-defined ZLE widgets (see
ifzman(zmanref(zshzle))\
ifnzman(noderef(Zsh Line Editor))\
) which can be bound to keystrokes in interactive shells.  To use them,
your tt(.zshrc) should contain lines of the form

example(autoload var(function)
zle -N var(function))

followed by an appropriate tt(bindkey) command to associate the function
with a key sequence.  Suggested bindings are described below.

startitem()
item(bash-style word functions)(
If you are looking for functions to implement moving over and editing
words in the manner of bash, where only alphanumeric characters are
considered word characters, you can use the functions described in
the next section.  The following is sufficient:

example(autoload -U select-word-style
select-word-style bash)

)
tindex(forward-word-match)
tindex(backward-word-match)
tindex(kill-word-match)
tindex(backward-kill-word-match)
tindex(transpose-words-match)
tindex(capitalize-word-match)
tindex(up-case-word-match)
tindex(down-case-word-match)
tindex(select-word-style)
tindex(match-words-by-style)
xitem(tt(forward-word-match), tt(backward-word-match))
xitem(tt(kill-word-match), tt(backward-kill-word-match))
xitem(tt(transpose-words-match), tt(capitalize-word-match))
xitem(tt(up-case-word-match), tt(down-case-word-match))
item(tt(select-word-style), tt(match-words-by-style))(
The eight `tt(-match)' functions are drop-in replacements for the
builtin widgets without the suffix.  By default they behave in a similar
way.  However, by the use of styles and the function tt(select-word-style),
the way words are matched can be altered.

The simplest way of configuring the functions is to use
tt(select-word-style), which can either be called as a normal function with
the appropriate argument, or invoked as a user-defined widget that will
prompt for the first character of the word style to be used.  The first
time it is invoked, the eight tt(-match) functions will automatically
replace the builtin versions, so they do not need to be loaded explicitly.

The word styles available are as follows.  Only the first character
is examined.

startitem()
item(tt(bash))(
Word characters are alphanumeric characters only.
)
item(tt(normal))(
As in normal shell operation:  word characters are alphanumeric characters
plus any characters present in the string given by the parameter
tt($WORDCHARS).
)
item(tt(shell))(
Words are complete shell command arguments, possibly including complete
quoted strings, or any tokens special to the shell.
)
item(tt(whitespace))(
Words are any set of characters delimited by whitespace.
)
item(tt(default))(
Restore the default settings; this is usually the same as `tt(normal)'.
)
enditem()

More control can be obtained using the tt(zstyle) command, as described in
ifzman(zmanref(zshmodules))\
ifnzman(noderef(The zsh/zutil Module)).  Each style is looked up in the
context tt(:zle:)var(widget) where var(widget) is the name of the
user-defined widget, not the name of the function implementing it, so in
the case of the definitions supplied by tt(select-word-style) the
appropriate contexts are tt(:zle:forward-word), and so on.  The function
tt(select-word-style) itself always defines styles for the context
`tt(:zle:*)' which can be overridden by more specific (longer) patterns as
well as explicit contexts.

The style tt(word-style) specifies the rules to use.  This may have the
following values.

startitem()
item(tt(normal))(
Use the standard shell rules, i.e. alphanumerics and tt($WORDCHARS), unless
overridden by the styles tt(word-chars) or tt(word-class).
)
item(tt(specified))(
Similar to tt(normal), but em(only) the specified characters, and not also
alphanumerics, are considered word characters.
)
item(tt(unspecified))(
The negation of specified.  The given characters are those which will
em(not) be considered part of a word.
)
item(tt(shell))(
Words are obtained by using the syntactic rules for generating shell
command arguments.  In addition, special tokens which are never command
arguments such as `tt(())' are also treated as words.
)
item(tt(whitespace))(
Words are whitespace-delimited strings of characters.
)
enditem()

The first three of those styles usually use tt($WORDCHARS), but the value
in the parameter can be overridden by the style tt(word-chars), which works
in exactly the same way as tt($WORDCHARS).  In addition, the style
tt(word-class) uses character class syntax to group characters and takes
precedence over tt(word-chars) if both are set.  The tt(word-class) style
does not include the surrounding brackets of the character class; for
example, `tt(-:[:alnum:])' is a valid tt(word-class) to include all
alphanumerics plus the characters `tt(-)' and `tt(:)'.  Be careful
including `tt(])', `tt(^)' and `tt(-)' as these are special inside
character classes.

The final style is tt(skip-chars).  This is mostly useful for
tt(transpose-words) and similar functions.  If set, it gives a count of
characters starting at the cursor position which will not be considered
part of the word and are treated as space, regardless of what they actually
are.  For example, if

example(zstyle ':zle:transpose-words' skip-chars 1)

has been set, and tt(transpose-words-match) is called with the cursor on
the var(X) of tt(foo)var(X)tt(bar), where var(X) can be any character, then
the resulting expression is tt(bar)var(X)tt(foo).

Here are some examples of use of the styles, actually taken from the
simplified interface in tt(select-word-style):

example(zstyle ':zle:*' word-style standard
zstyle ':zle:*' word-chars '')

Implements bash-style word handling for all widgets, i.e. only
alphanumerics are word characters; equivalent to setting
the parameter tt(WORDCHARS) empty for the given context.

example(style ':zle:*kill*' word-style space)

Uses space-delimited words for widgets with the word `kill' in the name.
Neither of the styles tt(word-chars) nor tt(word-class) is used in this case.

The word matching and all the handling of tt(zstyle) settings is actually
implemented by the function tt(match-words-by-style).  This can be used to
create new user-defined widgets.  The calling function should set the local
parameter tt(curcontext) to tt(:zle:)var(widget), create the local
parameter tt(matched_words) and call tt(match-words-by-style) with no
arguments.  On return, tt(matched_words) will be set to an array with the
elements: (1) the start of the line (2) the word before the cursor (3) any
non-word characters between that word and the cursor (4) any non-word
character at the cursor position plus any remaining non-word characters
before the next word, including all characters specified by the
tt(skip-chars) style, (5) the word at or following the cursor (6) any
non-word characters following that word (7) the remainder of the line.  Any
of the elements may be an empty string; the calling function should test
for this to decide whether it can perform its function.

It is possible to pass options with arguments to tt(match-words-by-style)
to override the use of styles.  The options are:
startsitem()
sitem(tt(-w))(var(word-style))
sitem(tt(-s))(var(skip-chars))
sitem(tt(-c))(var(word-class))
sitem(tt(-C))(var(word-chars))
endsitem()

For example, tt(match-words-by-style -w shell -c 0) may be used to
extract the command argument around the cursor.
)
tindex(delete-whole-word-match)
item(tt(delete-whole-word-match))(
This is another function which works like the tt(-match) functions
described immediately above, i.e. using styles to decide the word
boundaries.  However, it is not a replacement for any existing function.

The basic behaviour is to delete the word around the cursor.  There is no
numeric prefix handling; only the single word around the cursor is
considered.  If the widget contains the string tt(kill), the removed text
will be placed in the cutbuffer for future yanking.  This can be obtained
by defining tt(kill-whole-word-match) as follows:

example(zle -N kill-whole-word-match delete-whole-word-match)

and then binding the widget tt(kill-whole-word-match).
)
tindex(copy-earlier-word)
item(tt(copy-earlier-word))(
This widget works like a combination of tt(insert-last-word) and
tt(copy-prev-shell-word).  Repeated invocations of the widget retrieve
earlier words on the relevant history line.  With a numeric argument
var(N), insert the var(N)th word from the history line; var(N) may be
negative to count from the end of the line.

If tt(insert-last-word) has been used to retrieve the last word on a
previous history line, repeated invocations will replace that word with
earlier words from the same line.

Otherwise, the widget applies to words on the line currently being edited.
The tt(widget) style can be set to the name of another widget that should
be called to retrieve words.  This widget must accept the same three
arguments as tt(insert-last-word).
)
tindex(cycle-completion-positions)
item(tt(cycle-completion-positions))(
After inserting an unambiguous string into the command line, the new
function based completion system may know about multiple places in
this string where characters are missing or differ from at least one
of the possible matches.  It will then place the cursor on the
position it considers to be the most interesting one, i.e. the one
where one can disambiguate between as many matches as possible with as 
little typing as possible.

This widget allows the cursor to be easily moved to the other interesting
spots.  It can be invoked repeatedly to cycle between all positions
reported by the completion system.
)
tindex(edit-command-line)
item(tt(edit-command-line))(
Edit the command line using your visual editor, as in tt(ksh).

example(bindkey -M vicmd v edit-command-line)
)
tindex(history-beginning-search-backward-end)
tindex(history-beginning-search-forward-end)
item(tt(history-search-end))(
This function implements the widgets
tt(history-beginning-search-backward-end) and
tt(history-beginning-search-forward-end).  These commands work by first
calling the corresponding builtin widget (see
ifzman(`History Control' in zmanref(zshzle))\
ifnzman(noderef(History Control))\
) and then moving the cursor to the end of the line.  The original cursor
position is remembered and restored before calling the builtin widget a
second time, so that the same search is repeated to look farther through
the history.

Although you tt(autoload) only one function, the commands to use it are
slightly different because it implements two widgets.

example(zle -N history-beginning-search-backward-end \ 
       history-search-end
zle -N history-beginning-search-forward-end \ 
       history-search-end
bindkey '\e^P' history-beginning-search-backward-end
bindkey '\e^N' history-beginning-search-forward-end)
)
tindex(history-pattern-search)
tindex(history-pattern-search-backward)
tindex(history-pattern-search-forward)
item(tt(history-pattern-search))(
The function tt(history-pattern-search) implements widgets which prompt
for a pattern with which to search the history backwards or forwards.  The
pattern is in the usual zsh format, however the first character may be
tt(^) to anchor the search to the start of the line, and the last character
may be tt($) to anchor the search to the end of the line.  If the
search was not anchored to the end of the line the cursor is positioned
just after the pattern found.

The commands to create bindable widgets are similar to those in the
example immediately above:

example(autoload -U history-pattern-search
zle -N history-pattern-search-backward history-pattern-search
zle -N history-pattern-search-forward history-pattern-search)
)
tindex(up-line-or-beginning-search)
tindex(down-line-or-beginning-search)
item(tt(up-line-or-beginning-search), tt(down-line-or-beginning-search))(
These widgets are similar to the builtin functions tt(up-line-or-search)
and tt(down-line-or-search):  if in a multiline buffer they move up or
down within the buffer, otherwise they search for a history line matching
the start of the current line.  In this case, however, they search for
a line which matches the current line up to the current cursor position, in
the manner of tt(history-beginning-search-backward) and tt(-forward), rather
than the first word on the line.
)
tindex(incarg)
vindex(incarg, use of)
item(tt(incarg))(
Typing the keystrokes for this widget with the cursor placed on or to the
left of an integer causes that integer to be incremented by one.  With a
numeric prefix argument, the number is incremented by the amount of the
argument (decremented if the prefix argument is negative).  The shell
parameter tt(incarg) may be set to change the default increment to
something other than one.

example(bindkey '^X+' incarg)
)
tindex(incremental-complete-word)
item(tt(incremental-complete-word))(
This allows incremental completion of a word.  After starting this
command, a list of completion choices can be shown after every character
you type, which you can delete with tt(^H) or tt(DEL).  Pressing return
accepts the completion so far and returns you to normal editing (that is,
the command line is em(not) immediately executed).  You can hit tt(TAB) to
do normal completion, tt(^G) to abort back to the state when you started,
and tt(^D) to list the matches.

This works only with the new function based completion system.

example(bindkey '^Xi' incremental-complete-word)
)
tindex(insert-composed-char)
item(tt(insert-composed-char))(
This function allows you to compose characters that don't appear on the
keyboard to be inserted into the command line.  The command is followed by
two keys corresponding to ASCII characters (there is no prompt).  For
accented characters, the two keys are a base character followed by a code
for the accent, while for other special characters the two characters
together form a mnemonic for the character to be inserted.  The
two-character codes are a subset of those given by RFC 1345 (see for
example tt(http://www.faqs.org/rfcs/rfc1345.html)).

For best results zsh should have been built with support for multibyte
characters (configured with tt(--enable-multibyte)); however, the function
works for the limited range of characters available in single-byte
character sets such as ISO-8859-1.

The character is converted into the local representation and
inserted into the command line at the cursor position.
(The conversion is done within the shell, using whatever facilities
the C library provides.)  With a numeric argument, the character and its
code are previewed in the status line

The function may be run outside zle in which case it prints the character
(together with a newline) to standard output.  Input is still read from
keystrokes.

The set of accented characters is reasonably complete up to Unicode
character U+0180, the set of special characters less so.  However, it it
is very sporadic from that point.  Adding new characters is easy,
however; see the function tt(define-composed-chars).  Please send any
additions to tt(zsh-workers@sunsite.dk).

The codes for the second character when used to accent the first are as
follows.  Note that not every character can take every accent.
startsitem()
sitem(tt(!))(Grave.)
sitem(tt(RQUOTE()))(Acute.)
sitem(tt(>))(Circumflex.)
sitem(tt(?))(Tilde.  (This is not tt(~) as RFC 1345 does not assume that
character is present on the keyboard.))
sitem(tt(-))(Macron.  (A horizonal bar over the base character.))
sitem(tt(LPAR()))(Breve.  (A shallow dish shape over the base character.))
sitem(tt(.))(Dot above the base character, or in the case of tt(i) no dot,
or in the case of tt(L) and tt(l) a centered dot.)
sitem(tt(:))(Diaeresis (Umlaut).)
sitem(tt(c))(Cedilla.)
sitem(tt(_))(Underline, however there are currently no underlined characters.)
sitem(tt(/))(Stroke through the base character.)
sitem(tt("))(Double acute (only supported on a few letters).)
sitem(tt(;))(Ogonek.  (A little forward facing hook at the bottom right
of the character.))
sitem(tt(<))(Caron.  (A little v over the letter.))
sitem(tt(0))(Circle over the base character.)
sitem(tt(2))(Hook over the base character.)
sitem(tt(9))(Horn over the base character.)
endsitem()

The most common characters from the Arabic, Cyrillic, Greek and Hebrew
alphabets are available; consult RFC 1345 for the appropriate sequences.
In addition, a set of two letter codes not in RFC 1345 are available for
the double-width characters corresponding to ASCII characters from tt(!)
to tt(~) (0x21 to 0x7e) by preceeding the character with tt(^), for
example tt(^A) for a double-width tt(A).

The following other two-character sequences are understood.

startitem()
item(ASCII characters)(
These are already present on most keyboards:
startsitem()
sitem(tt(<LPAR()))(Left square bracket)
sitem(tt(//))(Backslash (solidus))
sitem(tt(RPAR()>))(Right square bracket)
sitem(tt(LPAR()!))(Left brace (curly bracket))
sitem(tt(!!))(Vertical bar (pipe symbol))
sitem(tt(!RPAR()))(Right brace (curly bracket))
sitem(tt(RQUOTE()?))(Tilde)
endsitem()
)
item(Special letters)(
Characters found in various variants of the Latin alphabet:
startsitem()
sitem(tt(ss))(Eszett (scafes S))
sitem(tt(D-), tt(d-))(Eth)
sitem(tt(TH), tt(th))(Thorn)
sitem(tt(kk))(Kra)
sitem(tt(RQUOTE()n))(RQUOTE()n)
sitem(tt(NG), tt(ng))(Ng)
sitem(tt(OI), tt(oi))(Oi)
sitem(tt(yr))(yr)
sitem(tt(ED))(ezh)
endsitem()
)
item(Currency symbols)(
startsitem()
sitem(tt(Ct))(Cent)
sitem(tt(Pd))(Pound sterling (also lira and others))
sitem(tt(Cu))(Currency)
sitem(tt(Ye))(Yen)
sitem(tt(Eu))(Euro (N.B. not in RFC 1345))
endsitem()
)
item(Punctuation characters)(
References to "right" quotes indicate the shape (like a 9 rather than 6)
rather than their grammatical use.  (For example, a "right" low double
quote is used to open quotations in German.)
startsitem()
sitem(tt(!I))(Inverted exclamation mark)
sitem(tt(BB))(Broken vertical bar)
sitem(tt(SE))(Section)
sitem(tt(Co))(Copyright)
sitem(tt(-a))(Spanish feminine ordinal indicator)
sitem(tt(<<))(Left guillemet)
sitem(tt(--))(Soft hyphen)
sitem(tt(Rg))(Registered trade mark)
sitem(tt(PI))(Pilcrow (paragraph))
sitem(tt(-o))(Spanish masculine ordinal indicator)
sitem(tt(>>))(Right guillemet)
sitem(tt(?I))(Inverted question mark)
sitem(tt(-1))(Hyphen)
sitem(tt(-N))(En dash)
sitem(tt(-M))(Em dash)
sitem(tt(-3))(Horizontal bar)
sitem(tt(:3))(Vertical ellipsis)
sitem(tt(.3))(Horizontal midline ellipsis)
sitem(tt(!2))(Double vertical line)
sitem(tt(=2))(Double low line)
sitem(tt(RQUOTE()6))(Left single quote)
sitem(tt(RQUOTE()9))(Right single quote)
sitem(tt(.9))("Right" low quote)
sitem(tt(9+RQUOTE()))(Reversed "right" quote)
sitem(tt("6))(Left double quote)
sitem(tt("9))(Right double quote)
sitem(tt(:9))("Right" low double quote)
sitem(tt(9"))(Reversed "right" double quote)
sitem(tt(/-))(Dagger)
sitem(tt(/=))(Double dagger)
endsitem()
)
item(Mathematical symbols)(
startsitem()
sitem(tt(DG))(Degree)
sitem(tt(-2), tt(+-), tt(-+))(- sign, +/- sign, -/+ sign)
sitem(tt(2S))(Superscript 2)
sitem(tt(3S))(Superscript 3)
sitem(tt(1S))(Superscript 1)
sitem(tt(My))(Micro)
sitem(tt(.M))(Middle dot)
sitem(tt(14))(Quarter)
sitem(tt(12))(Half)
sitem(tt(34))(Three quarters)
sitem(tt(*X))(Multiplication)
sitem(tt(-:))(Division)
sitem(tt(%0))(Per mille)
sitem(tt(FA), tt(TE), tt(/0))(For all, there exists, empty set)
sitem(tt(dP), tt(DE), tt(NB))(Partial derivative, delta (increment), del
(nabla))
sitem(tt(LPAR()-), tt(-RPAR()))(Element of, contains)
sitem(tt(*P), tt(+Z))(Product, sum)
sitem(tt(*-), tt(Ob), tt(Sb))(Asterisk, ring, bullet)
sitem(tt(RT), tt(0+LPAR()), tt(00))(Root sign, proportional to, infinity)
endsitem()
)
item(Other symbols)(
startsitem()
sitem(tt(cS), tt(cH), tt(cD), tt(cC))(Card suits: spades, hearts, diamonds,
clubs)
sitem(tt(Md), tt(M8), tt(M2), tt(Mb), tt(Mx), tt(MX))(Musical notation:
crotchet (quarter note), quaver (eighth note), semiquavers (sixteenth
notes), flag sign, natural signa, sharp sign)
sitem(tt(Fm), tt(Ml))(Female, male)
endsitem()
)
item(Accents on their own)(
startsitem()
sitem(tt(RQUOTE()>))(Circumflex (same as caret, tt(^)))
sitem(tt(RQUOTE()!))(Grave (same as backtick, tt(`)))
sitem(tt(RQUOTE(),))(Cedilla)
sitem(tt(RQUOTE():))(Diaeresis (Umlaut))
sitem(tt(RQUOTE()m))(Macron)
sitem(tt(RQUOTE()RQUOTE()))(Acute)
endsitem()
)
enditem()
)
tindex(insert-files)
item(tt(insert-files))(
This function allows you type a file pattern, and see the results of the
expansion at each step.  When you hit return, all expansions are inserted
into the command line.

example(bindkey '^Xf' insert-files)
)
tindex(narrow-to-region)
tindex(narrow-to-region-invisible)
xitem(tt(narrow-to-region [ -p) var(pre) tt(] [ -P) var(post) tt(]))
xitem(    tt([ -S) var(statepm) tt(| -R) var(statepm) tt(] [ -n ] [) var(start) var(end) tt(])))
item(tt(narrow-to-region-invisible))(
Narrow the editable portion of the buffer to the region between the cursor
and the mark, which may be in either order.  The region may not be empty.

tt(narrow-to-region) may be used as a widget or called as a function from a
user-defined widget; by default, the text outside the editable area remains
visible.  A tt(recursive-edit) is performed and the original widening
status is then restored.  Various options and arguments are available when
it is called as a function.

The options tt(-p) var(pretext) and tt(-P) var(posttext) may be
used to replace the text before and after the display for the duration of
the function; either or both may be an empty string.

If the option tt(-n) is also given, var(pretext) or var(posttext) will only
be inserted if there is text before or after the region respectively which
will be made invisible.

Two numeric arguments may be given which will be used instead of the cursor
and mark positions.

The option tt(-S) var(statepm) is used to narrow according to the other
options while saving the original state in the parameter with name
var(statepm), while the option tt(-R) var(statepm) is used to restore the
state from the parameter; note in both cases the em(name) of the parameter
is required.  In the second case, other options and arguments are
irrelevant.  When this method is used, no tt(recursive-edit) is performed;
the calling widget should call this function with the option tt(-S),
perform its own editing on the command line or pass control to the user
via `tt(zle recursive-edit)', then call this function with the option
tt(-R).  The argument var(statepm) must be a suitable name for an ordinary
parameter, except that parameters beginning with the prefix tt(_ntr_) are
reserved for use within tt(narrow-to-region).  Typically the parameter will
be local to the calling function.

tt(narrow-to-region-invisible) is a simple widget which calls
tt(narrow-to-region) with arguments which replace any text outside the
region with `tt(...)'.

The display is restored (and the widget returns) upon any zle command
which would usually cause the line to be accepted or aborted.  Hence an
additional such command is required to accept or abort the current line.

The return status of both widgets is zero if the line was accepted, else
non-zero.

Here is a trivial example of a widget using this feature.
example(local state
narrow-to-region -p $'Editing restricted region\n' \ 
  -P '' -S state
zle recursive-edit
narrow-to-region -R state)
)
tindex(predict-on)
tindex(predict-off)
item(tt(predict-on))(
This set of functions implements predictive typing using history search.
After tt(predict-on), typing characters causes the editor to look backward
in the history for the first line beginning with what you have typed so
far.  After tt(predict-off), editing returns to normal for the line found.
In fact, you often don't even need to use tt(predict-off), because if the
line doesn't match something in the history, adding a key performs
standard completion, and then inserts itself if no completions were found.
However, editing in the middle of a line is liable to confuse prediction;
see the tt(toggle) style below.

With the function based completion system (which is needed for this), you
should be able to type tt(TAB) at almost any point to advance the cursor
to the next ``interesting'' character position (usually the end of the
current word, but sometimes somewhere in the middle of the word).  And of
course as soon as the entire line is what you want, you can accept with
return, without needing to move the cursor to the end first.

The first time tt(predict-on) is used, it creates several additional
widget functions:

startsitem()
sitem(tt(delete-backward-and-predict))(Replaces the tt(backward-delete-char)
widget.  You do not need to bind this yourself.)
sitem(tt(insert-and-predict))(Implements predictive typing by replacing the
tt(self-insert) widget.  You do not need to bind this yourself.)
sitem(tt(predict-off))(Turns off predictive typing.)
endsitem()

Although you tt(autoload) only the tt(predict-on) function, it is
necessary to create a keybinding for tt(predict-off) as well.

example(zle -N predict-on
zle -N predict-off
bindkey '^X^Z' predict-on
bindkey '^Z' predict-off)
)
tindex(read-from-minibuffer)
item(tt(read-from-minibuffer))(
This is most useful when called as a function from inside a widget, but will
work correctly as a widget in its own right.  It prompts for a value
below the current command line; a value may be input using all of the
standard zle operations (and not merely the restricted set available
when executing, for example, tt(execute-named-cmd)).  The value is then
returned to the calling function in the parameter tt($REPLY) and the
editing buffer restored to its previous state.  If the read was aborted
by a keyboard break (typically tt(^G)), the function returns status 1
and tt($REPLY) is not set.

If one argument is supplied to the function it is taken as a prompt,
otherwise `tt(? )' is used.  If two arguments are supplied, they are the
prompt and the initial value of tt($LBUFFER), and if a third argument is
given it is the initial value of tt($RBUFFER).  This provides a default
value and starting cursor placement.  Upon return the entire buffer is the
value of tt($REPLY).

One option is available: `tt(-k) var(num)' specifies that var(num)
characters are to be read instead of a whole line.  The line editor is not
invoked recursively in this case, so depending on the terminal settings
the input may not be visible, and only the input keys are placed in
tt($REPLY), not the entire buffer.  Note that unlike the tt(read) builtin
var(num) must be given; there is no default.

The name is a slight misnomer, as in fact the shell's own minibuffer is
not used.  Hence it is still possible to call tt(executed-named-cmd) and
similar functions while reading a value.
)
tindex(replace-string)
tindex(replace-pattern)
item(tt(replace-string), tt(replace-pattern))(
The function tt(replace-string) implements two widgets.
If defined under the same name as the function, it prompts for two
strings; the first (source) string will be replaced by the second
everywhere it occurs in the line editing buffer.

If the widget name contains the word `tt(pattern)', for example by
defining the widget using the command `tt(zle -N replace-pattern
replace-string)', then the replacement is done by pattern matching.  All
zsh extended globbing patterns can be used in the source string; note
that unlike filename generation the pattern does not need to match an
entire word, nor do glob qualifiers have any effect.  In addition, the
replacement string can contain parameter or command substitutions.
Furthermore, a `tt(&)' in the replacement string will be replaced with
the matched source string, and a backquoted digit `tt(\)var(N)' will be
replaced by the var(N)th parenthesised expression matched.  The form
`tt(\{)var(N)tt(})' may be used to protect the digit from following
digits.

By default the previous source or replacement string will not be offered
for editing.  However, this feature can be activated by setting the style
tt(edit-previous) in the context tt(:zle:)var(widget) (for example,
tt(:zle:replace-string)) to tt(true).  In addition, a positive
numeric argument forces the previous values to be offered, a negative or
zero argument forces them not to be.

For example, starting from the line:

example(print This line contains fan and fond)

and invoking tt(replace-pattern) with the source string `tt(f(?)n)' and
the replacment string `tt(c\1r)' produces the not very useful line:

example(print This line contains car and cord)

The range of the replacement string can be limited by using the
tt(narrow-to-region-invisible) widget.  One limitation of the current
version is that tt(undo) will cycle through changes to the replacement
and source strings before undoing the replacement itself.
)
tindex(smart-insert-last-word)
item(tt(smart-insert-last-word))(
This function may replace the tt(insert-last-word) widget, like so:

example(zle -N insert-last-word smart-insert-last-word)

With a numeric prefix, or when passed command line arguments in a call
from another widget, it behaves like tt(insert-last-word), except that
words in comments are ignored when tt(INTERACTIVE_COMMENTS) is set.

Otherwise, the rightmost ``interesting'' word from the previous command is
found and inserted.  The default definition of ``interesting'' is that the
word contains at least one alphabetic character, slash, or backslash.
This definition may be overridden by use of the tt(match) style.  The
context used to look up the style is the widget name, so usually the
context is tt(:insert-last-word).  However, you can bind this function to
different widgets to use different patterns:

example(zle -N insert-last-assignment smart-insert-last-word
zstyle :insert-last-assignment match '[[:alpha:]][][[:alnum:]]#=*'
bindkey '\e=' insert-last-assignment)
)
tindex(which-command)
item(tt(which-command))(
This function is a drop-in replacement for the builtin widget
tt(which-command).  It has enhanced behaviour, in that it correctly
detects whether or not the command word needs to be expanded as an
alias; if so, it continues tracing the command word from the expanded
alias until it reaches the command that will be executed.

The style tt(whence) is available in the context tt(:zle:$WIDGET); this
may be set to an array to give the command and options that will be used to
investigate the command word found.  The default is tt(whence -c).
)
enditem()

subsect(Styles)

The behavior of several of the above widgets can be controlled by the use
of the tt(zstyle) mechanism.  In particular, widgets that interact with
the completion system pass along their context to any completions that
they invoke.

startitem()
kindex(break-keys, widget style)
item(tt(break-keys))(
This style is used by the tt(incremental-complete-word) widget. Its value
should be a pattern, and all keys matching this pattern will cause the
widget to stop incremental completion without the key having any further
effect. Like all styles used directly by
tt(incremental-complete-word), this style is looked up using the
context `tt(:incremental)'.
)
kindex(completer, completion style)
item(tt(completer))(
The tt(incremental-complete-word) and tt(insert-and-predict) widgets set
up their top-level context name before calling completion.  This allows
one to define different sets of completer functions for normal completion
and for these widgets.  For example, to use completion, approximation and
correction for normal completion, completion and correction for
incremental completion and only completion for prediction one could use:

example(zstyle ':completion:*' completer \ 
        _complete _correct _approximate
zstyle ':completion:incremental:*' completer \ 
        _complete _correct
zstyle ':completion:predict:*' completer \ 
        _complete)

It is a good idea to restrict the completers used in prediction, because
they may be automatically invoked as you type.  The tt(_list) and
tt(_menu) completers should never be used with prediction.  The
tt(_approximate), tt(_correct), tt(_expand), and tt(_match) completers may
be used, but be aware that they may change characters anywhere in the word
behind the cursor, so you need to watch carefully that the result is what
you intended.
)
kindex(cursor, completion style)
item(tt(cursor))(
The tt(insert-and-predict) widget uses this style, in the context
`tt(:predict)', to decide where to place the cursor after completion has
been tried.  Values are:

startitem()
item(tt(complete))(
The cursor is left where it was when completion finished, but only if
it is after a character equal to the one just inserted by the user.  If 
it is after another character, this value is the same as `tt(key)'.
)
item(tt(key))(
The cursor is left
after the var(n)th occurrence of the character just inserted, where
var(n) is the number of times that character appeared in the word
before completion was attempted.  In short, this has the effect of
leaving the cursor after the character just typed even if the
completion code found out that no other characters need to be inserted 
at that position.
)
enditem()

Any other value for this style unconditionally leaves the cursor at the
position where the completion code left it.
)
kindex(list, widget style)
item(tt(list))(
When using the tt(incremental-complete-word) widget, this style says
if the matches should be listed on every key press (if they fit on the 
screen).  Use the context prefix `tt(:completion:incremental)'.

The tt(insert-and-predict) widget uses this style to decide if the
completion should be shown even if there is only one possible completion.
This is done if the value of this style is the string tt(always).  In this
case the context is `tt(:predict)' (em(not) `tt(:completion:predict)').
)
kindex(match, widget style)
item(tt(match))(
This style is used by tt(smart-insert-last-word) to provide a pattern
(using full tt(EXTENDED_GLOB) syntax) that matches an interesting word.
The context is the name of the widget to which tt(smart-insert-last-word)
is bound (see above).  The default behavior of tt(smart-insert-last-word)
is equivalent to:

example(zstyle :insert-last-word match '*[[:alpha:]/\\]*')

However, you might want to include words that contain spaces:

example(zstyle :insert-last-word match '*[[:alpha:][:space:]/\\]*')

Or include numbers as long as the word is at least two characters long:

example(zstyle :insert-last-word match '*([[:digit:]]?|[[:alpha:]/\\])*')

The above example causes redirections like "2>" to be included.
)
kindex(prompt, widget style)
item(tt(prompt))(
The tt(incremental-complete-word) widget shows the value of this
style in the status line during incremental completion.  The string
value may contain any of the following substrings in the manner of
the tt(PS1) and other prompt parameters:

startitem()
item(tt(%c))(
Replaced by the name of the completer function that generated the
matches (without the leading underscore).
)
item(tt(%l))(
When the tt(list) style is set,
replaced by `tt(...)' if the list of matches is too long to fit on the
screen and with an empty string otherwise.  If the tt(list) style is
`false' or not set, `tt(%l)' is always removed.
)
item(tt(%n))(
Replaced by the number of matches generated.
)
item(tt(%s))(
Replaced by `tt(-no match-)', `tt(-no prefix-)', or an empty string
if there is no completion matching the word on the line, if the
matches have no common prefix different from the word on the line, or
if there is such a common prefix, respectively.
)
item(tt(%u))(
Replaced by the unambiguous part of all matches, if there
is any, and if it is different from the word on the line.
)
enditem()

Like `tt(break-keys)', this uses the `tt(:incremental)' context.
)
kindex(stop-keys, widget style)
item(tt(stop-keys))(
This style is used by the tt(incremental-complete-word) widget.  Its value
is treated similarly to the one for the tt(break-keys) style (and uses 
the same context: `tt(:incremental)').  However, in
this case all keys matching the pattern given as its value will stop
incremental completion and will then execute their usual function.
)
kindex(toggle, widget style)
item(tt(toggle))(
This boolean style is used by tt(predict-on) and its related widgets in
the context `tt(:predict)'.  If set to one of the standard `true' values,
predictive typing is automatically toggled off in situations where it is
unlikely to be useful, such as when editing a multi-line buffer or after
moving into the middle of a line and then deleting a character.  The
default is to leave prediction turned on until an explicit call to
tt(predict-off).
)
kindex(verbose, widget style)
item(tt(verbose))(
This boolean style is used by tt(predict-on) and its related widgets in
the context `tt(:predict)'.  If set to one of the standard `true' values,
these widgets display a message below the prompt when the predictive state
is toggled.  This is most useful in combination with the tt(toggle) style.
The default does not display these messages.
)
kindex(widget, widget style)
item(tt(widget))(
This style is similar to the tt(command) style: For widget functions that
use tt(zle) to call other widgets, this style can sometimes be used to
override the widget which is called.  The context for this style is the
name of the calling widget (em(not) the name of the calling function,
because one function may be bound to multiple widget names).

example(zstyle :copy-earlier-word widget smart-insert-last-word)

Check the documentation for the calling widget or function to determine
whether the tt(widget) style is used.
)
enditem()

texinode(Exception Handling)(MIME Functions)(ZLE Functions)(User Contributions)
sect(Exception Handling)

Two functions are provided to enable zsh to provide exception handling in a
form that should be familiar from other languages.

startitem()
findex(throw)
item(tt(throw) var(exception))(
The function tt(throw) throws the named var(exception).  The name is
an arbitrary string and is only used by the tt(throw) and tt(catch)
functions.  An exception is for the most part treated the same as a
shell error, i.e. an unhandled exception will cause the shell to abort all
processing in a function or script and to return to the top level in an
interactive shell.
)
item(tt(catch) var(exception-pattern))(
The function tt(catch) returns status zero if an exception was thrown and
the pattern var(exception-pattern) matches its name.  Otherwise it
returns status 1.  var(exception-pattern) is a standard
shell pattern, respecting the current setting of the tt(EXTENDED_GLOB)
option.  An alias tt(catch) is also defined to prevent the argument to the
function from matching filenames, so patterns may be used unquoted.  Note
that as exceptions are not fundamentally different from other shell errors
it is possible to catch shell errors by using an empty string as the
exception name.  The shell variable tt(CAUGHT) is set by tt(catch) to the
name of the exception caught.  It is possible to rethrow an exception by
calling the tt(throw) function again once an exception has been caught.
findex(catch)
)
enditem()

The functions are designed to be used together with the tt(always) construct
described in
ifzman(zmanref(zshmisc))\
ifnzman(noderef(Complex Commands)).  This is important as only this
construct provides the required support for exceptions.  A typical example
is as follows.

example({
  # "try" block
  # ... nested code here calls "throw MyExcept"
} always {
  # "always" block
  if catch MyExcept; then
    print "Caught exception MyExcept"
  elif catch ''; then
    print "Caught a shell error.  Propagating..."
    throw ''
  fi
  # Other exceptions are not handled but may be caught further
  # up the call stack.
})

If all exceptions should be caught, the following idiom might be
preferable.

example({
  # ... nested code here throws an exception
} always {
  if catch *; then
    case $CAUGHT in
      LPAR()MyExcept+RPAR()
      print "Caught my own exception"
      ;;
      LPAR()*RPAR()
      print "Caught some other exception"
      ;;
    esac
  fi
})

In common with exception handling in other languages, the exception may be
thrown by code deeply nested inside the `try' block.  However, note that it
must be thrown inside the current shell, not in a subshell forked for a
pipeline, parenthesised current-shell construct, or some form of
command or process substitution.

The system internally uses the shell variable tt(EXCEPTION) to record the
name of the exception between throwing and catching.  One drawback of this
scheme is that if the exception is not handled the variable tt(EXCEPTION)
remains set and may be incorrectly recognised as the name of an exception
if a shell error subsequently occurs.  Adding tt(unset EXCEPTION) at the
start of the outermost layer of any code that uses exception handling will
eliminate this problem.

texinode(MIME Functions)(Other Functions)(Exception Handling)(User Contributions)
sect(MIME Functions)

Three functions are available to provide handling of files recognised by
extension, for example to dispatch a file tt(text.ps) when executed as a
command to an appropriate viewer.

startitem()
xitem(tt(zsh-mime-setup [-flv]))
item(tt(zsh-mime-handler))(
These two functions use the files tt(~/.mime.types) and tt(/etc/mime.types),
which associate types and extensions, as well as tt(~/.mailcap) and
tt(/etc/mailcap) files, which associate types and the programs that
handle them.  These are provided on many systems with the Multimedia
Internet Mail Extensions.

To enable the system, the function tt(zsh-mime-setup) should be
autoloaded and run.  This allows files with extensions to be treated
as executable; such files be completed by the function completion system.
The function tt(zsh-mime-handler) should not need to be called by the
user.

The system works by setting up suffix aliases with `tt(alias -s)'.
Suffix aliases already installed by the user will not be overwritten.

Repeated calls to tt(zsh-mime-setup) do not override the existing
mapping between suffixes and executable files unless the option tt(-f)
is given.  Note, however, that this does not override existing suffix
aliases assigned to handlers other than tt(zsh-mime-handler).
Calling tt(zsh-mime-setup) with the option tt(-l) lists the existing
mappings without altering them.  Calling tt(zsh-mime-setup) with the option
tt(-v) causes verbose output to be shown during the setup operation.

The system respects the tt(mailcap) flags tt(needsterminal) and
tt(copiousoutput), see manref(mailcap)(4).

The functions use the following styles, which are defined with the
tt(zstyle) builtin command (\
ifzman(see zmanref(zshmodules))\
ifnzman(noderef(The zsh/zutil Module))).  They should be defined
before tt(zsh-mime-setup) is run.  The contexts used all
start with tt(:mime:), with additional components in some cases.
It is recommended that a trailing tt(*) (suitably quoted) be appended
to style patterns in case the system is extended in future.  Some
examples are given below.
startitem()
item(mime-types)(
A list of files in the format of tt(~/.mime.types) and
tt(/etc/mime.types) to be read during setup, replacing the default list
which consists of those two files.  The context is tt(:mime:).
A tt(PLUS()) in the list will be replaced by the default files.
)
item(mailcap)(
A list of files in the format of tt(~/.mailcap) and
tt(/etc/mailcap) to be read during setup, replacing the default list
which consists of those two files.  The context is tt(:mime:).
A tt(PLUS()) in the list will be replaced by the default files.
)
item(handler)(
Specifies a handler for a suffix; the suffix is given by the context as
tt(:mime:.)var(suffix)tt(:), and the format of the handler is exactly
that in tt(mailcap).  Note in particular the `tt(.)' and trailing colon
to distinguish this use of the context.  This overrides any handler
specified by the tt(mailcap) files.  If the handler requires a terminal,
the tt(flags) style should be set to include the word tt(needsterminal),
or if the output is to be displayed through a pager (but not if the
handler is itself a pager), it should include tt(copiousoutput).
)
item(flags)(
Defines flags to go with a handler; the context is as for the
tt(handler) style, and the format is as for the flags in tt(mailcap).
)
item(pager)(
If set, will be used instead of tt($PAGER) or tt(more) to handle
suffixes where the tt(copiousoutput) flag is set.  The context is
as for tt(handler), i.e. tt(:mime:.)var(suffix)tt(:) for handling
a file with the given var(suffix).
)
enditem()

Examples:

example(zstyle ':mime:*' mailcap ~/.mailcap /usr/local/etc/mailcap
zstyle ':mime:.txt:' handler less %s
zstyle ':mime:.txt:' flags needsterminal)

When tt(zsh-mime-setup) is subsequently run, it will look for
tt(mailcap) entries in the two files given.  Files of suffix tt(.txt)
will be handled by running `tt(less) var(file.txt)'.  The flag
tt(needsterminal) is set to show that this program must run attached to a
terminal.

As there are several steps to dispatching a command, the following
should be checked if attempting to execute a file by extension
tt(.)var(ext) does not have the expected effect.

startitem()
item()(
The command `tt(alias -s) var(ext)' should show
`tt(ps=zsh-mime-handler)'.  If it shows something else, another suffix
alias was already installed and was not overwritten.  If it shows
nothing, no handler was installed:  this is most likely because no
handler was found in the tt(.mime.types) and tt(mailcap) combination for
tt(.ext) files.  In that case, appropriate handling should be added to
tt(~/.mime.types) and tt(mailcap).
)
item()(
If the extension is handled by tt(zsh-mime-handler) but the file is
not opened correctly, either the handler defined for the type is
incorrect, or the flags associated with it are in appropriate.  Running
tt(zsh-mime-setup -l) will show the handler and, if there are any, the
flags.  A tt(%s) in the handler is replaced by the file (suitably quoted
if necessary).  Check that the handler program listed lists and can
be run in the way shown.  Also check that the flags tt(needsterminal) or
tt(copiousoutput) are set if the handler needs to be run under a
terminal; the second flag is used if the output should be sent to a pager.
An example of a suitable tt(mailcap) entry for such a program is:

example(text/html; /usr/bin/lynx '%s'; needsterminal)
)
enditem()
)
item(tt(pick-web-browser))(
This function is separate from the two MIME functions described above
and can be assigned directly to a suffix:

example(autoload -U pick-web-browser
alias -s html=pick-web-browser)

It is provided as an intelligent front end to dispatch a web browser.
It will check if an X Windows display is available, and if so
if there is already a browser running which can accept a remote
connection.  In that case, the file will be displayed in that browser;
you should check explicitly if it has appeared in the running browser's
window.  Otherwise, it will start a new browser according to a builtin
set of preferences.

Alternatively, tt(pick-web-browser) can be run as a zsh script.

Two styles are available to customize the choice of browsers:
tt(x-browsers) when running under the X Windows System, and
tt(tty-browsers) otherwise.  These are arrays in decreasing order
of preference consiting of the command name under which to start the
browser.  They are looked up in the context tt(:mime:) (which may
be extended in future, so appending `tt(*)' is recommended).  For
example,

example(zstyle ':mime:*' x-browsers opera konqueror netscape)

specifies that tt(pick-web-browser) should first look for a runing
instance of Opera, Konqueror or Netscape, in that order, and if it
fails to find any should attempt to start Opera.
)
enditem()

texinode(Other Functions)()(MIME Functions)(User Contributions)
sect(Other Functions)

There are a large number of helpful functions in the tt(Functions/Misc)
directory of the zsh distribution.  Most are very simple and do not
require documentation here, but a few are worthy of special mention.

subsect(Descriptions)

startitem()
findex(colors)
item(tt(colors))(
This function initializes several associative arrays to map color names to
(and from) the ANSI standard eight-color terminal codes.  These are used
by the prompt theme system (ifzman(see above)\
ifnzman(noderef(Prompt Themes))).  You seldom should need to run
tt(colors) more than once.

The eight base colors are: black, red, green, yellow, blue, magenta, cyan,
and white.  Each of these has codes for foreground and background.  In
addition there are eight intensity attributes: bold, faint, standout,
underline, blink, reverse, and conceal.  Finally, there are six codes used
to negate attributes: none (reset all attributes to the defaults), normal
(neither bold nor faint), no-standout, no-underline, no-blink, and
no-reverse.

Some terminals do not support all combinations of colors and intensities.

The associative arrays are:

startitem()
xitem(color)
item(colour)(
Map all the color names to their integer codes, and integer codes to the
color names.  The eight base names map to the foreground color codes, as
do names prefixed with `tt(fg-)', such as `tt(fg-red)'.  Names prefixed
with `tt(bg-)', such as `tt(bg-blue)', refer to the background codes.  The
reverse mapping from code to color yields base name for foreground codes
and the tt(bg-) form for backgrounds.

Although it is a misnomer to call them `colors', these arrays also map the
other fourteen attributes from names to codes and codes to names.
)
xitem(fg)
xitem(fg_bold)
item(fg_no_bold)(
Map the eight basic color names to ANSI terminal escape sequences that set
the corresponding foreground text properties.  The tt(fg) sequences change
the color without changing the eight intensity attributes.
)
xitem(bg)
xitem(bg_bold)
item(bg_no_bold)(
Map the eight basic color names to ANSI terminal escape sequences that set
the corresponding background properties.  The tt(bg) sequences change the
color without changing the eight intensity attributes.
)
enditem()

In addition, the scalar parameters tt(reset_color) and tt(bold_color) are
set to the ANSI terminal escapes that turn off all attributes and turn on
bold intensity, respectively.
)
findex(fned)
item(tt(fned) var(name))(
Same as tt(zed -f).  This function does not appear in the zsh
distribution, but can be created by linking tt(zed) to the name tt(fned)
in some directory in your tt(fpath).
)
findex(is-at-least)
item(tt(is-at-least) var(needed) [ var(present) ])(
Perform a greater-than-or-equal-to comparison of two strings having the
format of a zsh version number; that is, a string of numbers and text with
segments separated by dots or dashes.  If the var(present) string is not
provided, tt($ZSH_VERSION) is used.  Segments are paired left-to-right in
the two strings with leading non-number parts ignored.  If one string has
fewer segments than the other, the missing segments are considered zero.

This is useful in startup files to set options and other state that are
not available in all versions of zsh.

example(is-at-least 3.1.6-15 && setopt NO_GLOBAL_RCS
is-at-least 3.1.0 && setopt HIST_REDUCE_BLANKS
is-at-least 2.6-17 || print "You can't use is-at-least here.")
)
findex(nslookup)
item(tt(nslookup) [ var(arg) ... ])(
This wrapper function for the tt(nslookup) command requires the
tt(zsh/zpty) module (see
ifzman(zmanref(zshmodules))\
ifnzman(noderef(The zsh/zpty Module))\
).  It behaves exactly like the standard tt(nslookup)
except that it provides customizable prompts (including a right-side
prompt) and completion of nslookup commands, host names, etc. (if you use
the function-based completion system).  Completion styles may be set with
the context prefix `tt(:completion:nslookup)'.

See also the tt(pager), tt(prompt) and tt(rprompt) styles below.
)
item(tt(run-help))(
See `Accessing On-Line Help'
ifzman(above)\
ifnzman((noderef(Utilities))).
)
item(tt(tetris))(
Zsh was once accused of not being as complete as Emacs,
because it lacked a Tetris game.  This function was written to
refute this vicious slander.

This function must be used as a ZLE widget:

example(autoload -U tetris
zle -N tetris
bindkey var(keys) tetris)

To start a game, execute the widget by typing the var(keys).  Whatever command
line you were editing disappears temporarily, and your keymap is also
temporarily replaced by the Tetris control keys.  The previous editor state
is restored when you quit the game (by pressing `tt(q)') or when you lose.

If you quit in the middle of a game, the next invocation of the tt(tetris)
widget will continue where you left off.  If you lost, it will start a new
game.
)
findex(zargs)
item(tt(zargs) [ var(option) ... tt(-)tt(-) ] [ var(input) ... ] [ tt(-)tt(-) var(command) [ var(arg) ... ] ])(
This function works like GNU xargs, except that instead of reading lines
of arguments from the standard input, it takes them from the command line.
This is useful because zsh, especially with recursive glob operators,
often can construct a command line for a shell function that is longer
than can be accepted by an external command.

The var(option) list represents options of the tt(zargs) command itself,
which are the same as those of tt(xargs).  The var(input) list is the
collection of strings (often file names) that become the arguments of the
tt(command), analogous to the standard input of tt(xargs).  Finally, the
var(arg) list consists of those arguments (usually options) that are
passed to the var(command) each time it runs.  The var(arg) list precedes
the elements from the tt(input) list in each run.  If no var(command) is
provided, then no var(arg) list may be provided, and in that event the
default command is `tt(print)' with arguments `tt(-r -)tt(-)'.

For example, to get a long tt(ls) listing of all plain files in the
current directory or its subdirectories:

example(autoload -U zargs
zargs -- **/*(.) -- ls -l)

Note that `tt(-)tt(-)' is used both to mark the end of the var(option)
list and to mark the end of the var(input) list, so it must appear twice
whenever the var(input) list may be empty.  If there is guaranteed to be
at least one var(input) and the first var(input) does not begin with a
`tt(-)', then the first `tt(-)tt(-)' may be omitted.

In the event that the string `tt(-)tt(-)' is or may be an var(input), the
tt(-e) option may be used to change the end-of-inputs marker.  Note that
this does em(not) change the end-of-options marker.  For example, to use
`tt(..)' as the marker:

example(zargs -e.. -- **/*(.) .. ls -l)

This is a good choice in that example because no plain file can be named
`tt(..)', but the best end-marker depends on the circumstances.

For details of the other tt(zargs) options, see zmanref(xargs) or run
tt(zargs) with the tt(-)tt(-help) option.
)
findex(zcalc)
item(tt(zcalc) [ var(expression) ... ])(
A reasonably powerful calculator based on zsh's arithmetic evaluation
facility.  The syntax is similar to that of formulae in most programming
languages; see
ifzman(the section `Arithmetic Evaluation' in zmanref(zshmisc))\
ifnzman(noderef(Arithmetic Evaluation)) for details.  The mathematical
library tt(zsh/mathfunc) will be loaded if it is available; see
ifzman(the section `The zsh/mathfunc Module' in zmanref(zshmodules))\
ifnzman(noderef(The zsh/mathfunc Module)).  The mathematical functions
correspond to the raw system libraries, so trigonometric functions are
evaluated using radians, and so on.

Each line typed is evaluated as an expression.  The prompt shows a number,
which corresponds to a positional parameter where the result of that
calculation is stored.  For example, the result of the calculation on the
line preceded by `tt(4> )' is available as tt($4).  Full command line
editing, including the history of previous calculations, is available; the
history is saved in the file tt(~/.zcalc_history).  To exit, enter a blank
line or type `tt(q)' on its own.

If arguments are given to tt(zcalc) on start up, they are used to prime the
first few positional parameters.  A visual indication of this is given when
the calculator starts.

The constants tt(PI) (3.14159...) and tt(E) (2.71828...) are provided.
Parameter assignment is possible, but note that all parameters will be put
into the global namespace.

An extra facility is provided for changing the default output base.  Use,
for example, `tt([#16])' to display hexadecimal output preceded by an
indication of the base, or `tt([##16])' just to display the raw number in
the given base.  Bases themselves are always specified in decimal.
`tt([#])' restores the normal output format.  Note that setting an output
base suppresses floating point output; use `tt([#])' to return to normal
operation.

The output base can be initialised by passing the option `tt(-#)var(base)',
for example `tt(zcalc -#16)' (the `tt(#)' may have to be quoted, depending
on the globbing options set).

The prompt is configurable via the parameter tt(ZCALCPROMPT), which
undergoes standard prompt expansion.  The index of the current entry is
stored locally in the first element of the array tt(psvar), which can be
referred to in tt(ZCALCPROMPT) as `tt(%1v)'.  The default prompt is
`tt(%1v> )'.

The output precision may be specified within zcalc by special commands
familiar from many calculators:
startitem()
item(tt(norm))(
The default output format.  It corresponds to the printf tt(%g)
specification.  Typically this shows six decimal digits.
)
item(tt(sci) var(digits))(
Scientific notation, corresponding to the printf tt(%g) output format with
the precision given by var(digits).  This produces either fixed point or
exponential notation depending on the value output.
)
item(tt(fix) var(digits))(
Fixed point notation, corresponding to the printf tt(%f) output format with
the precision given by var(digits).
)
item(tt(eng) var(digits))(
Exponential notation, corresponding to the printf tt(%E) output format with
the precision given by var(digits).
)
enditem()

See the comments in the function for a few extra tips.
)
findex(zed)
xitem(tt(zed) [ tt(-f) ] var(name))
item(tt(zed -b))(
This function uses the ZLE editor to edit a file or function.

Only one var(name) argument is allowed.
If the tt(-f) option is given, the name is taken to be that of
a function; if the function is marked for autoloading, tt(zed) searches
for it in the tt(fpath) and loads it.  Note that functions edited this way
are installed into the current shell, but em(not) written back to the
autoload file.

Without tt(-f), var(name) is the path name of the file to edit, which need
not exist; it is created on write, if necessary.

While editing, the function sets the main keymap to tt(zed) and the
vi command keymap to tt(zed-vicmd).  These will be copied from the existing
tt(main) and tt(vicmd) keymaps if they do not exist the first time tt(zed)
is run.  They can be used to provide special key bindings used only in zed.

If it creates the keymap, tt(zed) rebinds the return key to insert a line
break and `tt(^X^W)' to accept the edit in the tt(zed) keymap, and binds
`tt(ZZ)' to accept the edit in the tt(zed-vicmd) keymap.

The bindings alone can be installed by running `tt(zed -b)'.  This is
suitable for putting into a startup file.  Note that, if rerun,
this will overwrite the existing tt(zed) and tt(zed-vicmd) keymaps.

Completion is available, and styles may be set with the context prefix
`tt(:completion:zed)'.

A zle widget tt(zed-set-file-name) is available.  This can be called by
name from within zed using `tt(\ex zed-set-file-name)' (note, however, that
because of zed's rebindings you will have to type tt(^j) at the end instead
of the return key), or can be bound to a key in either of the tt(zed) or
tt(zed-vicmd) keymaps after `tt(zed -b)' has been run.  When the widget is
called, it prompts for a new name for the file being edited.  When zed
exits the file will be written under that name and the original file will
be left alone.  The widget has no effect with `tt(zed -f)'.

While tt(zed-set-file-name) is running, zed uses the keymap
tt(zed-normal-keymap), which is linked from the main keymap in effect
at the time zed initialised its bindings.  (This is to make the return key
operate normally.)  The result is that if the main keymap has been changed,
the widget won't notice.  This is not a concern for most users.
)
findex(zcp)
findex(zln)
xitem(tt(zcp) [ tt(-finqQvwW) ] var(srcpat) var(dest))
item(tt(zln) [ tt(-finqQsvwW) ] var(srcpat) var(dest))(
Same as tt(zmv -C) and tt(zmv -L), respectively.  These functions do not
appear in the zsh distribution, but can be created by linking tt(zmv) to
the names tt(zcp) and tt(zln) in some directory in your tt(fpath).
)
item(tt(zkbd))(
See `Keyboard Definition'
ifzman(above)\
ifnzman((noderef(Utilities))).
)
findex(zmv)
item(tt(zmv) [ tt(-finqQsvwW) ] [ -C | -L | -M | -p var(program) ] [ -o var(optstring) ] var(srcpat) var(dest) )(
Move (usually, rename) files matching the pattern var(srcpat) to
corresponding files having names of the form given by var(dest), where
var(srcpat) contains parentheses surrounding patterns which will be
replaced in turn by $1, $2, ... in var(dest).  For example,

example(zmv '(*).lis' '$1.txt')

renames `tt(foo.lis)' to `tt(foo.txt)', `tt(my.old.stuff.lis)' to
`tt(my.old.stuff.txt)', and so on.

The pattern is always treated as an tt(EXTENDED_GLOB) pattern.  Any file
whose name is not changed by the substitution is simply ignored.  Any
error (a substitution resulted in an empty string, two substitutions gave
the same result, the destination was an existing regular file and tt(-f)
was not given) causes the entire function to abort without doing anything.

Options:

startsitem()
sitem(tt(-f))(Force overwriting of destination files.  Not currently
passed down to the tt(mv)/tt(cp)/tt(ln) command due to vagaries of
implementations (but you can use tt(-o-f) to do that).)
sitem(tt(-i))(Interactive: show each line to be executed and ask the user
whether to execute it.  `Y' or `y' will execute it, anything else will
skip it.  Note that you just need to type one character.)
sitem(tt(-n))(No execution: print what would happen, but don't do it.)
sitem(tt(-q))(Turn bare glob qualifiers off: now assumed by default, so
this has no effect.)
sitem(tt(-Q))(Force bare glob qualifiers on.  Don't turn this on unless
you are actually using glob qualifiers in a pattern.)
sitem(tt(-s))(Symbolic, passed down to tt(ln); only works with tt(-L).)
sitem(tt(-v))(Verbose: print each command as it's being executed.)
sitem(tt(-w))(Pick out wildcard parts of the pattern, as described above,
and implicitly add parentheses for referring to them.)
sitem(tt(-W))(Just like tt(-w), with the addition of turning wildcards in
the replacement pattern into sequential ${1} .. ${N} references.)
sxitem(tt(-C))
sxitem(tt(-L))
sitem(tt(-M))(Force tt(cp), tt(ln) or tt(mv), respectively, regardless of
the name of the function.)
sitem(tt(-p) var(program))(Call var(program) instead of tt(cp), tt(ln) or
tt(mv).  Whatever it does, it should at least understand the form
ifzman(`var(program) tt(-)tt(-) var(oldname) var(newname)')\
ifnzman(example(var(program) tt(-)tt(-) var(oldname) var(newname)))
where var(oldname) and var(newname) are filenames generated by tt(zmv).)
sitem(tt(-o) var(optstring))(The var(optstring) is split into words and
passed down verbatim to the tt(cp), tt(ln) or tt(mv) command called to
perform the work.  It should probably begin with a `tt(-)'.)
endsitem()

For more complete examples and other implementation details, see the
tt(zmv) source file, usually located in one of the directories named in
your tt(fpath), or in tt(Functions/Misc/zmv) in the zsh distribution.
)
item(tt(zrecompile))(
See `Recompiling Functions'
ifzman(above)\
ifnzman((noderef(Utilities))).
)
findex(zstyle+)
item(tt(zstyle+) var(context) var(style) var(value) [ + var(subcontext) var(style) var(value) ... ])(
This makes defining styles a bit simpler by using a single `tt(+)' as a
special token that allows you to append a context name to the previously
used context name.  Like this:

example(zstyle+ ':foo:bar' style1 value1 \ 
      + ':baz'     style2 value2 \ 
      + ':frob'    style3 value3)

This defines `style1' with `value1' for the context tt(:foo:bar) as usual,
but it also defines `style2' with `value2' for the context
tt(:foo:bar:baz) and `style3' with `value3' for tt(:foo:bar:frob).  Any
var(subcontext) may be the empty string to re-use the first context
unchanged.
)
enditem()

subsect(Styles)

startitem()
kindex(insert-tab, completion style)
item(tt(insert-tab))(
The tt(zed) function em(sets) this style in context `tt(:completion:zed:*)'
to turn off completion when tt(TAB) is typed at the beginning of a line.
You may override this by setting your own value for this context and style.
)
kindex(pager, nslookup style)
item(tt(pager))(
The tt(nslookup) function looks up this style in the context
`tt(:nslookup)' to determine the program used to display output that does
not fit on a single screen.
)
kindex(prompt, nslookup style)
kindex(rprompt, nslookup style)
xitem(tt(prompt))
item(tt(rprompt))(
The tt(nslookup) function looks up this style in the context
`tt(:nslookup)' to set the prompt and the right-side prompt, respectively.
The usual expansions for the tt(PS1) and tt(RPS1) parameters may be used
(see
ifzman(zmanref(zshmisc))\
ifnzman(noderef(Prompt Expansion))\
).
)
enditem()