zsh-manual-mdbook/zsh_manual/src/Completion-Widgets.md

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**Table of Contents**  *generated with [DocToc](https://github.com/thlorenz/doctoc)*

- [19 Completion Widgets](#19-completion-widgets)
  - [19.1 Description](#191-description)
  - [19.2 Completion Special Parameters](#192-completion-special-parameters)
  - [19.3 Completion Builtin Commands](#193-completion-builtin-commands)
  - [\-](#%5C-)
  - [19.4 Completion Condition Codes](#194-completion-condition-codes)
  - [19.5 Completion Matching Control](#195-completion-matching-control)
  - [19.6 Completion Widget Example](#196-completion-widget-example)

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<span id="Completion-Widgets"></span> <span
id="Completion-Widgets-1"></span>

# 19 Completion Widgets

<span id="index-completion_002c-widgets"></span> <span
id="index-completion_002c-programmable"></span> <span
id="index-completion_002c-controlling"></span>

------------------------------------------------------------------------

<span id="Description"></span>

## 19.1 Description

The shell’s programmable completion mechanism can be manipulated in two
ways; here the low-level features supporting the newer, function-based
mechanism are defined. A complete set of shell functions based on these
features is described in the next chapter, [Completion
System](Completion-System.html#Completion-System), and users with no
interest in adding to that system (or, potentially, writing their own —
see dictionary entry for ‘hubris’) should skip the current section. The
older system based on the compctl builtin command is described in
[Completion Using
compctl](Completion-Using-compctl.html#Completion-Using-compctl).

Completion widgets are defined by the -C option to the zle builtin
command provided by the zsh/zle module (see [The zsh/zle
Module](Zsh-Modules.html#The-zsh_002fzle-Module)). For example,

<div class="example">

```zsh
zle -C complete expand-or-complete completer
```

</div>

defines a widget named ‘complete’. The second argument is the name of
any of the builtin widgets that handle completions: complete-word,
expand-or-complete, expand-or-complete-prefix, menu-complete,
menu-expand-or-complete, reverse-menu-complete, list-choices, or
delete-char-or-list. Note that this will still work even if the widget
in question has been re-bound.

When this newly defined widget is bound to a key using the bindkey
builtin command defined in the zsh/zle module ([Zsh Line
Editor](Zsh-Line-Editor.html#Zsh-Line-Editor)), typing that key will
call the shell function ‘completer’. This function is responsible for
generating completion matches using the builtins described below. As
with other ZLE widgets, the function is called with its standard input
closed.

Once the function returns, the completion code takes over control again
and treats the matches in the same manner as the specified builtin
widget, in this case expand-or-complete.

------------------------------------------------------------------------

<span id="Completion-Special-Parameters"></span> <span
id="Completion-Special-Parameters-1"></span>

## 19.2 Completion Special Parameters

The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE_SPACE_SUFFIX_CHARS are
used by the completion mechanism, but are not special. See [Parameters
Used By The Shell](Parameters.html#Parameters-Used-By-The-Shell).

Inside completion widgets, and any functions called from them, some
parameters have special meaning; outside these functions they are not
special to the shell in any way. These parameters are used to pass
information between the completion code and the completion widget. Some
of the builtin commands and the condition codes use or change the
current values of these parameters. Any existing values will be hidden
during execution of completion widgets; except for compstate, the
parameters are reset on each function exit (including nested function
calls from within the completion widget) to the values they had when the
function was entered.

<span id="index-CURRENT"></span>

CURRENT

This is the number of the current word, i.e. the word the cursor is
currently on in the words array. Note that this value is only correct if
the ksharrays option is not set.

<span id="index-IPREFIX"></span>

IPREFIX

Initially this will be set to the empty string. This parameter functions
like PREFIX; it contains a string which precedes the one in PREFIX and
is not considered part of the list of matches. Typically, a string is
transferred from the beginning of PREFIX to the end of IPREFIX, for
example:

<div class="example">

```zsh
IPREFIX=${PREFIX%%\=*}=
PREFIX=${PREFIX#*=}
```

</div>

causes the part of the prefix up to and including the first equal sign
not to be treated as part of a matched string. This can be done
automatically by the compset builtin, see below.

<span id="index-ISUFFIX"></span>

ISUFFIX

As IPREFIX, but for a suffix that should not be considered part of the
matches; note that the ISUFFIX string follows the SUFFIX string.

<span id="index-PREFIX"></span>

PREFIX

Initially this will be set to the part of the current word from the
beginning of the word up to the position of the cursor; it may be
altered to give a common prefix for all matches.

<span id="index-QIPREFIX"></span>

QIPREFIX

This parameter is read-only and contains the quoted string up to the
word being completed. E.g. when completing ‘"foo’, this parameter
contains the double quote. If the -q option of compset is used (see
below), and the original string was ‘"foo bar’ with the cursor on the
‘bar’, this parameter contains ‘"foo ’.

<span id="index-QISUFFIX"></span>

QISUFFIX

Like QIPREFIX, but containing the suffix.

<span id="index-SUFFIX"></span>

SUFFIX

Initially this will be set to the part of the current word from the
cursor position to the end; it may be altered to give a common suffix
for all matches. It is most useful when the option COMPLETE_IN_WORD is
set, as otherwise the whole word on the command line is treated as a
prefix.

<span id="index-compstate"></span> <span
id="index-completion-widgets_002c-examining-and-setting-state-in"></span>

compstate

This is an associative array with various keys and values that the
completion code uses to exchange information with the completion widget.
The keys are:

<span id="index-all_005fquotes_002c-compstate"></span>

all_quotes

The -q option of the compset builtin command (see below) allows a quoted
string to be broken into separate words; if the cursor is on one of
those words, that word will be completed, possibly invoking ‘compset -q’
recursively. With this key it is possible to test the types of quoted
strings which are currently broken into parts in this fashion. Its value
contains one character for each quoting level. The characters are a
single quote or a double quote for strings quoted with these characters,
a dollars sign for strings quoted with $’`...`’ and a backslash for
strings not starting with a quote character. The first character in the
value always corresponds to the innermost quoting level.

<span id="index-context_002c-compstate"></span>

context

This will be set by the completion code to the overall context in which
completion is attempted. Possible values are:

array_value  
when completing inside the value of an array parameter assignment; in
this case the words array contains the words inside the parentheses.

brace_parameter  
when completing the name of a parameter in a parameter expansion
beginning with ${. This context will also be set when completing
parameter flags following ${(; the full command line argument is
presented and the handler must test the value to be completed to
ascertain that this is the case.

assign_parameter  
when completing the name of a parameter in a parameter assignment.

command  
when completing for a normal command (either in command position or for
an argument of the command).

condition  
when completing inside a ‘\[\[...\]\]’ conditional expression; in this
case the words array contains only the words inside the conditional
expression.

math  
when completing in a mathematical environment such as a ‘((...))’
construct.

parameter  
when completing the name of a parameter in a parameter expansion
beginning with $ but not ${.

redirect  
when completing after a redirection operator.

subscript  
when completing inside a parameter subscript.

value  
when completing the value of a parameter assignment.

<span id="index-exact_002c-compstate"></span>

exact

Controls the behaviour when the REC_EXACT option is set. It will be set
to accept if an exact match would be accepted, and will be unset
otherwise.

If it was set when at least one match equal to the string on the line
was generated, the match is accepted.

<span id="index-exact_005fstring_002c-compstate"></span>

exact_string

The string of an exact match if one was found, otherwise unset.

<span id="index-ignored_002c-compstate"></span>

ignored

The number of completions that were ignored because they matched one of
the patterns given with the -F option to the compadd builtin command.

<span id="index-insert_002c-compstate"></span>

insert

This controls the manner in which a match is inserted into the command
line. On entry to the widget function, if it is unset the command line
is not to be changed; if set to unambiguous, any prefix common to all
matches is to be inserted; if set to automenu-unambiguous, the common
prefix is to be inserted and the next invocation of the completion code
may start menu completion (due to the AUTO_MENU option being set); if
set to menu or automenu menu completion will be started for the matches
currently generated (in the latter case this will happen because the
AUTO_MENU is set). The value may also contain the string ‘tab’ when the
completion code would normally not really do completion, but only insert
the TAB character.

On exit it may be set to any of the values above (where setting it to
the empty string is the same as unsetting it), or to a number, in which
case the match whose number is given will be inserted into the command
line. Negative numbers count backward from the last match (with ‘-1’
selecting the last match) and out-of-range values are wrapped around, so
that a value of zero selects the last match and a value one more than
the maximum selects the first. Unless the value of this key ends in a
space, the match is inserted as in a menu completion, i.e. without
automatically appending a space.

Both menu and automenu may also specify the number of the match to
insert, given after a colon. For example, ‘menu:2’ says to start menu
completion, beginning with the second match.

Note that a value containing the substring ‘tab’ makes the matches
generated be ignored and only the TAB be inserted.

Finally, it may also be set to all, which makes all matches generated be
inserted into the line.

<span id="index-insert_005fpositions_002c-compstate"></span>

insert_positions

When the completion system inserts an unambiguous string into the line,
there may be multiple places where characters are missing or where the
character inserted differs from at least one match. The value of this
key contains a colon separated list of all these positions, as indexes
into the command line.

<span id="index-last_005fprompt_002c-compstate"></span>

last_prompt

If this is set to a non-empty string for every match added, the
completion code will move the cursor back to the previous prompt after
the list of completions has been displayed. Initially this is set or
unset according to the ALWAYS_LAST_PROMPT option.

<span id="index-list_002c-compstate"></span>

list

This controls whether or how the list of matches will be displayed. If
it is unset or empty they will never be listed; if its value begins with
list, they will always be listed; if it begins with autolist or
ambiguous, they will be listed when the AUTO_LIST or LIST_AMBIGUOUS
options respectively would normally cause them to be.

If the substring force appears in the value, this makes the list be
shown even if there is only one match. Normally, the list would be shown
only if there are at least two matches.

The value contains the substring packed if the LIST_PACKED option is
set. If this substring is given for all matches added to a group, this
group will show the LIST_PACKED behavior. The same is done for the
LIST_ROWS_FIRST option with the substring rows.

Finally, if the value contains the string explanations, only the
explanation strings, if any, will be listed and if it contains messages,
only the messages (added with the -x option of compadd) will be listed.
If it contains both explanations and messages both kinds of explanation
strings will be listed. It will be set appropriately on entry to a
completion widget and may be changed there.

<span id="index-list_005flines_002c-compstate"></span>

list_lines

This gives the number of lines that are needed to display the full list
of completions. Note that to calculate the total number of lines to
display you need to add the number of lines needed for the command line
to this value, this is available as the value of the BUFFERLINES special
parameter.

<span id="index-list_005fmax_002c-compstate"></span>

list_max

Initially this is set to the value of the LISTMAX parameter. It may be
set to any other value; when the widget exits this value will be used in
the same way as the value of LISTMAX.

<span id="index-nmatches_002c-compstate"></span>

nmatches

The number of matches added by the completion code so far.

<span id="index-old_005finsert_002c-compstate"></span>

old_insert

On entry to the widget this will be set to the number of the match of an
old list of completions that is currently inserted into the command
line. If no match has been inserted, this is unset.

As with old_list, the value of this key will only be used if it is the
string keep. If it was set to this value by the widget and there was an
old match inserted into the command line, this match will be kept and if
the value of the insert key specifies that another match should be
inserted, this will be inserted after the old one.

<span id="index-old_005flist_002c-compstate"></span>

old_list

This is set to yes if there is still a valid list of completions from a
previous completion at the time the widget is invoked. This will usually
be the case if and only if the previous editing operation was a
completion widget or one of the builtin completion functions. If there
is a valid list and it is also currently shown on the screen, the value
of this key is shown.

After the widget has exited the value of this key is only used if it was
set to keep. In this case the completion code will continue to use this
old list. If the widget generated new matches, they will not be used.

<span id="index-parameter_002c-compstate"></span>

parameter

The name of the parameter when completing in a subscript or in the value
of a parameter assignment.

<span id="index-pattern_005finsert_002c-compstate"></span>

pattern_insert

Normally this is set to menu, which specifies that menu completion will
be used whenever a set of matches was generated using pattern_match (see
below). If it is set to any other non-empty string by the user and menu
completion is not selected by other option settings, the code will
instead insert any common prefix for the generated matches as with
normal completion.

<span id="index-pattern_005fmatch_002c-compstate"></span>

pattern_match

Locally controls the behaviour given by the GLOB_COMPLETE option.
Initially it is set to ‘\*’ if and only if the option is set. The
completion widget may set it to this value, to an empty string (which
has the same effect as unsetting it), or to any other non-empty string.
If it is non-empty, unquoted metacharacters on the command line will be
treated as patterns; if it is ‘\*’, then additionally a wildcard ‘\*’ is
assumed at the cursor position; if it is empty or unset, metacharacters
will be treated literally.

Note that the match specifications given to the compadd builtin command
are not used if this is set to a non-empty string.

<span id="index-quote_002c-compstate"></span>

quote

When completing inside quotes, this contains the quotation character
(i.e. either a single quote, a double quote, or a backtick). Otherwise
it is unset.

<span id="index-quoting_002c-compstate"></span>

quoting

When completing inside single quotes, this is set to the string single;
inside double quotes, the string double; inside backticks, the string
backtick. Otherwise it is unset.

<span id="index-redirect_002c-compstate"></span>

redirect

The redirection operator when completing in a redirection position, i.e.
one of \<, \>, etc.

<span id="index-restore_002c-compstate"></span>

restore

This is set to auto before a function is entered, which forces the
special parameters mentioned above (words, CURRENT, PREFIX, IPREFIX,
SUFFIX, and ISUFFIX) to be restored to their previous values when the
function exits. If a function unsets it or sets it to any other string,
they will not be restored.

<span id="index-to_005fend_002c-compstate"></span>

to_end

Specifies the occasions on which the cursor is moved to the end of a
string when a match is inserted. On entry to a widget function, it may
be single if this will happen when a single unambiguous match was
inserted or match if it will happen any time a match is inserted (for
example, by menu completion; this is likely to be the effect of the
ALWAYS_TO_END option).

On exit, it may be set to single as above. It may also be set to always,
or to the empty string or unset; in those cases the cursor will be moved
to the end of the string always or never respectively. Any other string
is treated as match.

<span id="index-unambiguous_002c-compstate"></span>

unambiguous

This key is read-only and will always be set to the common (unambiguous)
prefix the completion code has generated for all matches added so far.

<span id="index-unambiguous_005fcursor_002c-compstate"></span>

unambiguous_cursor

This gives the position the cursor would be placed at if the common
prefix in the unambiguous key were inserted, relative to the value of
that key. The cursor would be placed before the character whose index is
given by this key.

<span id="index-unambiguous_005fpositions_002c-compstate"></span>

unambiguous_positions

This contains all positions where characters in the unambiguous string
are missing or where the character inserted differs from at least one of
the matches. The positions are given as indexes into the string given by
the value of the unambiguous key.

<span id="index-vared_002c-compstate"></span>

vared

If completion is called while editing a line using the vared builtin,
the value of this key is set to the name of the parameter given as an
argument to vared. This key is only set while a vared command is active.

<span id="index-words"></span>

words

This array contains the words present on the command line currently
being edited.

------------------------------------------------------------------------

<span id="Completion-Builtin-Commands"></span> <span
id="Completion-Builtin-Commands-1"></span>

## 19.3 Completion Builtin Commands

<span id="index-compadd"></span> <span
id="index-completion-widgets_002c-adding-specified-matches"></span>

compadd \[ -akqQfenUl12C \] \[ -F `array` \]

        \[-P `prefix` \] \[ -S `suffix` \]

        \[-p `hidden-prefix` \] \[ -s `hidden-suffix` \]

        \[-i `ignored-prefix` \] \[ -I `ignored-suffix` \]

        \[-W `file-prefix` \] \[ -d `array` \]

        \[-J `group-name` \] \[ -X `explanation` \] \[ -x `message` \]

        \[-V `group-name` \] \[ -o \[ `order` \] \]

        \[-r `remove-chars` \] \[ -R `remove-func` \]

        \[-D `array` \] \[ -O `array` \] \[ -A `array` \]

        \[-E `number` \]

        \[-M `match-spec` \] \[ -- \] \[ `completions` ... \]

This builtin command can be used to add matches directly and control all
the information the completion code stores with each possible
completion. The return status is zero if at least one match was added
and non-zero if no matches were added.

The completion code breaks each match into seven fields in the order:

> `<ipre><apre><hpre><body><hsuf><asuf><isuf>`

The first field is an ignored prefix taken from the command line, the
contents of the IPREFIX parameter plus the string given with the -i
option. With the -U option, only the string from the -i option is used.
The field `<apre>` is an optional prefix string given with the -P
option. The `<hpre>` field is a string that is considered part of the
match but that should not be shown when listing completions, given with
the -p option; for example, functions that do filename generation might
specify a common path prefix this way. `<body>` is the part of the match
that should appear in the list of matches shown to the user. The
suffixes `<hsuf>`, `<asuf>` and `<isuf>` correspond to the prefixes
`<hpre>`, `<apre>` and `<ipre>` and are given by the options -s, -S and
-I, respectively.

The supported flags are:

-P `prefix`  
This gives a string to be inserted before each match. The string given
is not considered as part of the match and any shell metacharacters in
it will not be quoted when the string is inserted.

-S `suffix`  
Like -P, but gives a string to be inserted after each match.

-p `hidden-prefix`  
This gives a string that should be inserted before each match but that
should not appear in the list of matches. Unless the -U option is given,
this string must be matched as part of the string on the command line.

-s `hidden-suffix`  
Like ‘-p’, but gives a string to insert after each match.

-i `ignored-prefix`  
This gives a string to insert just before any string given with the ‘-P’
option. Without ‘-P’ the string is inserted before the string given with
‘-p’ or directly before each match.

-I `ignored-suffix`  
Like -i, but gives an ignored suffix.

-a  
With this flag the `completions` are taken as names of arrays and the
actual completions are their values. If only some elements of the arrays
are needed, the `completions` may also contain subscripts, as in
‘foo\[2,-1\]’.

-k  
With this flag the `completions` are taken as names of associative
arrays and the actual completions are their keys. As for -a, the `words`
may also contain subscripts, as in ‘foo\[(R)\*bar\*\]’.

-d `array`  
This adds per-completion display strings. The `array` should contain one
element per `completion` given. The completion code will then display
the first element instead of the first `completion`, and so on. The
`array` may be given as the name of an array parameter or directly as a
space-separated list of words in parentheses.

If there are fewer display strings than `completions`, the leftover
`completions` will be displayed unchanged and if there are more display
strings than `completions`, the leftover display strings will be
silently ignored.

-l  
This option only has an effect if used together with the -d option. If
it is given, the display strings are listed one per line, not arrayed in
columns.

-o \[ `order` \]  
This controls the order in which matches are sorted. `order` is a
comma-separated list comprising the following possible values. These
values can be abbreviated to their initial two or three characters. Note
that the order forms part of the group name space so matches with
different orderings will not be in the same group.

match  
If given, the order of the output is determined by the match strings;
otherwise it is determined by the display strings (i.e. the strings
given by the -d option). This is the default if ‘-o’ is specified but
the `order` argument is omitted.

nosort  
This specifies that the `completions` are pre-sorted and their order
should be preserved. This value only makes sense alone and cannot be
combined with any others.

numeric  
If the matches include numbers, sort them numerically rather than
lexicographically.

reverse  
Arrange the matches backwards by reversing the sort ordering.

-J `group-name`  
Gives the name of the group that the matches should be stored in.

-V `group-name`  
Like -J but naming an unsorted group. This option is identical to the
combination of -J and -o nosort.

-1  
If given together with the -V option, makes only consecutive duplicates
in the group be removed. If combined with the -J option, this has no
visible effect. Note that groups with and without this flag are in
different name spaces.

-2  
If given together with the -J or -V option, makes all duplicates be
kept. Again, groups with and without this flag are in different name
spaces.

-X `explanation`  
The `explanation` string will be printed with the list of matches, above
the group currently selected.

Within the `explanation`, the following sequences may be used to specify
output attributes (see [Prompt
Expansion](Prompt-Expansion.html#Prompt-Expansion)): ‘%B’, ‘%S’, ‘%U’,
‘%F’, ‘%K’ and their lower case counterparts, as well as ‘%{...%}’.
‘%F’, ‘%K’ and ‘%{...%}’ take arguments in the same form as prompt
expansion. (Note that the sequence ‘%G’ is not available; an argument to
‘%{’ should be used instead.) The sequence ‘%%’ produces a literal ‘%’.

These sequences are most often employed by users when customising the
format style (see [Completion
System](Completion-System.html#Completion-System)), but they must also
be taken into account when writing completion functions, as passing
descriptions with unescaped ‘%’ characters to utility functions such as
\_arguments and \_message may produce unexpected results. If arbitrary
text is to be passed in a description, it can be escaped using e.g.
${my_str//\\%/%%}.

-x `message`  
Like -X, but the `message` will be printed even if there are no matches
in the group.

-q  
The suffix given with -S will be automatically removed if the next
character typed is a blank or does not insert anything, or if the suffix
consists of only one character and the next character typed is the same
character.

-r `remove-chars`  
This is a more versatile form of the -q option. The suffix given with -S
or the slash automatically added after completing directories will be
automatically removed if the next character typed inserts one of the
characters given in the `remove-chars`. This string is parsed as a
characters class and understands the backslash sequences used by the
print command. For example, ‘-r "a-z\\t"’ removes the suffix if the next
character typed inserts a lower case character or a TAB, and ‘-r "^0-9"’
removes the suffix if the next character typed inserts anything but a
digit. One extra backslash sequence is understood in this string: ‘\\-’
stands for all characters that insert nothing. Thus ‘-S "=" -q’ is the
same as ‘-S "=" -r "= \\t\\n\\-"’.

This option may also be used without the -S option; then any
automatically added space will be removed when one of the characters in
the list is typed.

-R `remove-func`  
This is another form of the -r option. When a match has been accepted
and a suffix has been inserted, the function `remove-func` will be
called after the next character typed. It is passed the length of the
suffix as an argument and can use the special parameters available in
ordinary (non-completion) zle widgets (see [Zsh Line
Editor](Zsh-Line-Editor.html#Zsh-Line-Editor)) to analyse and modify the
command line.

-f  
If this flag is given, all of the matches built from the `completions`
are marked as being the names of files. They are not required to be
actual filenames, but if they are, and the option LIST_TYPES is set, the
characters describing the types of the files in the completion lists
will be shown. This also forces a slash to be added when the name of a
directory is completed.

-e  
This flag can be used to tell the completion code that the matches added
are parameter names for a parameter expansion. This will make the
AUTO_PARAM_SLASH and AUTO_PARAM_KEYS options be used for the matches.

-W `file-prefix`  
This string is a pathname that will be prepended to each match together
with any prefix specified by the -p option to form a complete filename
for testing. Hence it is only useful if combined with the -f flag, as
the tests will not otherwise be performed.

-F `array`  
Specifies an array containing patterns. `completions` that match one of
these patterns are ignored, that is, not considered to be matches.

The `array` may be the name of an array parameter or a list of literal
patterns enclosed in parentheses and quoted, as in ‘-F "(\*?.o \*?.h)"’.
If the name of an array is given, the elements of the array are taken as
the patterns.

-Q  
This flag instructs the completion code not to quote any metacharacters
in the matches when inserting them into the command line.

-M `match-spec`  
This gives local match specifications as described below in [Completion
Matching Control](#Completion-Matching-Control). This option may be
given more than once. In this case all `match-spec`s given are
concatenated with spaces between them to form the specification string
to use. Note that they will only be used if the -U option is not given.

-n  
Specifies that matching `completions` are to be added to the set of
matches, but are not to be listed to the user.

-U  
If this flag is given, all `completions` are added to the set of matches
and no matching will be done by the completion code. Normally this is
used in functions that do the matching themselves.

-O `array`  
If this option is given, the `completions` are *not* added to the set of
matches. Instead, matching is done as usual and all of the `completions`
that match will be stored in the array parameter whose name is given as
`array`.

-A `array`  
As the -O option, except that instead of those of the `completions`
which match being stored in `array`, the strings generated internally by
the completion code are stored. For example, with a match specification
of ‘-M "L:\|no="’, a current word of ‘nof’ and `completions` of ‘foo’,
this option stores the string ‘nofoo’ in the array, whereas the -O
option stores the ‘foo’ originally given.

-D `array`  
As with -O, the `completions` are not added to the set of matches.
Instead, whenever the `n`th `completion` does not match, the `n`th
element of the `array` is removed. Elements for which the corresponding
`completion` matches are retained. This option can be used more than
once to remove elements from multiple arrays.

-C  
This option adds a special match which expands to all other matches when
inserted into the line, even those that are added after this option is
used. Together with the -d option it is possible to specify a string
that should be displayed in the list for this special match. If no
string is given, it will be shown as a string containing the strings
that would be inserted for the other matches, truncated to the width of
the screen.

-E `number`  
This option adds `number` empty matches after matching `completions`
have been added. An empty match takes up space in completion listings
but will never be inserted in the line and can’t be selected with menu
completion or menu selection. This makes empty matches only useful to
format completion lists and to make explanatory string be shown in
completion lists (since empty matches can be given display strings with
the -d option). And because all but one empty string would otherwise be
removed, this option implies the -V and -2 options (even if an explicit
-J option is given). This can be important to note as it affects the
name space into which matches are added.

\-  
--  
This flag ends the list of flags and options. All arguments after it
will be taken as the `completions` even if they begin with hyphens.

Except for the -M flag, if any of these flags is given more than once,
the first one (and its argument) will be used.

<span id="index-compset"></span> <span
id="index-completion-widgets_002c-modifying-special-parameters"></span>

compset -p `number`

compset -P \[ `number` \] `pattern`

compset -s `number`

compset -S \[ `number` \] `pattern`

compset -n `begin` \[ `end` \]

compset -N `beg-pat` \[ `end-pat` \]

compset -q

This command simplifies modification of the special parameters, while
its return status allows tests on them to be carried out.

The options are:

-p `number`  
If the value of the PREFIX parameter is at least `number` characters
long, the first `number` characters are removed from it and appended to
the contents of the IPREFIX parameter.

-P \[ `number` \] `pattern`  
If the value of the PREFIX parameter begins with anything that matches
the `pattern`, the matched portion is removed from PREFIX and appended
to IPREFIX.

Without the optional `number`, the longest match is taken, but if
`number` is given, anything up to the `number`th match is moved. If the
`number` is negative, the `number`th longest match is moved. For
example, if PREFIX contains the string ‘a=b=c’, then compset -P ’\*\\=’
will move the string ‘a=b=’ into the IPREFIX parameter, but compset -P 1
’\*\\=’ will move only the string ‘a=’.

-s `number`  
As -p, but transfer the last `number` characters from the value of
SUFFIX to the front of the value of ISUFFIX.

-S \[ `number` \] `pattern`  
As -P, but match the last portion of SUFFIX and transfer the matched
portion to the front of the value of ISUFFIX.

-n `begin` \[ `end` \]  
If the current word position as specified by the parameter CURRENT is
greater than or equal to `begin`, anything up to the `begin`th word is
removed from the words array and the value of the parameter CURRENT is
decremented by `begin`.

If the optional `end` is given, the modification is done only if the
current word position is also less than or equal to `end`. In this case,
the words from position `end` onwards are also removed from the words
array.

Both `begin` and `end` may be negative to count backwards from the last
element of the words array.

-N `beg-pat` \[ `end-pat` \]  
If one of the elements of the words array before the one at the index
given by the value of the parameter CURRENT matches the pattern
`beg-pat`, all elements up to and including the matching one are removed
from the words array and the value of CURRENT is changed to point to the
same word in the changed array.

If the optional pattern `end-pat` is also given, and there is an element
in the words array matching this pattern, the parameters are modified
only if the index of this word is higher than the one given by the
CURRENT parameter (so that the matching word has to be after the
cursor). In this case, the words starting with the one matching end-pat
are also removed from the words array. If words contains no word
matching `end-pat`, the testing and modification is performed as if it
were not given.

-q  
The word currently being completed is split on spaces into separate
words, respecting the usual shell quoting conventions. The resulting
words are stored in the words array, and CURRENT, PREFIX, SUFFIX,
QIPREFIX, and QISUFFIX are modified to reflect the word part that is
completed.

In all the above cases the return status is zero if the test succeeded
and the parameters were modified and non-zero otherwise. This allows one
to use this builtin in tests such as:

<div class="example">

```zsh
if compset -P '*\='; then ...
```

</div>

This forces anything up to and including the last equal sign to be
ignored by the completion code.

compcall \[ -TD \]

This allows the use of completions defined with the compctl builtin from
within completion widgets. The list of matches will be generated as if
one of the non-widget completion functions (complete-word, etc.) had
been called, except that only compctls given for specific commands are
used. To force the code to try completions defined with the -T option of
compctl and/or the default completion (whether defined by compctl -D or
the builtin default) in the appropriate places, the -T and/or -D flags
can be passed to compcall.

The return status can be used to test if a matching compctl definition
was found. It is non-zero if a compctl was found and zero otherwise.

Note that this builtin is defined by the zsh/compctl module.

------------------------------------------------------------------------

<span id="Completion-Condition-Codes"></span> <span
id="Completion-Condition-Codes-1"></span>

## 19.4 Completion Condition Codes

<span id="index-completion-widgets_002c-condition-codes"></span>

The following additional condition codes for use within the \[\[ `...`
\]\] construct are available in completion widgets. These work on the
special parameters. All of these tests can also be performed by the
compset builtin, but in the case of the condition codes the contents of
the special parameters are not modified.

-prefix \[ `number` \] `pattern`  
true if the test for the -P option of compset would succeed.

-suffix \[ `number` \] `pattern`  
true if the test for the -S option of compset would succeed.

-after `beg-pat`  
true if the test of the -N option with only the `beg-pat` given would
succeed.

-between `beg-pat end-pat`  
true if the test for the -N option with both patterns would succeed.

------------------------------------------------------------------------

<span id="Completion-Matching-Control"></span> <span
id="Completion-Matching-Control-1"></span>

## 19.5 Completion Matching Control

When the user invokes completion, the current *word* on the command line
(that is, the word the cursor is currently on) is used to generate a
*match pattern*. Only those *completions* that match the pattern are
offered to the user as *matches*.

The default match pattern is generated from the current word by either

-   appending a ‘\*’ (matching any number of characters in a completion)
    *or,*
-   if the shell option COMPLETE_IN_WORD is set, inserting a ‘\*’ at the
    cursor position.

This narrow pattern can be broadened selectively by passing a *match
specification* to the compadd builtin command through its -M option (see
[Completion Builtin Commands](#Completion-Builtin-Commands)). A match
specification consists of one or more `matchers` separated by
whitespace. Matchers in a match specification are applied one at a time,
from left to right. Once all matchers have been applied, completions are
compared to the final match pattern and non-matching ones are discarded.

-   Note that the -M option is ignored if the current word contains a
    glob pattern and the shell option GLOB_COMPLETE is set or if the
    pattern_match key of the special associative array compstate is set
    to a non-empty value (see [Completion Special
    Parameters](#Completion-Special-Parameters)).
-   Users of the [Completion
    System](Completion-System.html#Completion-System) should generally
    not use the -M option directly, but rather use the matcher-list and
    matcher styles (see the subsection *Standard Styles* in [Completion
    System
    Configuration](Completion-System.html#Completion-System-Configuration)).

Each matcher consists of

-   a case-sensitive letter
-   a ‘:’,
-   one or more patterns separated by pipes (‘\|’),
-   an equals sign (‘=’), and
-   another pattern.

The patterns before the ‘=’ are used to match substrings of the current
word. For each matched substring, the corresponding part of the match
pattern is broadened with the pattern after the ‘=’, by means of a
logical OR.

Each pattern in a matcher cosists of either

-   the empty string or
-   a sequence of
    -   literal characters (which may be quoted with a ‘\\’),
    -   question marks (‘?’),
    -   bracket expressions (‘\[...\]’; see the subsection *Glob
        Operators* in [Filename
        Generation](Expansion.html#Filename-Generation)), and/or
    -   brace expressions (see below).

Other shell patterns are not allowed.

A brace expression, like a bracket expression, consists of a list of

-   literal characters,
-   ranges (‘0-9’), and/or
-   character classes (‘\[:`name`:\]’).

However, they differ from each other as follows:

-   A brace expression is delimited by a pair of braces (‘{...}’).
-   Brace expressions do not support negations. That is, an initial ‘!’
    or ‘^’ has no special meaning and will be interpreted as a literal
    character.
-   When a character in the current word matches the `n`th pattern in a
    brace expression, the corresponding part of the match pattern is
    broadened only with the `n`th pattern of the brace expression on the
    other side of the ‘=’, if there is one; if there is no brace
    expression on the other side, then this pattern is the empty string.
    However, if either brace expression has more elements than the
    other, then the excess entries are simply ignored. When comparing
    indexes, each literal character or character class counts as one
    element, but each range is instead expanded to the full list of
    literal characters it represents. Additionally, if on *both* sides
    of the ‘=’, the `n`th pattern is ‘\[:upper:\]’ or ‘\[:lower:\]’,
    then these are expanded as ranges, too.

Note that, although the matching system does not yet handle multibyte
characters, this is likely to be a future extension. Hence, using
‘\[:upper:\]’ and ‘\[:lower:\]’ is recommended over ‘A-Z’ and ‘a-z’.

Below are the different forms of matchers supported. Each *uppercase*
form behaves exactly like its lowercase counterpart, but adds an
additional step *after* the match pattern has filtered out non-matching
completions: Each of a match’s substrings that was matched by a
subpattern from an uppercase matcher is replaced with the corresponding
substring of the current word. However, patterns from *lowercase*
matchers have higher weight: If a substring of the current word was
matched by patterns from both a lowercase and an uppercase matcher, then
the lowercase matcher’s pattern wins and the corresponding part of the
match is not modified.

Unless indicated otherwise, each example listed assumes COMPLETE_IN_WORD
to be unset (as it is by default).

m:`word-pat`=`match-pat`  
M:`word-pat`=`match-pat`  
For each substring of the current word that matches `word-pat`, broaden
the corresponding part of the match pattern to additionally match
`match-pat`.

Examples:  
m:{\[:lower:\]}={\[:upper:\]} lets any lower case character in the
current word be completed to itself or its uppercase counterpart. So,
the completions ‘foo’, ‘FOO’ and ‘Foo’ will are be considered matches
for the word ‘fo’.

M:\_= inserts every underscore from the current word into each match, in
the same relative position, determined by matching the substrings around
it. So, given a completion ‘foo’, the word ‘f_o’ will be completed to
the match ‘f_oo’, even though the latter was not present as a
completion.

b:`word-pat`=`match-pat`  
B:`word-pat`=`match-pat`  
e:`word-pat`=`match-pat`  
E:`word-pat`=`match-pat`  
For each consecutive substring at the b:eginning or e:nd of the current
word that matches `word-pat`, broaden the corresponding part of the
match pattern to additionally match `match-pat`.

Examples:  
‘b:-=+’ lets any number of minuses at the start of the current word be
completed to a minus or a plus.

‘B:0=’ adds all zeroes at the beginning of the current word to the
beginning of each match.

l:\|`word-pat`=`match-pat`  
L:\|`word-pat`=`match-pat`  
R:`word-pat`\|=`match-pat`  
r:`word-pat`\|=`match-pat`  
If there is a substring at the l:eft or r:ight edge of the current word
that matches `word-pat`, then broaden the corresponding part of the
match pattern to additionally match `match-pat`.

For each l:, L:, r: and R: matcher (including the ones below), the
pattern `match-pat` may also be a ‘\*’. This matches any number of
characters in a completion.

Examples:  
‘r:\|=\*’ appends a ‘\*’ to the match pattern, even when
COMPLETE_IN_WORD is set and the cursor is not at the end of the current
word.

If the current word starts with a minus, then ‘L:\|-=’ will prepend it
to each match.

l:`anchor`\|`word-pat`=`match-pat`  
L:`anchor`\|`word-pat`=`match-pat`  
r:`word-pat`\|`anchor`=`match-pat`  
R:`word-pat`\|`anchor`=`match-pat`  
For each substring of the current word that matches `word-pat` and has
on its l:eft or r:ight another substring matching `anchor`, broaden the
corresponding part of the match pattern to additionally match
`match-pat`.

Note that these matchers (and the ones below) modify only what is
matched by `word-pat`; they do not change the matching behavior of what
is matched by `anchor` (or `coanchor`; see the matchers below). Thus,
unless its corresponding part of the match pattern has been modified,
the anchor in the current word has to match literally in each
completion, just like any other substring of the current word.

If a matcher includes at least one anchor (which includes the matchers
with two anchors, below), then `match-pat` may also be ‘\*’ or ‘\*\*’.
‘\*’ can match any part of a completion that does not contain any
substrings matching `anchor`, whereas a ‘\*\*’ can match any part of a
completion, period. (Note that this is different from the behavior of
‘\*’ in the anchorless forms of ‘l:’ and ‘r:’ and and also different
from ‘\*’ and ‘\*\*’ in glob expressions.)

Examples:  
‘r:\|.=\*’ makes the completion ‘comp.sources.unix’ a match for the word
‘..u’ — but *not* for the word ‘.u’.

Given a completion ‘--foo’, the matcher ‘L:–\|no-=’ will complete the
word ‘--no-’ to the match ‘--no-foo’.

l:`anchor`\|\|`coanchor`=`match-pat`  
L:`anchor`\|\|`coanchor`=`match-pat`  
r:`coanchor`\|\|`anchor`=`match-pat`  
R:`coanchor`\|\|`anchor`=`match-pat`  
For any two consecutive substrings of the current word that match
`anchor` and `coanchor`, in the order given, insert the pattern
`match-pat` between their corresponding parts in the match pattern.

Note that, unlike `anchor`, the pattern `coanchor` does not change what
‘\*’ can match.

Examples:  
‘r:?\|\|\[\[:upper:\]\]=\*’ will complete the current word ‘fB’ to
‘fooBar’, but it will not complete it to ‘fooHooBar’ (because ‘\*’ here
cannot match anything that includes a match for ‘\[\[:upper:\]\]), nor
will it complete ‘B’ to ‘fooBar’ (because there is no character in the
current word to match `coanchor`).

Given the current word ‘pass.n’ and a completion ‘pass.byname’, the
matcher ‘L:.\|\|\[\[:alpha:\]\]=by’ will produce the match ‘pass.name’.

x:  
Ignore this matcher and all matchers to its right.

This matcher is used to mark the end of a match specification. In a
single standalone list of matchers, this has no use, but where match
specifications are concatenated, as is often the case when using the
[Completion System](Completion-System.html#Completion-System), it can
allow one match specification to override another.

------------------------------------------------------------------------

<span id="Completion-Widget-Example"></span> <span
id="Completion-Widget-Example-1"></span>

## 19.6 Completion Widget Example

<span id="index-completion-widgets_002c-example"></span>

The first step is to define the widget:

<div class="example">

```zsh
zle -C complete complete-word complete-files
```

</div>

Then the widget can be bound to a key using the bindkey builtin command:

<div class="example">

```zsh
bindkey '^X\t' complete
```

</div>

After that the shell function complete-files will be invoked after
typing control-X and TAB. The function should then generate the matches,
e.g.:

<div class="example">

```zsh
complete-files () { compadd - * }
```

</div>

This function will complete files in the current directory matching the
current word.

------------------------------------------------------------------------

This document was generated on *May 14, 2022* using [*texi2html
5.0*](http://www.nongnu.org/texi2html/).  
Zsh version 5.9, released on May 14, 2022.