.. historic nodename: Completion Widgets

Completion Widgets
================================================================================
.. index:: single: completion, widgets; Command

.. index:: single: completion, programmable; Command

.. index:: single: completion, controlling; Command

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

.. only:: man

    :manpage:`zshcompsys(1)`

.. only:: not man

    the next chapter, :ref:`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 :manpage:`zshcompctl`.

Completion widgets are defined by the ``-C`` option to the ``zle``
builtin command provided by the ``zsh/zle`` module (see
:zshsectref:`Zle Builtins <zshzle>`). For example,

.. code-block:: zsh
   :class: example

    zle -C complete expand-or-complete completer

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
(see :zshsectref:`Zle Builtins <zshzle>`),
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``.

.. historic nodename: Completion Special Parameters

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
:zshsectref:`Parameters Used by the Shell <zshparam>`.

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.

.. index:: single: CURRENT; Variable

``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.
    

.. index:: single: IPREFIX; Variable

``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:
    
    
    .. code-block:: zsh
       :class: example

        IPREFIX=${PREFIX%%\=*}=
        PREFIX=${PREFIX#*=}
    
    
    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.
    

.. index:: single: ISUFFIX; Variable

``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.
    

.. index:: single: PREFIX; Variable

``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.
    

.. index:: single: QIPREFIX; Variable

``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`` .
    

.. index:: single: QISUFFIX; Variable

``QISUFFIX``
    
    Like ``QIPREFIX``, but containing the suffix.
    

.. index:: single: SUFFIX; Variable

``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.
    

.. index:: single: compstate; Variable

.. index:: single: completion widgets, examining and setting state in; Command

``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:
    
    
    .. index:: single: all_quotes, compstate; Variable
    
    
    ``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
        ``$'``:var:`...`\ ``'`` and a backslash for strings not starting with a
        quote character.  The first character in the value always corresponds to the
        innermost quoting level.
        
    
    .. index:: single: context, compstate; Variable
    
    
    ``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.
            
        
        
        
    
    .. index:: single: exact, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: exact_string, compstate; Variable
    
    
    ``exact_string``
        
        The string of an exact match if one was found, otherwise unset.
        
    
    .. index:: single: ignored, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: insert, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: insert_positions, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: last_prompt, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: list, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: list_lines, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: list_max, compstate; Variable
    
    
    ``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``.
        
    
    .. index:: single: nmatches, compstate; Variable
    
    
    ``nmatches``
        
        The number of matches added by the completion code so far.
        
    
    .. index:: single: old_insert, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: old_list, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: parameter, compstate; Variable
    
    
    ``parameter``
        
        The name of the parameter when completing in a subscript or in the
        value of a parameter assignment.
        
    
    .. index:: single: pattern_insert, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: pattern_match, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: quote, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: quoting, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: redirect, compstate; Variable
    
    
    ``redirect``
        
        The redirection operator when completing in a redirection position,
        i.e. one of ``<``, ``>``, etc.
        
    
    .. index:: single: restore, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: to_end, compstate; Variable
    
    
    ``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``.
        
    
    .. index:: single: unambiguous, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: unambiguous_cursor, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: unambiguous_positions, compstate; Variable
    
    
    ``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.
        
    
    .. index:: single: vared, compstate; Variable
    
    
    ``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.
        
    
    
    

.. index:: single: words; Variable

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

.. historic nodename: Completion Builtin Commands

Completion Builtin Commands
--------------------------------------------------------------------------------

.. index:: single: compadd; Function

.. index:: single: completion widgets, adding specified matches; Command

``compadd`` [ ``-akqQfenUl12C`` ] [ ``-F`` :var:`array` ]

        ``[-P`` :var:`prefix` ] [ ``-S`` :var:`suffix` ]

        ``[-p`` :var:`hidden-prefix` ] [ ``-s`` :var:`hidden-suffix` ]

        ``[-i`` :var:`ignored-prefix` ] [ ``-I`` :var:`ignored-suffix` ]

        ``[-W`` :var:`file-prefix` ] [ ``-d`` :var:`array` ]

        ``[-J`` :var:`group-name` ] [ ``-X`` :var:`explanation` ] [ ``-x`` :var:`message` ]

        ``[-V`` :var:`group-name` ] [ ``-o`` [ :var:`order` ] ]

        ``[-r`` :var:`remove-chars` ] [ ``-R`` :var:`remove-func` ]

        ``[-D`` :var:`array` ] [ ``-O`` :var:`array` ] [ ``-A`` :var:`array` ]

        ``[-E`` :var:`number` ]

        ``[-M`` :var:`match-spec` ] [ ``--`` ] [ :var:`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:
    
    .. 
    

        :var:`<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 :var:`<apre>` is an optional prefix string
    given with the ``-P`` option.  The :var:`<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.  :var:`<body>` is the part of the match that
    should appear in the list of matches shown to the user.
    The suffixes :var:`<hsuf>`,
    :var:`<asuf>` and :var:`<isuf>` correspond to the prefixes :var:`<hpre>`,
    :var:`<apre>` and :var:`<ipre>` and are given by the options ``-s``, ``-S`` and
    ``-I``, respectively.
    
    The supported flags are:
    
    
    ``-P`` :var:`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`` :var:`suffix`
        
        Like ``-P``, but gives a string to be inserted after each match.
        
    
    ``-p`` :var:`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`` :var:`hidden-suffix`
        
        Like ``-p``, but gives a string to insert after each match.
        
    
    ``-i`` :var:`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`` :var:`ignored-suffix`
        
        Like ``-i``, but gives an ignored suffix.
        
    
    ``-a``
        
        With this flag the :var:`completions` are taken as names of arrays and the
        actual completions are their values.  If only some elements of the
        arrays are needed, the :var:`completions` may also contain subscripts, as in
        ``foo[2,-1]``.
        
    
    ``-k``
        
        With this flag the :var:`completions` are taken as names of associative arrays
        and the actual completions are their keys.  As for ``-a``, the
        :var:`words` may also contain subscripts, as in ``foo[(R)*bar*]``.
        
    
    ``-d`` :var:`array`
        
        This adds per-completion display strings. The :var:`array` should contain one
        element per :var:`completion` given. The completion code will then display the
        first element instead of the first :var:`completion`, and so on. The
        :var:`array` may be given as the name of an array parameter, or directly
        as a literal array enclosed in parentheses. A literal array is a space or
        comma separated list of words; quotes have no special meaning and
        backslashes can be used for escaping (for example, ``(foo\ bar)`` produces
        one element, ``foo bar``, while ``(foo bar)`` produces two elements,
        ``foo`` and ``bar``).
        
        If there are fewer display strings than :var:`completions`, the leftover
        :var:`completions` will be displayed unchanged and if there are more display
        strings than :var:`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`` [ :var:`order` ]
        
        This controls the order in which matches are sorted. :var:`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; additionally, since ordering flags are not
        respected on the default group, a group name must be given explicitly.  See
        ``-J`` and ``-V`` below.
        
        
        ``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 :var:`order` argument is omitted.
            
        
        ``nosort``
            
            This specifies that the :var:`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`` :var:`group-name`
        
        Gives the name of the group that the matches should be stored in.
        
    
    ``-V`` :var:`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`` :var:`explanation`
        
        The :var:`explanation` string will be printed with the list of matches,
        above the group currently selected.
        
        Within the :var:`explanation`, the following sequences may be used to
        specify output attributes as described in
        :zshsectref:`Expansion of Prompt Sequences <zshmisc>`:
        ``%B``, ``%S``, ``%U``, ``%F``, ``%K`` and their lower case
        counterparts, as well as ``%H`` and ``%{...%}``.  ``%F``,
        ``%K``, ``%H`` 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 :zshsectref:`Standard Styles <zshcompsys>`),
        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`` :var:`message`
        
        Like ``-X``, but the :var:`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`` :var:`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
        :var:`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`` :var:`remove-func`
        
        This is another form of the ``-r`` option. When a match
        has been accepted and a suffix has been inserted, the function
        :var:`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
        :zshsectref:`User-Defined Widgets <zshzle>`
        ) to analyse and modify the command line.
        
    
    ``-f``
        
        If this flag is given, all of the matches built from the :var:`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`` :var:`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`` :var:`array`
        
        Specifies an array containing patterns.  :var:`completions` that match one of
        these patterns are ignored, that is, not considered to be matches.
        
        The :var:`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`` :var:`match-spec`
        
        This gives local match specifications as described below in
        :ref:`Completion Matching Control`. This option may be given more than once.
        In this case all :var:`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 :var:`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 :var:`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`` :var:`array`
        
        If this option is given, the :var:`completions` are :emphasis:`not` added to the set of
        matches.  Instead, matching is done as usual and all of the
        :var:`completions` that match
        will be stored in the array parameter whose name is given as :var:`array`.
        
    
    ``-A`` :var:`array`
        
        As the ``-O`` option, except that instead of those of the :var:`completions`
        which
        match being stored in :var:`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 :var:`completions` of ``foo``, this
        option stores the string ``nofoo`` in the array, whereas the ``-O``
        option stores the ``foo`` originally given.
        
    
    ``-D`` :var:`array`
        
        As with ``-O``, the :var:`completions` are not added to the set of matches.
        Instead, whenever the :var:`n`\th :var:`completion` does not
        match, the :var:`n`\th element of the :var:`array` is removed.  Elements
        for which the corresponding :var:`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`` :var:`number`
        
        This option adds :var:`number` empty matches after matching :var:`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 :var:`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.
    

.. index:: single: compset; Function

.. index:: single: completion widgets, modifying special parameters; Command

``compset -p`` :var:`number`

``compset -P`` [ :var:`number` ] :var:`pattern`

``compset -s`` :var:`number`

``compset -S`` [ :var:`number` ] :var:`pattern`

``compset -n`` :var:`begin` [ :var:`end` ]

``compset -N`` :var:`beg-pat` [ :var:`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`` :var:`number`
        
        If the value of the ``PREFIX`` parameter is at least :var:`number`
        characters long, the first :var:`number` characters are removed from it and
        appended to the contents of the ``IPREFIX`` parameter.
        
    
    ``-P`` [ :var:`number` ] :var:`pattern`
        
        If the value of the ``PREFIX`` parameter begins with anything that
        matches the :var:`pattern`, the matched portion is removed from
        ``PREFIX`` and appended to ``IPREFIX``.
        
        Without the optional :var:`number`, the longest match is taken, but
        if :var:`number` is given, anything up to the :var:`number`\th match is
        moved.  If the :var:`number` is negative, the :var:`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`` :var:`number`
        
        As ``-p``, but transfer the last :var:`number` characters from the
        value of ``SUFFIX`` to the front of the value of ``ISUFFIX``.
        
    
    ``-S`` [ :var:`number` ] :var:`pattern`
        
        As ``-P``, but match the last portion of ``SUFFIX`` and transfer the
        matched portion to the front of the value of ``ISUFFIX``.
        
    
    ``-n`` :var:`begin` [ :var:`end` ]
        
        If the current word position as specified by the parameter ``CURRENT``
        is greater than or equal to :var:`begin`, anything up to the
        :var:`begin`\th word is removed from the ``words`` array and the value
        of the parameter ``CURRENT`` is decremented by :var:`begin`.
        
        If the optional :var:`end` is given, the modification is done only if
        the current word position is also less than or equal to :var:`end`. In
        this case, the words from position :var:`end` onwards are also removed from
        the ``words`` array.
        
        Both :var:`begin` and :var:`end` may be negative to count backwards
        from the last element of the ``words`` array.
        
    
    ``-N`` :var:`beg-pat` [ :var:`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 :var:`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 :var:`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 :var:`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:
    
    
    .. code-block:: zsh
       :class: example

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

.. historic nodename: Completion Condition Codes

Completion Condition Codes
--------------------------------------------------------------------------------
.. index:: single: completion widgets, condition codes; Command

The following additional condition codes for use within the ``[[`` :var:`...` ``]]``
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.

.. index:: single: -prefix, within [[; Function

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

.. index:: single: -suffix, within [[; Function

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

.. index:: single: -after, within [[; Function

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

.. index:: single: -between, within [[; Function

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

.. historic nodename: Completion Matching Control

Completion Matching Control
--------------------------------------------------------------------------------

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

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

    
    * appending a ``*`` (matching any number of characters in a completion)
    :emphasis:`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 :emphasis:`match
specification` to the ``compadd`` builtin command through its ``-M`` option
(see :zshsectref:`Completion Builtin Commands <above>`).
A match specification consists of one or more :var:`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 :zshsectref:`Completion Special Parameters <above>`).
    
    * Users of the 
    .. only:: man

        completion system (see :manpage:`zshcompsys(1)`)

     
    .. only:: not man

        :ref:`Completion System`

     should generally not use the ``-M`` option directly, but rather use the
    ``matcher-list`` and ``matcher`` styles (see
    :zshsectref:`Standard Styles <zshcompsys>`).
    

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 consists of either

    
    * the empty string or
    * a sequence of
    
        
        * literal characters (which may be quoted with a ``\``),
        * question marks (``?``),
        * bracket expressions (``[...]``; see :zshsectref:`Glob Operators <zshexpn>`),
        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 (``[:``:var:`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 :var:`n`\th pattern in a brace
    expression, the corresponding part of the match pattern is broadened only with
    the :var:`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 :emphasis:`both` sides of the
    ``=``, the :var:`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 :emphasis:`uppercase` form
behaves exactly like its lowercase counterpart, but adds an additional step
:emphasis:`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 :emphasis:`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:``:var:`word-pat`\ ``=``:var:`match-pat`

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

``B:``:var:`word-pat`\ ``=``:var:`match-pat`

``e:``:var:`word-pat`\ ``=``:var:`match-pat`

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

``L:|``:var:`word-pat`\ ``=``:var:`match-pat`

``r:``:var:`word-pat`\ ``|=``:var:`match-pat`

``R:``:var:`word-pat`\ ``|=``:var:`match-pat`
    
    
    If there is a substring at the ``l:``\eft or ``r:``\ight edge of the current word
    that matches :var:`word-pat`, then broaden the corresponding part of the match
    pattern to additionally match :var:`match-pat`.
    
    For each ``l:``, ``L:``, ``r:`` and ``R:`` matcher (including the ones below),
    the pattern :var:`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:``:var:`anchor`\ ``|``:var:`word-pat`\ ``=``:var:`match-pat`

``L:``:var:`anchor`\ ``|``:var:`word-pat`\ ``=``:var:`match-pat`

``r:``:var:`word-pat`\ ``|``:var:`anchor`\ ``=``:var:`match-pat`

``R:``:var:`word-pat`\ ``|``:var:`anchor`\ ``=``:var:`match-pat`
    
    
    For each substring of the current word that matches :var:`word-pat` and has on
    its ``l:``\eft or ``r:``\ight another substring matching :var:`anchor`, broaden the
    corresponding part of the match pattern to additionally match :var:`match-pat`.
    
    Note that these matchers (and the ones below) modify only what is matched by
    :var:`word-pat`; they do not change the matching behavior of what is matched by
    :var:`anchor` (or :var:`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 :var:`match-pat` may also be ``*`` or ``**``.  ``*``
    can match any part of a completion that does not contain any substrings
    matching :var:`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 also different from ``*``
    and ``**`` in glob expressions.)
    
    
    Examples:
        
        
        ``r:|.=*`` makes the completion ``comp.sources.unix`` a match for the word
        ``..u`` -- but :emphasis:`not` for the word ``.u``.
        
        Given a completion ``--foo``, the matcher ``L:--|no-=`` will complete
        the word ``--no-`` to the match ``--no-foo``.
        
    
    
    

``l:``:var:`anchor`\ ``||``:var:`coanchor`\ ``=``:var:`match-pat`

``L:``:var:`anchor`\ ``||``:var:`coanchor`\ ``=``:var:`match-pat`

``r:``:var:`coanchor`\ ``||``:var:`anchor`\ ``=``:var:`match-pat`

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

        completion system (see :manpage:`zshcompsys(1)`)

    
    .. only:: not man

        :ref:`Completion System`

    , it can allow one match specification to override another.
    

.. historic nodename: Completion Widget Example

Completion Widget Example
--------------------------------------------------------------------------------
.. index:: single: completion widgets, example; Command

The first step is to define the widget:

.. code-block:: zsh
   :class: example

    zle -C complete complete-word complete-files

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

.. code-block:: zsh
   :class: example

    bindkey '^X\t' complete

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.:

.. code-block:: zsh
   :class: example

    complete-files () { compadd - * }

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