Descriptions follow for utility functions that may be
useful when writing completion functions. If functions are installed in
subdirectories, most of these reside in the
Base
subdirectory. Like the example
functions for commands in the distribution, the utility functions
generating matches all follow the convention of returning status zero if they
generated completions and non-zero if no matching completions could be
added.
_absolute_command_paths
This function completes external commands as absolute paths (unlike
_command_names -e
which completes their basenames). It takes no
arguments.
_all_labels
[ -x
] [ -12VJ
] tag name descr [ command arg ... ]This is a convenient interface to the _next_label
function below,
implementing the loop shown in the _next_label
example. The
command and its arguments are called to generate the matches. The
options stored in the parameter name will automatically be inserted
into the args passed to the command. Normally, they are put
directly after the command, but if one of the args is a single
hyphen, they are inserted directly before that. If the hyphen is the last
argument, it will be removed from the argument list before the
command is called. This allows _all_labels
to be used in almost all
cases where the matches can be generated by a single call to the
compadd
builtin command or by a call to one of the utility functions.
For example:
local expl ... if _requested foo; then ... _all_labels foo expl '...' compadd ... - $matches fi
Will complete the strings from the matches
parameter, using
compadd
with additional options which will take precedence over
those generated by _all_labels
.
_alternative
[ -O
name ] [ -C
name ] spec ...This function is useful in simple cases where multiple tags are available.
Essentially it implements a loop like the one described for the _tags
function below.
The tags to use and the action to perform if a tag is requested are
described using the specs which are of the form:
‘tag:
descr:
action’. The tags are offered using
_tags
and if the tag is requested, the action is executed with the
given description descr. The actions are those accepted
by the _arguments
function (described below), with the following
exceptions:
->
state’ and ‘=
...’ forms are not supported.
((a\:bar b\:baz
))
’ form does not need
the colon to be escaped, since the specs have no colon-separated fields
after the action.
For example, the action may be a simple function call:
_alternative \ 'users:user:_users' \ 'hosts:host:_hosts'
offers usernames and hostnames as possible matches,
generated by the _users
and _hosts
functions respectively.
Like _arguments
, this function uses _all_labels
to execute
the actions, which will loop over all sets of tags. Special handling is
only required if there is an additional valid tag, for example inside a
function called from _alternative
.
The option ‘-O
name’ is used in the same way as by the
_arguments
function. In other words, the elements of the name
array will be passed to compadd
when executing an action.
Like _tags
this function supports the -C
option to give a
different name for the argument context field.
_arguments
[ -nswWCRS
] [ -A
pat ] [ -O
name ] [ -M
matchspec ]
[ :
] spec ..._arguments
[ opt ... ] -
-
[ -l
] [ -i
pats ] [ -s
pair ]
[ helpspec ...]This function can be used to give a complete specification for completion for a command whose arguments follow standard UNIX option and argument conventions.
Options Overview
Options to _arguments
itself must be in separate words, i.e. -s -w
,
not -sw
. The options are followed by specs that describe options and
arguments of the analyzed command. To avoid ambiguity, all
options to _arguments
itself may be separated from the spec forms
by a single colon.
The ‘-
-
’
form is used to intuit spec forms from the help output of the command
being analyzed, and is described in detail below. The opts for the
‘-
-
’ form are otherwise the same options as the first form. Note
that ‘-s
’ following ‘-
-
’ has a distinct meaning from ‘-s
’
preceding ‘-
-
’, and both may appear.
The option switches -s
, -S
, -A
, -w
, and -W
affect how
_arguments
parses the analyzed command line’s options. These switches are
useful for commands with standard argument parsing.
The options of _arguments
have the following meanings:
-n
With this option, _arguments
sets the parameter NORMARG
to the position of the first normal argument in the $words
array,
i.e. the position after the end of the options. If that argument
has not been reached, NORMARG
is set to -1
. The caller
should declare ‘integer NORMARG
’ if the -n
option is passed;
otherwise the parameter is not used.
-s
Enable option stacking for single-letter options, whereby multiple
single-letter options may be combined into a single word. For example,
the two options ‘-x
’ and ‘-y
’ may be combined into
a single word ‘-xy
’. By default, every word corresponds to a single
option name (‘-xy
’ is a single option named ‘xy
’).
Options beginning with a single hyphen or plus sign are eligible for stacking; words beginning with two hyphens are not.
Note that -s
after -
-
has a different meaning, which is documented
in the segment entitled ‘Deriving spec forms from the help output’.
-w
In combination with -s
, allow option stacking
even if one or more of the options take
arguments. For example, if -x
takes an argument, with no
-s
, ‘-xy
’ is considered as a single (unhandled) option; with
-s
, -xy
is an option with the argument ‘y
’; with both -s
and -w
, -xy
is the option -x
and the option -y
with
arguments to -x
(and to -y
, if it takes arguments) still to come
in subsequent words.
-W
This option takes -w
a stage further: it is possible to
complete single-letter options even after an argument that occurs in the
same word. However, it depends on the action performed whether options
will really be completed at this point. For more control, use a
utility function like _guard
as part of the action.
-C
Modify the curcontext
parameter for an action of the form ‘->
state’.
This is discussed in detail below.
-R
Return status 300 instead of zero when a $state
is to
be handled, in the ‘->
string’ syntax.
-S
Do not complete options after a ‘-
-
’ appearing on the line,
and ignore the ‘-
-
’. For example, with -S
, in the line
foobar -x -- -y
the ‘-x
’ is considered an option, the ‘-y
’ is considered an
argument, and the ‘-
-
’ is considered to be neither.
-A
patDo not complete options after the first non-option
argument on the line. pat is a pattern matching
all strings which are not to be taken as arguments. For example, to make
_arguments
stop completing options after the first normal argument, but
ignoring all strings starting with a hyphen even if they are not described
by one of the optspecs, the form is ‘-A "-*"
’.
-O
namePass the elements of the array name as arguments to functions called to execute actions. This is discussed in detail below.
-M
matchspecUse the match specification matchspec for completing option names and values.
The default matchspec allows partial word completion after ‘_
’ and
‘-
’, such as completing ‘-f-b
’ to ‘-foo-bar
’. The default
matchspec is:
r:|[_-]=* r:|=*
-0
When populating values of the ‘opt_args
’ associative array, don’t
backslash-escape colons and backslashes and use NUL rather than colon for
joining multiple values. This option is described in more detail below, under
the heading specs: actions.
specs: overview
Each of the following forms is a spec describing individual sets of options or arguments on the command line being analyzed.
:
message:
action::
message:
actionThis describes the n’th normal argument. The message will be printed above the matches generated and the action indicates what can be completed in this position (see below). If there are two colons before the message the argument is optional. If the message contains only white space, nothing will be printed above the matches unless the action adds an explanation string itself.
:
message:
action::
message:
actionSimilar, but describes the next argument, whatever number that happens to be. If all arguments are specified in this form in the correct order the numbers are unnecessary.
*:
message:
action*::
message:
action*:::
message:
actionThis describes how arguments (usually non-option arguments, those not
beginning with -
or +
) are to be completed when neither
of the first two forms was provided. Any number of arguments can
be completed in this fashion.
With two colons before the message, the words
special array and
the CURRENT
special parameter are modified to refer only to the
normal arguments when the action is executed or evaluated. With
three colons before the message they are modified to refer only to
the normal arguments covered by this description.
:
...This describes an option. The colon indicates handling for one or more arguments to the option; if it is not present, the option is assumed to take no arguments.
The following forms are available for the initial optspec, whether or not the option has arguments.
*
optspecHere optspec is one of the remaining forms below. This indicates the following optspec may be repeated. Otherwise if the corresponding option is already present on the command line to the left of the cursor it will not be offered again.
-
optname+
optnameIn the simplest form the optspec is just the option name beginning
with a minus or a plus sign, such as ‘-foo
’. The first argument for
the option (if any) must follow as a separate word directly after the
option.
Either of ‘-+
optname’ and ‘+-
optname’ can be used to
specify that -
optname and +
optname are both valid.
In all the remaining forms, the leading ‘-
’ may be replaced by or
paired with ‘+
’ in this way.
-
optname-
The first argument of the option must come directly after the option name
in the same word. For example, ‘-foo-:
...’ specifies that
the completed option and argument will look like ‘-foo
arg’.
-
optname+
The first argument may appear immediately after optname in the same
word, or may appear as a separate word after the option. For example,
‘-foo+:
...’ specifies that the completed option and argument
will look like either ‘-foo
arg’ or ‘-foo
arg’.
-
optname=
The argument may appear as the next word, or in same word as the option
name provided that it is separated from it by an equals sign, for
example ‘-foo=
arg’ or ‘-foo
arg’.
-
optname=-
The argument to the option must appear after an equals sign in the same word, and may not be given in the next argument.
[
explanation]
An explanation string may be appended to any of the preceding forms of
optspec by enclosing it in brackets, as in ‘-q[query operation]
’.
The verbose
style is used to decide whether the explanation strings
are displayed with the option in a completion listing.
If no bracketed explanation string is given but the auto-description
style is set and only one argument is described for this optspec, the
value of the style is displayed, with any appearance of the sequence
‘%d
’ in it replaced by the message of the first optarg
that follows the optspec; see below.
It is possible for options with a literal ‘+
’ or ‘=
’ to
appear, but that character must be quoted, for example ‘-\+
’.
Each optarg following an optspec must take one of the following forms:
:
message:
action::
message:
actionAn argument to the option; message and action are treated as for ordinary arguments. In the first form, the argument is mandatory, and in the second form it is optional.
This group may be repeated for options which take multiple arguments.
In other words,
:
message1:
action1:
message2:
action2
specifies that the option takes two arguments.
:*
pattern:
message:
action:*
pattern::
message:
action:*
pattern:::
message:
actionThis describes multiple arguments. Only the last optarg for
an option taking multiple arguments may be
given in this form. If the pattern is empty (i.e. :*:
), all
the remaining words on the line are to be completed as described by the
action; otherwise, all the words up to and including a word matching
the pattern are to be completed using the action.
Multiple colons are treated as for the ‘*:
...’ forms for
ordinary arguments: when the message is preceded by two colons,
the words
special array and the CURRENT
special parameter are
modified during the execution or evaluation of the action to refer
only to the words after the option. When preceded by three colons, they
are modified to refer only to the words covered by this description.
Any literal colon in an optname, message, or action
must be preceded by a backslash, ‘\:
’.
Each of the forms above may be preceded by a list in parentheses
of option names and argument numbers. If the given option is on
the command line, the options and arguments indicated in parentheses
will not be offered. For example,
‘(-two -three 1)-one:
...’ completes the option ‘-one
’; if this
appears on the command line, the options -two
and -three
and the
first ordinary argument will not be completed after it.
‘(-foo):
...’ specifies an ordinary argument completion;
-foo
will not be completed if that argument is already present.
Other items may appear in the list of excluded options to indicate
various other items that should not be applied when the current
specification is matched: a single star (*
) for the rest arguments
(i.e. a specification of the form ‘*:
...’); a colon (:
)
for all normal (non-option-) arguments; and a hyphen (-
) for all
options. For example, if ‘(*)
’ appears before an option and the
option appears on the command line, the list of remaining arguments
(those shown in the above table beginning with ‘*:
’) will not be
completed.
To aid in reuse of specifications, it is possible to precede any of the
forms above with ‘!
’; then the form will no longer be completed,
although if the option or argument appears on the command line they will
be skipped as normal. The main use for this is when the arguments are
given by an array, and _arguments
is called repeatedly for more
specific contexts: on the first call ‘_arguments $global_options
’ is
used, and on subsequent calls ‘_arguments !$^global_options
’.
specs: actions
In each of the forms above the action determines how
completions should be generated. Except for the ‘->
string’
form below, the action will be executed by calling the
_all_labels
function to process all tag labels. No special handling
of tags is needed unless a function call introduces a new one.
The functions called to execute actions will be called with the
elements of the array named by the ‘-O
name’ option as arguments.
This can be used, for example, to pass the same set of options for the
compadd
builtin to all actions.
The forms for action are as follows.
(single unquoted space)This is useful where an argument is required but it is not possible or desirable to generate matches for it. The message will be displayed but no completions listed. Note that even in this case the colon at the end of the message is needed; it may only be omitted when neither a message nor an action is given.
(
item1 item2 ...)
One of a list of possible matches, for example:
:foo:(foo bar baz
)
((item1\:desc1 ...))
Similar to the above, but with descriptions for each possible match. Note the backslash before the colon. For example,
:foo:((a\:bar b\:baz
))
The matches will be listed together with their descriptions if the
description
style is set with the values
tag in the context.
->
string ¶In this form, _arguments
processes the arguments and options and then
returns control to the calling function with parameters set to indicate the
state of processing; the calling function then makes its own arrangements
for generating completions. For example, functions that implement a state
machine can use this type of action.
Where _arguments
encounters action in the ‘->
string’
format, it will strip all leading and trailing whitespace from string
and set the array state
to the set of all strings for which an
action is to be performed. The elements of the array state_descr
are
assigned the corresponding message field from each optarg
containing such an action.
By default and in common with all other well behaved completion
functions, _arguments returns status zero if it was able to add matches and
non-zero otherwise. However, if the -R
option is given,
_arguments
will instead return a status of 300 to indicate that
$state
is to be handled.
In addition to $state
and $state_descr
, _arguments
also
sets the global
parameters ‘context
’, ‘line
’ and ‘opt_args
’ as described
below, and does not reset any changes made to the special parameters
such as PREFIX
and words
. This gives the calling function the
choice of resetting these parameters or propagating changes in them.
A function calling _arguments
with at least
one action containing a ‘->
string’ must therefore declare
appropriate local parameters:
local context state state_descr line typeset -A opt_args
to prevent _arguments
from altering the global environment.
{
eval-string}
¶A string in braces is evaluated as shell code to generate matches. If the eval-string itself does not begin with an opening parenthesis or brace it is split into separate words before execution.
=
actionIf the action starts with ‘=
’ (an equals sign followed by a
space), _arguments
will insert the contents of the argument
field of the current context as the new first element in the words
special array and increment the value of the CURRENT
special
parameter. This has the effect of inserting a dummy word onto the
completion command line while not changing the point at which completion is
taking place.
This is most useful with one of the specifiers that restrict the words on
the command line on which the action is to operate (the two- and
three-colon forms above). One particular use is when an action itself
causes _arguments
on a restricted range; it is necessary to use this
trick to insert an appropriate command name into the range for the second
call to _arguments
to be able to parse the line.
word...This covers all forms other than those above. If the action starts with a space, the remaining list of words will be invoked unchanged.
Otherwise it will be invoked with some extra strings placed after the
first word; these are to be passed down as options to the compadd
builtin. They ensure that the state specified by _arguments
, in
particular the descriptions of options and arguments, is correctly passed
to the completion command. These additional arguments
are taken from the array parameter ‘expl
’; this will be set up
before executing the action and hence may be referred to inside it,
typically in an expansion of the form ‘$expl[@]
’ which preserves empty
elements of the array.
During the performance of the action the array ‘line
’ will be set to
the normal arguments from the command line, i.e. the words from the
command line after the command name excluding all options and their
arguments. Options are stored in the associative array
‘opt_args
’ with option names as keys and their arguments as
the values. By default, all colons and backslashes in the value are escaped
with backslashes, and if an option has multiple arguments (for example, when
using an optspec of the form ‘*
optspec’), they are joined with
(unescaped) colons. However, if the -0
option was passed, no backslash
escaping is performed, and multiple values are joined with NUL bytes. For
example, after ‘zsh -o foo:foo -o bar:bar -o <TAB>
’, the contents of
‘opt_args
’ would be
typeset -A opt_args=( [-o]='foo\:foo:bar\:bar:' )
by default, and
typeset -A opt_args=( [-o]=$'foo:foo\x00bar:bar\x00' )
if _arguments
had been called with the -0
option.
The parameter ‘context
’ is set when returning to the calling function
to perform an action of the form ‘->
string’. It is set to an
array of elements corresponding to the elements of $state
. Each
element is a suitable name for the argument field of the context: either a
string of the form ‘option
-opt-
n’ for the n’th
argument of the option -opt, or a string of the form
‘argument-
n’ for the n’th argument. For ‘rest’ arguments,
that is those in the list at the end not handled by position, n is the
string ‘rest
’. For example, when completing the argument of the -o
option, the name is ‘option-o-1
’, while for the second normal
(non-option-) argument it is ‘argument-2
’.
Furthermore, during the evaluation of the action the context name in
the curcontext
parameter is altered to append the same string that is
stored in the context
parameter.
The option -C
tells _arguments
to modify the curcontext
parameter for an action of the form ‘->
state’. This is the
standard parameter used to keep track of the current context. Here it
(and not the context
array) should be made local to the calling
function to avoid passing back the modified value and should be
initialised to the current value at the start of the function:
local curcontext="$curcontext"
This is useful where it is not possible for multiple states to be valid together.
Grouping Options
Options can be grouped to simplify exclusion lists. A group is
introduced with ‘+
’ followed by a name for the group in the
subsequent word. Whole groups can then be referenced in an exclusion
list or a group name can be used to disambiguate between two forms of
the same option. For example:
_arguments \ '(group2--x)-a' \ + group1 \ -m \ '(group2)-n' \ + group2 \ -x -y
If the name of a group is specified in the form
‘(
name)
’ then only one value from that group
will ever be completed; more formally, all specifications are mutually
exclusive to all other specifications in that group. This is useful for
defining options that are aliases for each other. For example:
_arguments \ -a -b \ + '(operation)' \ {-c,--compress}'[compress]' \ {-d,--decompress}'[decompress]' \ {-l,--list}'[list]'
If an option in a group appears on the command line, it is stored in the
associative array ‘opt_args
’ with ’group-
option’
as a key. In the example above, a key ‘operation--c
’ is used if the option
‘-c
’ is present on the command line.
Specifying Multiple Sets of Arguments
It is possible to specify multiple sets of options and arguments with the sets separated by single hyphens. This differs from groups in that sets are considered to be mutually exclusive of each other.
Specifications before the first set and from any group are common to all sets. For example:
_arguments \ -a \ - set1 \ -c \ - set2 \ -d \ ':arg:(x2 y2)'
This defines two sets. When the command line contains the option
‘-c
’, the ‘-d
’ option and the argument will not be considered
possible completions. When it contains ‘-d
’ or an argument, the
option ‘-c
’ will not be considered. However, after ‘-a
’
both sets will still be considered valid.
As for groups, the name of a set may appear in exclusion lists, either alone or preceding a normal option or argument specification.
The completion code has to parse the command line separately for each
set. This can be slow so sets should only be used when necessary.
A useful alternative is often an option specification with rest-arguments
(as in ‘-foo:*:...
’); here the option -foo
swallows up all
remaining arguments as described by the optarg definitions.
Deriving spec forms from the help output
The option ‘-
-
’ allows _arguments
to work out the names of long
options that support the ‘-
-help
’ option which is standard in many
GNU commands. The command word is called with the argument
‘-
-help
’ and the output examined for option names. Clearly, it can
be dangerous to pass this to commands which may not support this option as
the behaviour of the command is unspecified.
In addition to options, ‘_arguments -
-
’ will try to deduce the
types of arguments available for options when the form
‘-
-
opt=
val’ is valid. It is also possible to provide
hints by examining the help text of the command and adding helpspec of
the form ‘pattern:
message:
action’; note that other
_arguments
spec forms are not used. The pattern is matched
against the help text for an option, and if it matches the message and
action are used as for other argument specifiers. The special case
of ‘*:
’ means both message and action are empty, which has
the effect of causing options having no description in the help output to
be ordered in listings ahead of options that have a description.
For example:
_arguments -- '*\*:toggle:(yes no)' \ '*=FILE*:file:_files' \ '*=DIR*:directory:_files -/' \ '*=PATH*:directory:_files -/'
Here, ‘yes
’ and ‘no
’ will be completed as the argument of
options whose description ends in a star; file names will be completed for
options that contain the substring ‘=FILE
’ in the description; and
directories will be completed for options whose description contains
‘=DIR
’ or ‘=PATH
’. The last three are in fact the default and so
need not be given explicitly, although it is possible to override the use
of these patterns. A typical help text which uses this feature is:
-C, --directory=DIR change to directory DIR
so that the above specifications will cause directories to be completed
after ‘-
-directory
’, though not after ‘-C
’.
Note also that _arguments
tries to find out automatically if the
argument for an option is optional. This can be specified explicitly by
doubling the colon before the message.
If the pattern ends in ‘(-)
’, this will be removed from the
pattern and the action will be used only directly after the
‘=
’, not in the next word. This is the behaviour of a normal
specification defined with the form ‘=-
’.
By default, the command (with the option ‘--help
’) is run after
resetting all the locale categories (except for LC_CTYPE
) to ‘C
’.
If the localized help output is known to work, the option ‘-l
’ can
be specified after the ‘_arguments -
-
’ so that the command is
run in the current locale.
The ‘_arguments -
-
’ can be followed by the option ‘-i
patterns’ to give patterns for options which are not to be
completed. The patterns can be given as the name of an array parameter
or as a literal list in parentheses. For example,
_arguments -- -i \ "(--(en|dis)able-FEATURE*)"
will cause completion to ignore the options
‘-
-enable-FEATURE
’ and ‘-
-disable-FEATURE
’ (this example is
useful with GNU configure
).
The ‘_arguments -
-
’ form can also be followed by the option ‘-s
pair’ to describe option aliases. The pair consists of a list
of alternating patterns and corresponding replacements, enclosed in parens
and quoted so that it forms a single argument word in the _arguments
call.
For example, some configure
-script help output describes options only
as ‘-
-enable-foo
’, but the script also accepts the negated form
‘-
-disable-foo
’. To allow completion of the second form:
_arguments -- -s "((#s)--enable- --disable-)"
Miscellaneous notes
Finally, note that _arguments
generally expects to be the primary
function handling any completion for which it is used. It may have side
effects which change the treatment of any matches added by other functions
called after it. To combine _arguments
with other functions, those
functions should be called either before _arguments
, as an action
within a spec, or in handlers for ‘->
state’ actions.
Here is a more general example of the use of _arguments
:
_arguments '-l+:left border:' \ '-format:paper size:(letter A4)' \ '*-copy:output file:_files::resolution:(300 600)' \ ':postscript file:_files -g \*.\(ps\|eps\)' \ '*:page number:'
This describes three options: ‘-l
’, ‘-format
’, and
‘-copy
’. The first takes one argument described as ‘left
border’ for which no completion will be offered because of the empty
action. Its argument may come directly after the ‘-l
’ or it may be
given as the next word on the line.
The ‘-format
’ option takes one
argument in the next word, described as ‘paper size’ for which
only the strings ‘letter
’ and ‘A4
’ will be completed.
The ‘-copy
’ option may appear more than once on the command line and
takes two arguments. The first is mandatory and will be completed as a
filename. The second is optional (because of the second colon before
the description ‘resolution’) and will be completed from the strings
‘300
’ and ‘600
’.
The last two descriptions say what should be completed as
arguments. The first describes the first argument as a
‘postscript file’ and makes files ending in ‘ps
’ or ‘eps
’
be completed. The last description gives all other arguments the
description ‘page number’ but does not offer completions.
_cache_invalid
cache_identifierThis function returns status zero if the completions cache corresponding to
the given cache identifier needs rebuilding. It determines this by
looking up the cache-policy
style for the current context.
This should provide a function name which is run with the full path to the
relevant cache file as the only argument.
Example:
_example_caching_policy () { # rebuild if cache is more than a week old local -a oldp oldp=( "$1"(Nm+7) ) (( $#oldp )) }
_call_function
return name [ arg ... ]If a function name exists, it is called with the arguments args. The return argument gives the name of a parameter in which the return status from the function name should be stored; if return is empty or a single hyphen it is ignored.
The return status of _call_function
itself is zero if the function
name exists and was called and non-zero otherwise.
_call_program
[ -l
] [ -p
] tag string ...This function provides a mechanism for the user to override the use of an
external command. It looks up the command
style with the supplied
tag. If the style is set, its value is used as the command to
execute. The strings from the call to _call_program
, or from the
style if set, are concatenated with spaces between them and the resulting
string is evaluated. The return status is the return status of the command
called.
By default, the command is run in an environment where all the locale
categories (except for LC_CTYPE
) are reset to ‘C
’ by calling the
utility function _comp_locale
(see below). If the option ‘-l
’ is
given, the command is run with the current locale.
If the option ‘-p
’ is supplied it indicates that the command
output is influenced by the permissions it is run with. If the
gain-privileges
style is set to true, _call_program
will make
use of commands such as sudo
, if present on the command-line, to
match the permissions to whatever the final command is likely to run
under. When looking up the gain-privileges
and command
styles,
the command component of the zstyle context will end with a slash
(‘/
’) followed by the command that would be used to gain privileges.
_combination
[ -s
pattern ] tag style spec ... field opts ...This function is used to complete combinations of values, for example pairs of hostnames and usernames. The style argument gives the style which defines the pairs; it is looked up in a context with the tag specified.
The style name consists of field names separated by hyphens, for example
‘users-hosts-ports
’. For each field for a value is already known, a
spec of the form ‘field=
pattern’ is given. For example,
if the command line so far specifies a user ‘pws
’, the argument
‘users=pws
’ should appear.
The next argument with no equals sign is taken as the name of the field for which completions should be generated (presumably not one of the fields for which the value is known).
The matches generated will be taken from the value of the style. These
should contain the possible values for the combinations in the appropriate
order (users, hosts, ports in the example above).
The values for the different fields are separated by colons. This
can be altered with the option -s
to _combination
which specifies a
pattern. Typically this is a character class, as for example
‘-s "[:@]"
’ in the case of the users-hosts
style. Each
‘field=
pattern’ specification restricts the
completions which apply to elements of the style with appropriately
matching fields.
If no style with the given name is defined for the given tag,
or if none of the strings in style’s value match, but a
function name of the required field preceded by an
underscore is defined, that function will be called to generate the
matches. For example, if there is no ‘users-hosts-ports
’ or no
matching hostname when a host is required, the function ‘_hosts
’ will
automatically be called.
If the same name is used for more than one field, in both the
‘field=
pattern’ and the argument that gives the name of the
field to be completed, the number of the field (starting with one) may
be given after the fieldname, separated from it by a colon.
All arguments after the required field name are passed to
compadd
when generating matches from the style value, or to
the functions for the fields if they are called.
_command_names
[ -e
| -
]This function completes words that are valid at command position: names of
aliases, builtins, hashed commands, functions, and so on. With the -e
flag, only hashed commands are completed. The -
flag is ignored.
_comp_locale
This function resets all the locale categories other than LC_CTYPE
to
‘C
’ so that the output from external commands can be easily analyzed by
the completion system. LC_CTYPE
retains the current value (taking
LC_ALL
and LANG
into account), ensuring that non-ASCII characters
in file names are still handled properly.
This function should normally be run only in a subshell, because the new
locale is exported to the environment. Typical usage would be
‘$(_comp_locale;
command ...)
’.
_completers
[ -p
]This function completes names of completers.
-p
Include the leading underscore (‘_
’) in the matches.
_default
This function corresponds to the -default-
special context which is
applied where no completion is defined. It is useful to call it under
certain error conditions such as completion after an unrecognised
subcommand. This applies the concept of graceful degradation to the
completion system, allowing it to fallback on basic completion of
commonly useful things like filenames.
_describe
[-12JVx
] [ -oO
| -t
tag ] descr name1 [ name2 ] [ opt ... ]
[ -
-
name1 [ name2 ] [ opt ... ] ... ]This function associates completions with descriptions.
Multiple groups separated by -
-
can be supplied, potentially with
different completion options opts.
The descr is taken as a string to display above the matches if the
format
style for the descriptions
tag is set. This is followed by
one or two names of arrays followed by options to pass to compadd
. The
array name1 contains the possible completions with their descriptions in
the form ‘completion:
description’. Any literal colons in
completion must be quoted with a backslash. If a name2 is
given, it should have the same number of elements as name1; in this
case the corresponding elements are added as possible completions instead
of the completion strings from name1. The completion list
will retain the descriptions from name1. Finally, a set of
completion options can appear.
If the option ‘-o
’ appears before the first argument, the matches added
will be treated as names of command options (N.B. not shell options),
typically following a ‘-
’, ‘-
-
’ or ‘+
’ on the command
line. In this case _describe
uses the prefix-hidden
,
prefix-needed
and verbose
styles to find out if the strings should
be added as completions and if the descriptions should be shown. Without
the ‘-o
’ option, only the verbose
style is used to decide how
descriptions are shown. If ‘-O
’ is used instead of ‘-o
’, command
options are completed as above but _describe
will not handle the
prefix-needed
style.
With the -t
option a tag can be specified. The default is
‘values
’ or, if the -o
option is given, ‘options
’.
The options -1
, -2
, -J
, -V
, -x
are passed to
_next_label
.
If selected by the list-grouped
style, strings with the same
description will appear together in the list.
_describe
uses the _all_labels
function to generate the matches, so
it does not need to appear inside a loop over tag labels.
_description
[ -x
] [ -12VJ
] tag name descr [ spec ... ]This function is not to be confused with the previous one; it is used as
a helper function for creating options to compadd
. It is buried
inside many of the higher level completion functions and so often does
not need to be called directly.
The styles listed below are tested in the current context using the
given tag. The resulting options for compadd
are put into the
array named name (this is traditionally ‘expl
’, but this
convention is not enforced). The description for the corresponding set
of matches is passed to the function in descr.
The styles tested are: format
, hidden
, matcher
,
ignore-line
, ignored-patterns
, group-name
and sort
.
The format
style is first tested for the given tag and then for
the descriptions
tag if no value was found, while the remainder are
only tested for the tag given as the first argument. The function also
calls _setup
which tests some more styles.
The string returned by the format
style (if any) will be modified so
that the sequence ‘%d
’ is replaced by the descr given as the third
argument without any leading or trailing white space. If, after
removing the white space, the descr is the empty string, the format
style will not be used and the options put into the name array will
not contain an explanation string to be displayed above the matches.
If _description
is called with more than three arguments,
the additional specs should be of the form ‘char:
str’.
These supply escape sequence replacements for the format
style:
every appearance of ‘%
char’ will be replaced by string.
If no additional specs are given but the description in descr
conforms to a common form then further escape sequences are set for
elements of that description. These elements correspond to a default
value (‘%o
’), the units (‘%m
’) range of acceptable values
(‘%r
’) and the remaining initial part of the description (‘%h
’).
The form the description takes consists of specifying the units and
range in parentheses and the default value in square brackets, for
example:
_description times expl 'timeout (seconds) (0-60) [20]'
It is possible to use zformat
conditional expressions when styling
these elements. So, for example, to add ‘default:
’ as a tag but only
when there is a default value to show, the format
style might
include ‘%(o.default: %o.)
’.
If the -x
option is given, the description will be passed to
compadd
using the -x
option instead of the default -X
. This
means that the description will be displayed even if there are no
corresponding matches.
The options placed in the array name take account of the
group-name
style, so matches are placed in a separate group where
necessary. The group normally has its elements sorted (by passing the
option -J
to compadd
), but if an option starting with ‘-V
’,
‘-J
’, ‘-1
’, or ‘-2
’ is passed to _description
, that
option will be included in the array. Hence it is possible for the
completion group to be unsorted by giving the option ‘-V
’,
‘-1V
’, or ‘-2V
’.
In most cases, the function will be used like this:
local expl _description files expl file compadd "$expl[@]" - "$files[@]"
Note the use of the parameter expl
, the hyphen, and the list of
matches. Almost all calls to compadd
within the completion system use
a similar format; this ensures that user-specified styles are correctly
passed down to the builtins which implement the internals of completion.
_dir_list
[ -s
sep ] [ -S
]Complete a list of directory names separated by colons
(the same format as $PATH
).
-s
sepUse sep as separator between items.
sep defaults to a colon (‘:
’).
-S
Add sep instead of slash (‘/
’) as an autoremoveable suffix.
_dispatch
context string ...This sets the current context to context and looks for completion
functions to handle this context by hunting through the list of command
names or special contexts (as described above for compdef
)
given as strings. The first completion function to be defined
for one of the contexts in the list is used to generate matches.
Typically, the last string is -default-
to cause the function
for default completion to be used as a fallback.
The function sets the parameter
$service
to the string being tried, and sets
the context/command field (the fourth) of the $curcontext
parameter to the context given as the first argument.
_email_addresses
[ -c
] [ -n
plugin ]Complete email addresses. Addresses are provided by plugins.
-c
Complete bare localhost@domain.tld
addresses, without a name part or
a comment.
Without this option, RFC822 ‘Firstname Lastname <
address>
’
strings are completed.
-n
pluginComplete aliases from plugin.
The following plugins are available by default:
_email-ldap
(see the filter
style),
_email-local
(completes user@
hostname Unix addresses),
_email-mail
(completes aliases from ~/.mailrc
),
_email-mush
,
_email-mutt
,
and
_email-pine
.
Addresses from the _email-
foo plugin are added under the
tag ‘email-
foo’.
Writing plugins
Plugins are written as separate functions with names starting with ‘_email-
’.
They are invoked with the -c
option and compadd
options.
They should either do their own completion or
set the $reply
array to a list of ‘alias:
address’ elements and return 300
.
New plugins will be picked up and run automatically.
_files
The function _files
is a wrapper around _path_files
. It supports
all of the same functionality, with some enhancements — notably, it
respects the list-dirs-first
style, and it allows users to override
the behaviour of the -g
and -/
options with the file-patterns
style. _files
should therefore be preferred over _path_files
in
most cases.
This function accepts the full set of options allowed by
_path_files
, described below.
_gnu_generic
This function is a simple wrapper around the _arguments
function
described above. It can be used to determine automatically the long
options understood by commands that produce a list when passed the
option ‘-
-help
’. It is intended to be used as a top-level
completion function in its own right. For example, to enable option
completion for the commands foo
and bar
, use
compdef _gnu_generic foo bar
after the call to compinit
.
The completion system as supplied is conservative in its use of this
function, since it is important to be sure the command understands the
option ‘-
-help
’.
_guard
[ options ] pattern descrThis function displays descr if pattern matches the string to
be completed. It is intended to be used in the action for the
specifications passed to _arguments
and similar functions.
The return status is zero if the message was displayed and the word to complete is not empty, and non-zero otherwise.
The pattern may be preceded by any of the options understood by
compadd
that are passed down from _description
, namely -M
,
-J
, -V
, -1
, -2
, -n
, -F
and -X
. All of these
options will be ignored. This fits in conveniently with the
argument-passing conventions of actions for _arguments
.
As an example, consider a command taking the options -n
and
-none
, where -n
must be followed by a numeric value in the
same word. By using:
_arguments '-n-: :_guard "[0-9]#" "numeric value"' '-none'
_arguments
can be made to both display the message ‘numeric
value
’ and complete options after ‘-n<TAB>
’. If the ‘-n
’ is
already followed by one or more digits (the pattern passed to
_guard
) only the message will be displayed; if the ‘-n
’ is
followed by another character, only options are completed.
_message
[ -r12
] [ -VJ
group ] descr_message -e
[ tag ] descrThe descr is used in the same way as the third
argument to the _description
function, except that the resulting
string will always be shown whether or not matches were
generated. This is useful for displaying a help message in places where
no completions can be generated.
The format
style is examined with the messages
tag to find a
message; the usual tag, descriptions
, is used only if the style is
not set with the former.
If the -r
option is given, no style is used; the descr is
taken literally as the string to display. This is most useful
when the descr comes from a pre-processed argument list
which already contains an expanded description. Note that this
option does not disable the ‘%
’-sequence parsing done by
compadd
.
The -12VJ
options and the group are passed to compadd
and
hence determine the group the message string is added to.
The second -e
form gives a description for completions with the tag
tag to be shown even if there are no matches for that tag. This form
is called by _arguments
in the event that there is no action for an
option specification. The tag can be omitted and if so the tag is taken
from the parameter $curtag
; this is maintained by the completion
system and so is usually correct. Note that if there are no matches at
the time this function is called, compstate[insert]
is cleared, so
additional matches generated later are not inserted on the command line.
_multi_parts
[ -i
] sep arrayThe argument sep is a separator character.
The array may be either the
name of an array parameter or a literal array in the form
‘(foo bar
)
’, a parenthesised list of words separated
by whitespace. The possible completions are the
strings from the array. However, each chunk delimited by sep will be
completed separately. For example, the _tar
function uses
‘_multi_parts
/
patharray’ to complete partial file paths
from the given array of complete file paths.
The -i
option causes _multi_parts
to insert a unique match even
if that requires multiple separators to be inserted. This is not usually
the expected behaviour with filenames, but certain other types of
completion, for example those with a fixed set of possibilities, may be
more suited to this form.
Like other utility functions, this function accepts the ‘-V
’,
‘-J
’, ‘-1
’, ‘-2
’, ‘-n
’, ‘-f
’, ‘-X
’, ‘-M
’,
‘-P
’, ‘-S
’, ‘-r
’, ‘-R
’, and ‘-q
’ options and passes
them to the compadd
builtin.
_next_label
[ -x
] [ -12VJ
] tag name descr [ option ... ]This function is used to implement the loop over different tag
labels for a particular tag as described above for the tag-order
style. On each call it checks to see if there are any more tag labels; if
there is it returns status zero, otherwise non-zero.
As this function requires a current tag to be set, it must always follow
a call to _tags
or _requested
.
The -x12VJ
options and the first three arguments are passed to the
_description
function. Where appropriate the tag will be
replaced by a tag label in this call. Any description given in
the tag-order
style is preferred to the descr passed to
_next_label
.
The options given after the descr
are set in the parameter given by name, and hence are to be passed
to compadd
or whatever function is called to add the matches.
Here is a typical use of this function for the tag foo
. The call to
_requested
determines if tag foo
is required at all; the loop
over _next_label
handles any labels defined for the tag in the
tag-order
style.
local expl ret=1 ... if _requested foo; then ... while _next_label foo expl '...'; do compadd "$expl[@]" ... && ret=0 done ... fi return ret
_normal
[ -P
| -p
precommand ]This is the standard function called to handle completion outside
any special -
context-
. It is called both to complete the command
word and also the arguments for a command. In the second case,
_normal
looks for a special completion for that command, and if
there is none it uses the completion for the -default-
context.
A second use is to reexamine the command line specified by the $words
array and the $CURRENT
parameter after those have been modified.
For example, the function _precommand
, which
completes after precommand specifiers such as nohup
, removes the
first word from the words
array, decrements the CURRENT
parameter,
then calls ‘_normal -p $service
’. The effect is that
‘nohup
cmd ...’ is treated in the same way as ‘cmd ...’.
-P
Reset the list of precommands. This option should be used if completing
a command line which allows internal commands (e.g. builtins and
functions) regardless of prior precommands (e.g. ‘zsh -c
’).
-p
precommandAppend precommand to the list of precommands. This option should be
used in nearly all cases in which -P
is not applicable.
If the command name matches one of the patterns given by one of the
options -p
or -P
to compdef
, the corresponding completion
function is called and then the parameter _compskip
is
checked. If it is set completion is terminated at that point even if
no matches have been found. This is the same effect as in the
-first-
context.
_numbers
[ option ... ] [ description ] [ suffix ... ]This can be used where a number is followed by a suffix to indicate the units. The unit suffixes are completed and can also be included in the description used when completion is invoked for the preceding number.
In addition to common compadd
options, _numbers
accepts the following
options:
-t
tagSpecify a tag to use instead of the default of numbers
.
-u
unitsIndicate the default units for the number, e.g. bytes
.
-l
minSpecify the lowest possible value for the number.
-m
maxSpecify the highest possible value for the number.
-d
defaultSpecify the default value.
-N
Allow negative numbers. This is implied if the range includes a negative.
-f
Allow decimal numbers.
Where a particular suffix represents the default units for a number, it should be prefixed with a colon. Additionally, suffixes can be followed by a colon and a description. So for example, the following allows the age of something to be specified, either in seconds or with an optional suffix with a longer unit of time:
_numbers -u seconds age :s:seconds m:minutes h:hours d:days
It is typically helpful for units to be presented in order of magnitude when completed. To facilitate this, the order in which they are given is preserved.
When the format
style is looked up with the descriptions
tag or
the tag specified with -t
, the list of suffixes is available as a
‘%x
’ escape sequence. This is in addition to the usual sequences
documented under the format
style. The form this list takes can also
be configured. To this end, the format
style is first looked up with
the tag unit-suffixes
. The retrieved format is applied to each
suffix in turn and the results are then concatenated to form the
completed list. For the unit-suffixes
format, ‘%x
’ expands to
the individual suffix and ‘%X
’ to its description. %d
’ indicates
a default suffix and can be used in a condition. The index and reverse
index are set in ‘%i
’ and ‘%r
’ respectively and are useful for
text included only with the first and last suffixes in the list. So for
example, the following joins the suffixes together as a comma-separated
list:
zstyle ':completion:*:unit-suffixes' format '%x%(r::,)'
_options
This can be used to complete the names of shell options. It provides a
matcher specification that ignores a leading ‘no
’, ignores
underscores and allows upper-case letters to
match their lower-case counterparts (for example, ‘glob
’,
‘noglob
’, ‘NO_GLOB
’ are all completed). Any arguments
are propagated to the compadd
builtin.
_options_set
and _options_unset
These functions complete only set or unset options, with the same
matching specification used in the _options
function.
Note that you need to uncomment a few lines in the _main_complete
function for these functions to work properly. The lines in question
are used to store the option settings in effect before the completion
widget locally sets the options it needs. Hence these functions are not
generally used by the completion system.
_parameters
This is used to complete the names of shell parameters.
The option ‘-g
pattern’ limits the completion to parameters
whose type matches the pattern. The type of a parameter is that
shown by ‘print ${(t)
param}
’, hence judicious use of
‘*
’ in pattern is probably necessary.
All other arguments are passed to the compadd
builtin.
_path_files
This function is used throughout the completion system
to complete filenames. It allows completion of partial paths. For
example, the string ‘/u/i/s/sig
’ may be completed to
‘/usr/include/sys/signal.h
’.
The options accepted by both _path_files
and _files
are:
-f
Complete all filenames. This is the default.
-/
Specifies that only directories should be completed.
-g
patternSpecifies that only files matching the pattern should be completed.
-W
pathsSpecifies path prefixes that are to be prepended to the string from the command line to generate the filenames but that should not be inserted as completions nor shown in completion listings. Here, paths may be the name of an array parameter, a literal list of paths enclosed in parentheses or an absolute pathname.
-F
ignored-filesThis behaves as for the corresponding option to the compadd
builtin.
It gives direct control over which
filenames should be ignored. If the option is not present, the
ignored-patterns
style is used.
Both _path_files
and _files
also accept the following options
which are passed to compadd
: ‘-J
’, ‘-V
’,
‘-1
’, ‘-2
’, ‘-n
’, ‘-X
’, ‘-M
’, ‘-P
’, ‘-S
’,
‘-q
’, ‘-r
’, and ‘-R
’.
Finally, the _path_files
function uses the styles expand
,
ambiguous
, special-dirs
, list-suffixes
and file-sort
described above.
_pick_variant
[ -b
builtin-label ] [ -c
command ] [ -r
name ]
label=
pattern ... label [ arg ... ]This function is used to resolve situations where a single command name requires more than one type of handling, either because it has more than one variant or because there is a name clash between two different commands.
The command to run is taken from the first element of the array
words
unless this is overridden by the option -c
. This command
is run and its output is compared with a series of patterns. Arguments
to be passed to the command can be specified at the end after all the
other arguments. The patterns to try in order are given by the arguments
label=
pattern; if the output of ‘command arg
...’ contains pattern, then label is selected as the label
for the command variant. If none of the patterns match, the final
command label is selected and status 1 is returned.
If the ‘-b
builtin-label’ is given, the command is tested to
see if it is provided as a shell builtin, possibly autoloaded; if so,
the label builtin-label is selected as the label for the variant.
If the ‘-r
name’ is given, the label picked is stored in
the parameter named name.
The results are also cached in the _cmd_variant
associative array
indexed by the name of the command run.
_regex_arguments
name spec ...This function generates a completion function name which matches
the specifications specs, a set of regular expressions as
described below. After running _regex_arguments
, the function
name should be called as a normal completion function.
The pattern to be matched is given by the contents of
the words
array up to the current cursor position joined together
with null characters; no quotation is applied.
The arguments are grouped as sets of alternatives separated by ‘|
’,
which are tried one after the other until one matches. Each alternative
consists of a one or more specifications which are tried left to right,
with each pattern matched being stripped in turn from the command line
being tested, until all of the group succeeds or until one fails; in the
latter case, the next alternative is tried. This structure can be
repeated to arbitrary depth by using parentheses; matching proceeds from
inside to outside.
A special procedure is applied if no test succeeds but the remaining
command line string contains no null character (implying the remaining
word is the one for which completions are to be generated). The
completion target is restricted to the remaining word and any
actions for the corresponding patterns are executed. In this case,
nothing is stripped from the command line string. The order of
evaluation of the actions can be determined by the tag-order
style; the various formats supported by _alternative
can be used
in action. The descr is used for setting up the array
parameter expl
.
Specification arguments take one of following forms, in which
metacharacters such as ‘(
’, ‘)
’, ‘#
’ and ‘|
’
should be quoted.
/
pattern/
[%
lookahead%
] [-
guard] [:
tag:
descr:
action]This is a single primitive component.
The function tests whether the combined pattern
‘(#b)((#B)
pattern)
lookahead*
’ matches
the command line string. If so, ‘guard’ is evaluated and
its return status is examined to determine if the test has succeeded.
The pattern string ‘[]
’ is guaranteed never to match.
The lookahead is not stripped from the command line before the next
pattern is examined.
The argument starting with :
is used in the same manner as an argument to
_alternative
.
A component is used as follows: pattern is tested to see if the component already exists on the command line. If it does, any following specifications are examined to find something to complete. If a component is reached but no such pattern exists yet on the command line, the string containing the action is used to generate matches to insert at that point.
/
pattern/+
[%
lookahead%
] [-
guard] [:
tag:
descr:
action]This is similar to ‘/
pattern/
...’ but the left part of the
command line string (i.e. the part already matched by previous patterns)
is also considered part of the completion target.
/
pattern/-
[%
lookahead%
] [-
guard] [:
tag:
descr:
action]This is similar to ‘/
pattern/
...’ but the actions of the
current and previously matched patterns are ignored even if the
following ‘pattern’ matches the empty string.
(
spec )
Parentheses may be used to groups specs; note each parenthesis
is a single argument to _regex_arguments
.
#
This allows any number of repetitions of spec.
The two specs are to be matched one after the other as described above.
|
specEither of the two specs can be matched.
The function _regex_words
can be used as a helper function to
generate matches for a set of alternative words possibly with
their own arguments as a command line argument.
Examples:
_regex_arguments _tst /$'[^\0]#\0'/ \ /$'[^\0]#\0'/ :'compadd aaa'
This generates a function _tst
that completes aaa
as its only
argument. The tag and description for the action have been
omitted for brevity (this works but is not recommended in normal use).
The first component matches the command word, which is arbitrary; the
second matches any argument. As the argument is also arbitrary, any
following component would not depend on aaa
being present.
_regex_arguments _tst /$'[^\0]#\0'/ \ /$'aaa\0'/ :'compadd aaa'
This is a more typical use; it is similar, but any following patterns
would only match if aaa
was present as the first argument.
_regex_arguments _tst /$'[^\0]#\0'/ \( \ /$'aaa\0'/ :'compadd aaa' \ /$'bbb\0'/ :'compadd bbb' \) \#
In this example, an indefinite number of command arguments may be
completed. Odd arguments are completed as aaa
and even arguments
as bbb
. Completion fails unless the set of aaa
and bbb
arguments before the current one is matched correctly.
_regex_arguments _tst /$'[^\0]#\0'/ \ \( /$'aaa\0'/ :'compadd aaa' \| \ /$'bbb\0'/ :'compadd bbb' \) \#
This is similar, but either aaa
or bbb
may be completed for
any argument. In this case _regex_words
could be used to generate
a suitable expression for the arguments.
_regex_words
tag description spec ...This function can be used to generate arguments for the
_regex_arguments
command which may be inserted at any point where
a set of rules is expected. The tag and description give a
standard tag and description pertaining to the current context. Each
spec contains two or three arguments separated by a colon: note
that there is no leading colon in this case.
Each spec gives one of a set of words that may be completed at
this point, together with arguments. It is thus roughly equivalent to
the _arguments
function when used in normal (non-regex) completion.
The part of the spec before the first colon is the word to be
completed. This may contain a *
; the entire word, before and after
the *
is completed, but only the text before the *
is required
for the context to be matched, so that further arguments may be
completed after the abbreviated form.
The second part of spec is a description for the word being completed.
The optional third part of the spec describes how words following the one being completed are themselves to be completed. It will be evaluated in order to avoid problems with quoting. This means that typically it contains a reference to an array containing previously generated regex arguments.
The option -t
term specifies a terminator for the word
instead of the usual space. This is handled as an auto-removable suffix
in the manner of the option -s
sep to _values
.
The result of the processing by _regex_words
is placed in the array
reply
, which should be made local to the calling function.
If the set of words and arguments may be matched repeatedly, a #
should be appended to the generated array at that point.
For example:
local -a reply _regex_words mydb-commands 'mydb commands' \ 'add:add an entry to mydb:$mydb_add_cmds' \ 'show:show entries in mydb' _regex_arguments _mydb "$reply[@]" _mydb "$@"
This shows a completion function for a command mydb
which takes
two command arguments, add
and show
. show
takes no arguments,
while the arguments for add
have already been prepared in an
array mydb_add_cmds
, quite possibly by a previous call to
_regex_words
.
_requested
[ -x
] [ -12VJ
] tag [ name descr [ command [ arg ... ] ]This function is called to decide whether a tag already registered by a
call to _tags
(see below) has been requested by the user and hence
completion should be performed for it. It returns status zero if the
tag is requested and non-zero otherwise. The function is typically used
as part of a loop over different tags as follows:
_tags foo bar baz while _tags; do if _requested foo; then ... # perform completion for foo fi ... # test the tags bar and baz in the same way ... # exit loop if matches were generated done
Note that the test for whether matches were generated is not performed
until the end of the _tags
loop. This is so that the user can set
the tag-order
style to specify a set of tags to be completed at the
same time.
If name and descr are given, _requested
calls the
_description
function with these arguments together with the options
passed to _requested
.
If command is given, the _all_labels
function will be called
immediately with the same arguments. In simple cases this makes it
possible to perform the test for the tag and the matching in one go.
For example:
local expl ret=1 _tags foo bar baz while _tags; do _requested foo expl 'description' \ compadd foobar foobaz && ret=0 ... (( ret )) || break done
If the command is not compadd
, it must nevertheless be prepared
to handle the same options.
_retrieve_cache
cache_identifierThis function retrieves completion information from the file given by
cache_identifier, stored in a directory specified by the
cache-path
style which defaults to ~/.zcompcache
. The return status
is zero if retrieval was successful. It will only attempt retrieval
if the use-cache
style is set, so you can call this function
without worrying about whether the user wanted to use the caching
layer.
See _store_cache
below for more details.
_sep_parts
This function is passed alternating arrays and separators as arguments.
The arrays specify completions for parts of strings to be separated by the
separators. The arrays may be the names of array parameters or
a quoted list of words in parentheses. For example, with the array
‘hosts=(ftp news)
’ the call ‘_sep_parts '(foo bar)' @ hosts
’ will
complete the string ‘f
’ to ‘foo
’ and the string ‘b@n
’ to
‘bar@news
’.
This function accepts the compadd
options ‘-V
’, ‘-J
’,
‘-1
’, ‘-2
’, ‘-n
’, ‘-X
’, ‘-M
’, ‘-P
’, ‘-S
’,
‘-r
’, ‘-R
’, and ‘-q
’ and passes them on to the compadd
builtin used to add the matches.
_sequence
[ -s
sep ] [ -n
max ] [ -d
] function [ -
] ...This function is a wrapper to other functions for completing items in a
separated list. The same function is used to complete each item in the
list. The separator is specified with the -s
option. If -s
is
omitted it will use ‘,
’. Duplicate values are not matched unless
-d
is specified. If there is a fixed or maximum number of items in
the list, this can be specified with the -n
option.
Common compadd
options are passed on to the function. It is possible
to use compadd
directly with _sequence
, though _values
may
be more appropriate in this situation.
_setup
tag [ group ]This function sets up the special
parameters used by the completion system appropriately for the tag
given as the first argument. It uses the styles list-colors
,
list-packed
, list-rows-first
, last-prompt
, accept-exact
,
menu
and force-list
.
The optional group supplies the name of the group in which the matches will be placed. If it is not given, the tag is used as the group name.
This function is called automatically from _description
and hence is not normally called explicitly.
_store_cache
cache_identifier param ...This function, together with _retrieve_cache
and
_cache_invalid
, implements a caching layer which can be used
in any completion function. Data obtained by
costly operations are stored in parameters;
this function then dumps the values of those parameters to a file. The
data can then be retrieved quickly from that file via _retrieve_cache
,
even in different instances of the shell.
The cache_identifier specifies the file which the data should be
dumped to. The file is stored in a directory specified by the
cache-path
style which defaults to ~/.zcompcache
. The remaining
params arguments are the parameters to dump to the file.
The return status is zero if storage was successful. The function will
only attempt storage if the use-cache
style is set, so you can
call this function without worrying about whether the user wanted to
use the caching layer.
The completion function may avoid calling _retrieve_cache
when it
already has the completion data available as parameters.
However, in that case it should
call _cache_invalid
to check whether the data in the parameters and
in the cache are still valid.
See the _perl_modules completion function for a simple example of the usage of the caching layer.
_tags
[ [ -C
name ] tag ... ]If called with arguments, these are taken to be the names of tags
valid for completions in the current context. These tags are stored
internally and sorted by using the tag-order
style.
Next, _tags
is called repeatedly without arguments from the same
completion function. This successively selects the first, second,
etc. set of tags requested by the user. The return status is zero if at
least one of the tags is requested and non-zero otherwise. To test if a
particular tag is to be tried, the _requested
function should be
called (see above).
If ‘-C
name’ is given, name is temporarily stored in the
argument field (the fifth) of the context in the curcontext
parameter
during the call to _tags
; the field is restored on exit. This
allows _tags
to use a more
specific context without having to change and reset the
curcontext
parameter (which has the same effect).
_tilde_files
Like _files
, but resolve leading tildes according to the rules of
filename expansion, so the suggested completions don’t start with
a ‘~
’ even if the filename on the command-line does.
_values
[ -O
name ] [ -s
sep ] [ -S
sep ] [ -wC
] desc spec ...This is used to complete arbitrary keywords (values) and their arguments, or lists of such combinations.
If the first argument is the option ‘-O
name’, it will be used
in the same way as by the _arguments
function. In other words, the
elements of the name array will be passed to compadd
when executing an action.
If the first argument (or the first argument after ‘-O
name’)
is ‘-s
’, the next argument is used as the character that separates
multiple values. This character is automatically added after each value
in an auto-removable fashion (see below); all values completed by
‘_values -s
’ appear in the same word on the command line, unlike
completion using _arguments
. If this option is not present, only a
single value will be completed per word.
Normally, _values
will only use the current word to determine
which values are already present on the command line and hence are not
to be completed again. If the -w
option is given, other arguments
are examined as well.
The first non-option argument, desc, is used as a string to print as a description before listing the values.
All other arguments describe the possible values and their
arguments in the same format used for the description of options by
the _arguments
function (see above). The only differences are that
no minus or plus sign is required at the beginning,
values can have only one argument, and the forms of action
beginning with an equal sign are not supported.
The character separating a value from its argument can be set using the
option -S
(like -s
, followed by the character to use as the
separator in the next argument). By default the equals
sign will be used as the separator between values and arguments.
Example:
_values -s , 'description' \ '*foo[bar]' \ '(two)*one[number]:first count:' \ 'two[another number]::second count:(1 2 3)'
This describes three possible values: ‘foo
’, ‘one
’, and
‘two
’. The first is described as ‘bar
’, takes no argument
and may appear more than once. The second is described as
‘number
’, may appear more than once, and takes one mandatory
argument described as ‘first count
’; no action is
specified, so it will not be completed. The
‘(two)
’ at the beginning says that if the value ‘one
’ is on
the line, the value ‘two
’ will no longer be considered a possible
completion. Finally, the last value (‘two
’) is described
as ‘another number
’ and takes an optional argument described as
‘second count
’ for which the completions (to appear after an
‘=
’) are ‘1
’, ‘2
’, and ‘3
’. The _values
function
will complete lists of these values separated by commas.
Like _arguments
, this function temporarily adds another context name
component to the arguments element (the fifth) of the current context
while executing the action. Here this name is just the name of the
value for which the argument is completed.
The style verbose
is used to decide if the descriptions for the
values (but not those for the arguments) should be printed.
The associative array val_args
is used to report values and their
arguments; this works similarly to the opt_args
associative array
used by _arguments
. Hence the function calling _values
should
declare the local parameters state
, state_descr
, line
,
context
and val_args
:
local context state state_descr line typeset -A val_args
when using an action of the form ‘->
string’. With this
function the context
parameter will be set to the name of the
value whose argument is to be completed. Note that for _values
,
the state
and state_descr
are scalars rather than arrays.
Only a single matching state is returned.
Note also that _values
normally adds the character used as the
separator between values as an auto-removable suffix (similar to a
‘/
’ after a directory). However, this is not possible for a
‘->
string’ action as the matches for the argument are
generated by the calling function. To get the usual behaviour,
the calling function can add the separator x as a suffix by
passing the options ‘-qS
x’ either directly or indirectly to
compadd
.
The option -C
is treated in the same way as it is by _arguments
.
In that case the parameter curcontext
should be made local instead
of context
(as described above).
_wanted
[ -x
] [ -C
name ] [ -12VJ
] tag name descr command [ arg ...]In many contexts, completion can only generate one particular set of matches, usually corresponding to a single tag. However, it is still necessary to decide whether the user requires matches of this type. This function is useful in such a case.
The arguments to _wanted
are the same as those to _requested
,
i.e. arguments to be passed to _description
. However, in this case
the command is not optional; all the processing of tags, including
the loop over both tags and tag labels and the generation of matches,
is carried out automatically by _wanted
.
Hence to offer only one tag and immediately add the corresponding matches with the given description:
local expl _wanted tag expl 'description' \ compadd -- match1 match2...
See also the use of _wanted
in the example function in
Dynamic named directories.
Note that, as for _requested
, the command must be able to
accept options to be passed down to compadd
.
Like _tags
this function supports the -C
option to give a
different name for the argument context field. The -x
option has
the same meaning as for _description
.
_widgets
[ -g
pattern ]This function completes names of zle widgets (see
Zle Widgets). The pattern, if present, is matched against values of the $widgets
special parameter, documented in
The zsh/zleparameter Module.