This describes the shell code for the `new' completion system, referred to as compsys. It is written in shell functions based on the features described in zshcompwid(1).
The features are contextual, sensitive to the point at which completion is started. Many completions are already provided. For this reason, a user can perform a great many tasks without knowing any details beyond how to initialize the system, which is described below in INITIALIZATION.
The context that decides what completion is to be performed may be
A full context specification contains other elements, as we shall describe.
Besides commands names and contexts, the system employs two more concepts, styles and tags. These provide ways for the user to configure the system's behaviour.
Tags play a dual role. They serve as a classification system for the matches, typically indicating a class of object that the user may need to distinguish. For example, when completing arguments of the ls command the user may prefer to try files before directories, so both of these are tags. They also appear as the rightmost element in a context specification.
Styles modify various operations of the completion system, such as output formatting, but also what kinds of completers are used (and in what order), or which tags are examined. Styles may accept arguments and are manipulated using the zstyle command described in see zshmodules(1).
In summary, tags describe what the completion objects are, and style how they are to be completed. At various points of execution, the completion system checks what styles and/or tags are defined for the current context, and uses that to modify its behavior. The full description of context handling, which determines how tags and other elements of the context influence the behaviour of styles, is described below in COMPLETION SYSTEM CONFIGURATION.
When a completion is requested, a dispatcher function is called; see the description of _main_complete in the list of control functions below. This dispatcher decides which function should be called to produce the completions, and calls it. The result is passed to one or more completers, functions that implement individual completion strategies: simple completion, error correction, completion with error correction, menu selection, etc.
More generally, the shell functions contained in the completion system are of two types:
If the system was installed completely, it should be enough to call the shell function compinit from your initialization file; see the next section. However, the function compinstall can be run by a user to configure various aspects of the completion system.
Usually, compinstall will insert code into .zshrc, although if that is not writable it will save it in another file and tell you that file's location. Note that it is up to you to make sure that the lines added to .zshrc are actually run; you may, for example, need to move them to an earlier place in the file if .zshrc usually returns early. So long as you keep them all together (including the comment lines at the start and finish), you can rerun compinstall and it will correctly locate and modify these lines. Note, however, that any code you add to this section by hand is likely to be lost if you rerun compinstall, although lines using the command `zstyle' should be gracefully handled.
The new code will take effect next time you start the shell, or run .zshrc by hand; there is also an option to make them take effect immediately. However, if compinstall has removed definitions, you will need to restart the shell to see the changes.
To run compinstall you will need to make sure it is in a directory mentioned in your fpath parameter, which should already be the case if zsh was properly configured as long as your startup files do not remove the appropriate directories from fpath. Then it must be autoloaded (`autoload -U compinstall' is recommended). You can abort the installation any time you are being prompted for information, and your .zshrc will not be altered at all; changes only take place right at the end, where you are specifically asked for confirmation.
This section describes the use of compinit to initialize completion for the current session when called directly; if you have run compinstall it will be called automatically from your .zshrc.
To initialize the system, the function compinit should be in a directory mentioned in the fpath parameter, and should be autoloaded (`autoload -U compinit' is recommended), and then run simply as `compinit'. This will define a few utility functions, arrange for all the necessary shell functions to be autoloaded, and will then re-define all widgets that do completion to use the new system. If you use the menu-select widget, which is part of the zsh/complist module, you should make sure that that module is loaded before the call to compinit so that that widget is also re-defined. If completion styles (see below) are set up to perform expansion as well as completion by default, and the TAB key is bound to expand-or-complete, compinit will rebind it to complete-word; this is necessary to use the correct form of expansion.
Should you need to use the original completion commands, you can still bind keys to the old widgets by putting a `.' in front of the widget name, e.g. `.expand-or-complete'.
To speed up the running of compinit, it can be made to produce a dumped configuration that will be read in on future invocations; this is the default, but can be turned off by calling compinit with the option -D. The dumped file is .zcompdump in the same directory as the startup files (i.e. $ZDOTDIR or $HOME); alternatively, an explicit file name can be given by `compinit -d dumpfile'. The next invocation of compinit will read the dumped file instead of performing a full initialization.
If the number of completion files changes, compinit will recognise this and produce a new dump file. However, if the name of a function or the arguments in the first line of a #compdef function (as described below) change, it is easiest to delete the dump file by hand so that compinit will re-create it the next time it is run. The check performed to see if there are new functions can be omitted by giving the option -C. In this case the dump file will only be created if there isn't one already.
The dumping is actually done by another function, compdump, but you will only need to run this yourself if you change the configuration (e.g. using compdef) and then want to dump the new one. The name of the old dumped file will be remembered for this purpose.
If the parameter _compdir is set, compinit uses it as a directory where completion functions can be found; this is only necessary if they are not already in the function search path.
For security reasons compinit also checks if the completion system would use files not owned by root or by the current user, or files in directories that are world- or group-writable or that are not owned by root or by the current user. If such files or directories are found, compinit will ask if the completion system should really be used. To avoid these tests and make all files found be used without asking, use the option -u, and to make compinit silently ignore all insecure files and directories use the option -i. This security check is skipped entirely when the -C option is given.
The security check can be retried at any time by running the function compaudit. This is the same check used by compinit, but when it is executed directly any changes to fpath are made local to the function so they do not persist. The directories to be checked may be passed as arguments; if none are given, compaudit uses fpath and _compdir to find completion system directories, adding missing ones to fpath as necessary. To force a check of exactly the directories currently named in fpath, set _compdir to an empty string before calling compaudit or compinit.
The function bashcompinit compatibility with bash's programmable completion system. When run it will define the functions, compgen and complete which correspond to the bash builtins with the same names. It will then be possible to use completion specifications and functions written for bash.
The convention for autoloaded functions used in completion is that they start with an underscore; as already mentioned, the fpath/FPATH parameter must contain the directory in which they are stored. If zsh was properly installed on your system, then fpath/FPATH automatically contains the required directories for the standard functions.
For incomplete installations, if compinit does not find enough files beginning with an underscore (fewer than twenty) in the search path, it will try to find more by adding the directory _compdir to the search path. If that directory has a subdirectory named Base, all subdirectories will be added to the path. Furthermore, if the subdirectory Base has a subdirectory named Core, compinit will add all subdirectories of the subdirectories is to the path: this allows the functions to be in the same format as in the zsh source distribution.
When compinit is run, it searches all such files accessible via fpath/FPATH and reads the first line of each of them. This line should contain one of the tags described below. Files whose first line does not start with one of these tags are not considered to be part of the completion system and will not be treated specially.
The tags are:
Each name may also be of the form `cmd=service'. When completing the command cmd, the function typically behaves as if the command (or special context) service was being completed instead. This provides a way of altering the behaviour of functions that can perform many different completions. It is implemented by setting the parameter $service when calling the function; the function may choose to interpret this how it wishes, and simpler functions will probably ignore it.
If the #compdef line contains one of the options -p or -P, the words following are taken to be patterns. The function will be called when completion is attempted for a command or context that matches one of the patterns. The options -p and -P are used to specify patterns to be tried before or after other completions respectively. Hence -P may be used to specify default actions.
The option -N is used after a list following -p or -P; it specifies that remaining words no longer define patterns. It is possible to toggle between the three options as many times as necessary.
When one of the key-sequences is typed, the function in the file will be invoked to generate the matches. Note that a key will not be re-bound if if it already was (that is, was bound to something other than undefined-key). The widget created has the same name as the file and can be bound to any other keys using bindkey as usual.
#compdef -K _foo_complete complete-word "^X^C" \ _foo_list list-choices "^X^D"
(all on one line) defines a widget _foo_complete for completion, bound to `^X^C', and a widget _foo_list for listing, bound to `^X^D'.
The # is part of the tag name and no white space is allowed after it. The #compdef tags use the compdef function described below; the main difference is that the name of the function is supplied implicitly.
The special contexts for which completion functions can be defined are:
Default implementations are supplied for each of these contexts. In most cases the context -context- is implemented by a corresponding function _context, for example the context `-tilde-' and the function `_tilde').
The contexts -redirect- and -value- allow extra context-specific information. (Internally, this is handled by the functions for each context calling the function _dispatch.) The extra information is added separated by commas.
For the -redirect- context, the extra information is in the form `-redirect-,op,command', where op is the redirection operator and command is the name of the command on the line. If there is no command on the line yet, the command field will be empty.
For the -value- context, the form is `-value-,name,command', where name is the name of the parameter. In the case of elements of an associative array, for example `assoc=(key <TAB>', name is expanded to `name-key'. In certain special contexts, such as completing after `make CFLAGS=', the command part gives the name of the command, here make; otherwise it is empty.
It is not necessary to define fully specific completions as the functions provided will try to generate completions by progressively replacing the elements with `-default-'. For example, when completing after `foo=<TAB>', _value will try the names `-value-,foo,' (note the empty command part), `-value-,foo,-default-' and`-value-,-default-,-default-', in that order, until it finds a function to handle the context.
As an example:
compdef '_files -g "*.log"' '-redirect-,2>,-default-'
completes files matching `*.log' after `2> <TAB>' for any command with no more specific handler defined.
Also:
compdef _foo -value-,-default-,-default-
specifies that _foo provides completions for the values of parameters for which no special function has been defined. This is usually handled by the function _value itself.
The same lookup rules are used when looking up styles (as described below); for example
zstyle ':completion:*:*:-redirect-,2>,*:*' file-patterns '*.log'
is another way to make completion after `2> <TAB>' complete files matching `*.log'.
The following function is defined by compinit and may be called directly.
Alternatively, all the arguments may have the form `cmd=service'. Here service should already have been defined by `cmd1=service' lines in #compdef files, as described above. The argument for cmd will be completed in the same way as service.
The function argument may alternatively be a string containing any shell code. The string will be executed using the eval builtin command to generate completions. This provides a way of avoiding having to define a new completion function. For example, to complete files ending in `.h' as arguments to the command foo:
compdef '_files -g "*.h"' foo
The option -n prevents any completions already defined for the command or context from being overwritten.
The option -d deletes any completion defined for the command or contexts listed.
The names may also contain -p, -P and -N options as described for the #compdef tag. The effect on the argument list is identical, switching between definitions of patterns tried initially, patterns tried finally, and normal commands and contexts.
The parameter $_compskip may be set by any function defined for a pattern context. If it is set to a value containing the substring `patterns' none of the pattern-functions will be called; if it is set to a value containing the substring `all', no other function will be called.
The form with -k defines a widget with the same name as the function that will be called for each of the key-sequences; this is like the #compdef -k tag. The function should generate the completions needed and will otherwise behave like the builtin widget whose name is given as the style argument. The widgets usable for this are: complete-word, delete-char-or-list, expand-or-complete, expand-or-complete-prefix, list-choices, menu-complete, menu-expand-or-complete, and reverse-menu-complete, as well as menu-select if the zsh/complist module is loaded. The option -n prevents the key being bound if it is already to bound to something other than undefined-key.
The form with -K is similar and defines multiple widgets based on the same function, each of which requires the set of three arguments name, style and key-sequences, where the latter two are as for -k and the first must be a unique widget name beginning with an underscore.
Wherever applicable, the -a option makes the function autoloadable, equivalent to autoload -U function.
The function compdef can be used to associate existing completion functions with new commands. For example,
compdef _pids foo
uses the function _pids to complete process IDs for the command foo.
Note also the _gnu_generic function described below, which can be used to complete options for commands that understand the `--help' option.
This section gives a short overview of how the completion system works, and then more detail on how users can configure how and when matches are generated.
When completion is attempted somewhere on the command line the completion system first works out the context. This takes account of a number of things including the command word (such as `grep' or `zsh') and options to which the current word may be an argument (such as the `-o' option to zsh which takes a shell option as an argument).
This context information is condensed into a string consisting of multiple fields separated by colons, referred to simply as `the context' in the remainder of the documentation. This is used to look up styles, context-sensitive options that can be used to configure the completion system. The context used for lookup may vary during the same call to the completion system.
The context string always consists of a fixed set of fields, separated by colons and with a leading colon before the first, in the form :completion:function:completer:command:argument:tag. These have the following meaning:
The context is gradually put together as the functions are executed, starting with the main entry point, which adds :completion: and the function element if necessary. The completer then adds the completer element. The contextual completion adds the command and argument options. Finally, the tag is added when the types of completion are known. For example, the context name
:completion::complete:dvips:option-o-1:files
says that normal completion was attempted as the first argument to the option -o of the command dvips:
dvips -o ...
and the completion function will generate filenames.
Usually completion will be tried for all possible tags in an order given by the completion function. However, this can be altered by using the tag-order style. Completion is then restricted to the list of given tags in the given order.
The _complete_help bindable command shows all the contexts and tags available for completion at a particular point. This provides an easy way of finding information for tag-order and other styles. It is described in the section `Bindable Commands' below.
Styles determine such things as how the matches are generated, similarly to shell options but with much more control. They can have any number of strings as their value. They are defined with the zstyle builtin command (see zshmodules(1)).
When looking up styles the completion system uses full context names, including the tag. Looking up the value of a style therefore consists of two things: the context, which may be matched as a pattern, and the name of the style itself, which must be given exactly.
For example, many completion functions can generate matches in a simple and a verbose form and use the verbose style to decide which form should be used. To make all such functions use the verbose form, put
zstyle ':completion:*' verbose yes
in a startup file (probably .zshrc). This gives the verbose style the value yes in every context inside the completion system, unless that context has a more specific definition. It is best to avoid giving the context as `*' in case the style has some meaning outside the completion system.
Many such general purpose styles can be configured simply by using the compinstall function.
A more specific example of the use of the verbose style is by the completion for the kill builtin. If the style is set, the builtin lists full job texts and process command lines; otherwise it shows the bare job numbers and PIDs. To turn the style off for this use only:
zstyle ':completion:*:*:kill:*' verbose no
For even more control, the style can use one of the tags `jobs' or `processes'. To turn off verbose display only for jobs:
zstyle ':completion:*:*:kill:*:jobs' verbose no
The -e option to zstyle even allows completion function code to appear as the argument to a style; this requires some understanding of the internals of completion functions (see see zshcompwid(1))). For example,
zstyle -e ':completion:*' hosts 'reply=($myhosts)'
This forces the value of the hosts style to be read from the variable myhosts each time a host name is needed; this is useful if the value of myhosts can change dynamically. For another useful example, see the example in the description of the file-list style below. This form can be slow and should be avoided for commonly examined styles such as menu and list-rows-first.
Note that the order in which styles are defined does not matter; the style mechanism uses the most specific possible match for a particular style to determine the set of values. More precisely, strings are preferred over patterns (for example, `:completion::complete:foo' is more specific than `:completion::complete:*'), and longer patterns are preferred over shorter patterns.
Style names like those of tags are arbitrary and depend on the completion function. However, the following two sections list some of the most common tags and styles.
Some of the following are only used when looking up particular styles and do not refer to a type of match.
Note that the values of several of these styles represent boolean values. Any of the strings `true', `on', `yes', and `1' can be used for the value `true' and any of the strings `false', `off', `no', and `0' for the value `false'. The behavior for any other value is undefined except where explicitly mentioned. The default value may be either true or false if the style is not set.
Some of these styles are tested first for every possible tag corresponding to a type of match, and if no style was found, for the default tag. The most notable styles of this type are menu, list-colors and styles controlling completion listing such as list-packed and last-prompt). When tested for the default tag, only the function field of the context will be set so that a style using the default tag will normally be defined along the lines of:
zstyle ':completion:*:default' menu ...
When completing pathnames (where the tag used is `paths') this style accepts any number of patterns as the value in addition to the boolean values. Pathnames matching one of these patterns will be accepted immediately even if the command line contains some more partially typed pathname components and these match no file under the directory accepted.
This style is also used by the _expand completer to decide if words beginning with a tilde or parameter expansion should be expanded. For example, if there are parameters foo and foobar, the string `$foo' will only be expanded if accept-exact is set to `true'; otherwise the completion system will be allowed to complete $foo to $foobar. If the style is set to `continue', _expand will add the expansion as a match and the completion system will also be allowed to continue.
When this style is true, any prefix of a path that matches an existing directory is accepted without any attempt to complete it further. Hence, in the given example, the path /usr/bin/ is accepted immediately and completion tried in that directory.
The _prefix completer uses this style as a simple boolean value to decide if a space should be inserted before the suffix.
The default is to complete lists when the word on the line already contains a colon.
The default value for this style is `_expand _old_list _correct _approximate', i.e. it contains the completers for which a string with all matches will almost never be wanted.
As an example, the completion function for process IDs uses this style with the processes tag to generate the IDs to complete and the list of processes to display (if the verbose style is `true'). The list produced by the command should look like the output of the ps command. The first line is not displayed, but is searched for the string `PID' (or `pid') to find the position of the process IDs in the following lines. If the line does not contain `PID', the first numbers in each of the other lines are taken as the process IDs to complete.
Note that the completion function generally has to call the specified command for each attempt to generate the completion list. Hence care should be taken to specify only commands that take a short time to run, and in particular to avoid any that may never terminate.
Each string may be either the name of a completer function or a string of the form `function:name'. In the first case the completer field of the context will contain the name of the completer without the leading underscore and with all other underscores replaced by hyphens. In the second case the function is the name of the completer to call, but the context will contain the user-defined name in the completer field of the context. If the name starts with a hyphen, the string for the context will be build from the name of the completer function as in the first case with the name appended to it. For example:
zstyle ':completion:*' completer _complete _complete:-foo
Here, completion will call the _complete completer twice, once using `complete' and once using `complete-foo' in the completer field of the context. Normally, using the same completer more than once only makes sense when used with the `functions:name' form, because otherwise the context name will be the same in all calls to the completer; possible exceptions to this rule are the _ignored and _prefix completers.
The default value for this style is `_complete _ignored': only completion will be done, first using the ignored-patterns style and the $fignore array and then without ignoring matches.
zstyle :complete:sudo: environ \ PATH="/sbin:/usr/sbin:$PATH" HOME="/root"
If one of its values is the string `prefix', the partially typed word from the line will be expanded as far as possible even if trailing parts cannot be completed.
If one of its values is the string `suffix', matching names for components after the first ambiguous one will also be added. This means that the resulting string is the longest unambiguous string possible. However, menu completion can be used to cycle through all matches.
It is important to use a sufficiently restrictive context when specifying fake strings. Note that the styles fake-files and fake-parameters provide additional features when completing files or parameters.
The following shows a way of supplementing any tag with arbitrary data, but having it behave for display purposes like a separate tag. In this example we use the features of the tag-order style to divide the named-directories tag into two when performing completion with the standard completer complete for arguments of cd. The tag named-directories-normal behaves as normal, but the tag named-directories-mine contains a fixed set of directories. This has the effect of adding the match group `extra directories' with the given completions.
zstyle ':completion::complete:cd:*' tag-order \ 'named-directories:-mine:extra\ directories named-directories:-normal:named\ directories *' zstyle ':completion::complete:cd:*:named-directories-mine' \ fake-always mydir1 mydir2 zstyle ':completion::complete:cd:*:named-directories-mine' \ ignored-patterns '*'
This can be useful on systems that support special filesystems whose top-level pathnames can not be listed or generated with glob patterns. It can also be used for directories for which one does not have read permission.
The pattern form can be used to add a certain `magic' entry to all directories on a particular filing system.
zmodload -i zsh/stat disable stat
The style may either be set to a true value (or `all'), or one of the values `insert' or `list', indicating that files are to be listed in long format in all circumstances, or when attempting to insert a file name, or when listing file names without attempting to insert one.
More generally, the value may be an array of any of the above values, optionally followed by =num. If num is present it gives the maximum number of matches for which long listing style will be used. For example,
zstyle ':completion:*' file-list list=20 insert=10
specifies that long format will be used when listing up to 20 files or inserting a file with up to 10 matches (assuming a listing is to be shown at all, for example on an ambiguous completion), else short format will be used.
zstyle -e ':completion:*' file-list '(( ${+NUMERIC} )) && reply=(true)'
specifies that long format will be used any time a numeric argument is supplied, else short format.
The file-patterns style provides alternatives to the default tags, which are not used. Its value consists of elements of the form `pattern:tag'; each string may contain any number of such specifications separated by spaces.
The pattern is a pattern that is to be used to generate filenames. Any occurrence of the sequence `%p' is replaced by any pattern(s) passed by the function calling _files. Colons in the pattern must be preceded by a backslash to make them distinguishable from the colon before the tag. If more than one pattern is needed, the patterns can be given inside braces, separated by commas.
The tags of all strings in the value will be offered by _files and used when looking up other styles. Any tags in the same word will be offered at the same time and before later words. If no `:tag' is given the `files' tag will be used.
The tag may also be followed by an optional second colon and a description, which will be used for the `%d' in the value of the format style (if that is set) instead of the default description supplied by the completion function. If the description given here contains itself a `%d', that is replaced with the description supplied by the completion function.
For example, to make the rm command first complete only names of object files and then the names of all files if there is no matching object file:
zstyle ':completion:*:*:rm:*' file-patterns \
'*.o:object-files' '%p:all-files'
To alter the default behaviour of file completion -- offer files matching a pattern and directories on the first attempt, then all files -- to offer only matching files on the first attempt, then directories, and finally all files:
zstyle ':completion:*' file-patterns \
'%p:globbed-files' '*(-/):directories' '*:all-files'
This works even where there is no special pattern: _files matches all files using the pattern `*' at the first step and stops when it sees this pattern. Note also it will never try a pattern more than once for a single completion attempt.
During the execution of completion functions, the EXTENDED_GLOB option is in effect, so the characters `#', `~' and `^' have special meanings in the patterns.
This style is tested for the default tag as well as for each tag valid for the current completion. Hence the listing can be forced only for certain types of match.
The style is tested with each tag valid for the current completion before it is tested for the descriptions tag. Hence different format strings can be defined for different types of match.
Note also that some completer functions define additional `%'-sequences. These are described for the completer functions that make use of them.
Some completion functions display messages that may be customised by setting this style for the messages tag. Here, the `%d' is replaced with a message given by the completion function.
Finally, the format string is looked up with the warnings tag, for use when no matches could be generated at all. In this case the `%d' is replaced with the descriptions for the matches that were expected separated by spaces. The sequence `%D' is replaced with the same descriptions separated by newlines.
It is possible to use printf-style field width specifiers with `%d' and similar escape sequences. This is handled by the zformat builtin command from the zsh/zutil module, see zshmodules(1).
zstyle ':completion:*:*:-command-:*:commands' group-name commands zstyle ':completion:*:*:-command-:*:functions' group-name functions
As a consequence, any match with the same tag will be displayed in the same group.
If the name given is the empty string the name of the tag for the matches will be used as the name of the group. So, to have all different types of matches displayed separately, one can just set:
zstyle ':completion:*' group-name ''
All matches for which no group name is defined will be put in a group named -default-.
For example, to have names of builtin commands, shell functions and external commands appear in that order when completing in command position:
zstyle ':completion:*:*:-command-:*' group-order \
builtins functions commands
Note that the matches will still be completed; they are just not shown in the list. To avoid having matches considered as possible completions at all, the tag-order style can be modified as described below.
The values `current' and `current-shown' are a bit like the opposite of the accept-exact style: only strings with missing characters will be completed.
Note that you almost certainly don't want to set this to `true' or `other' for a general context such as `:completion:*'. This is because it would disallow completion of, for example, options multiple times even if the command in question accepts the option more than once.
In addition, the value may include one or both of:
Excluded values act in a similar fashion to values of the ignored-patterns style, so they can be restored to consideration by the _ignored completer.
Note that the EXTENDED_GLOB option is set during the execution of completion functions, so the characters `#', `~' and `^' have special meanings in the patterns.
If the value of the style is `single', the shell will wait until the user has typed enough to make the command unique before converting the name to an ID; attempts at completion will be unsuccessful until that point. If the value is any other string, menu completion will be started when the string typed by the user is longer than the common prefix to the corresponding IDs.
The value may also contain the substrings `pending' or `pending=val'. In this case, the typed character will be inserted instead of staring completion when there is unprocessed input pending. If a val is given, completion will not be done if there are at least that many characters of unprocessed input. This is often useful when pasting characters into a terminal. Note however, that it relies on the $PENDING special parameter from the zsh/zle module being set properly which is not guaranteed on all platforms.
The default value of this style is `true' except for completion within vared builtin command where it is `false'.
In the case of the _approximate completer, the completer field in the context will already have been set to one of correct-num or approximate-num, where num is the number of errors that were accepted.
In the case of the _match completer, the style may also be set to the string `pattern'. Then the pattern on the line is left unchanged if it does not match unambiguously.
The behaviour of expand when this style is true is to cause _expand to give up when a single expansion with the restored prefix is the same as the original; hence any remaining completers may be called.
If this style is set for the default tag, the strings in the value are taken as specifications that are to be used everywhere. If it is set for other tags, the specifications are used only for matches of the type described by the tag. For this to work best, the group-name style must be set to an empty string.
In addition to setting styles for specific tags, it is also possible to use group names specified explicitly by the group-name tag together with the `(group)' syntax allowed by the ZLS_COLORS and ZLS_COLOURS parameters and simply using the default tag.
It is possible to use any color specifications already set up for the GNU version of the ls command:
zstyle ':completion:*:default' list-colors ${(s.:.)LS_COLORS}
The default colors are the same as for the GNU ls command and can be obtained by setting the style to an empty string (i.e. '').
The value may contain the escape sequences: `%l' or `%L', which will be replaced by the number of the last line displayed and the total number of lines; `%m' or `%M', the number of the last match shown and the total number of matches; and `%p' and `%P', `Top' when at the beginning of the list, `Bottom' when at the end and the position shown as a percentage of the total length otherwise. In each case the form with the uppercase letter will be replaced by a string of fixed width, padded to the right with spaces, while the lowercase form will be replaced by a variable width string. As in other prompt strings, the escape sequences `%S', `%s', `%B', `%b', `%U', `%u' for entering and leaving the display modes standout, bold and underline, and `%F', `%f', `%K', `%k' for changing the foreground background colour, are also available, as is the form `%{...%}' for enclosing escape sequences which display with zero (or, with a numeric argument, some other) width.
After deleting this prompt the variable LISTPROMPT should be unset for the the removal to take effect.
For example:
zstyle ':completion:*' local toast \
/var/http/public/toast public_html
Completion after `http://toast/stuff/' will look for files in the directory /var/http/public/toast/stuff, while completion after `http://toast/~yousir/' will look for files in the directory ~yousir/public_html.
zstyle ':completion:*' matcher-list '' 'm:{a-zA-Z}={A-Za-z}'
By default each specification replaces the previous one; however, if a specification is prefixed with +, it is added to the existing list. Hence it is possible to create increasingly general specifications without repetition:
zstyle ':completion:*' matcher-list '' '+m{a-Z}={A-Z}' '+m{A-Z}={a-z}'
It is possible to create match specifications valid for particular completers by using the third field of the context. For example, to use the completers _complete and _prefix but only allow case-insensitive completion with _complete:
zstyle ':completion:*' completer _complete _prefix
zstyle ':completion:*:complete:*' matcher-list \
'' 'm:{a-zA-Z}={A-Za-z}'
User-defined names, as explained for the completer style, are available. This makes it possible to try the same completer more than once with different match specifications each time. For example, to try normal completion without a match specification, then normal completion with case-insensitive matching, then correction, and finally partial-word completion:
zstyle ':completion:*' completer _complete _correct _complete:foo
zstyle ':completion:*:complete:*' matcher-list \
'' 'm:{a-zA-Z}={A-Za-z}'
zstyle ':completion:*:foo:*' matcher-list \
'm:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*'
If the style is unset in any context no match specification is applied. Note also that some completers such as _correct and _approximate do not use the match specifications at all, though these completers will only ever called once even if the matcher-list contains more than one element.
Where multiple specifications are useful, note that the entire completion is done for each element of matcher-list, which can quickly reduce the shell's performance. As a rough rule of thumb, one to three strings will give acceptable performance. On the other hand, putting multiple space-separated values into the same string does not have an appreciable impact on performance.
If there is no current matcher or it is empty, and the option NO_CASE_GLOB is in effect, the matching for files is performed case-insensitively in any case. However, any matcher must explicitly specify case-insensitive matching if that is required.
If the value for this style contains the string `numeric', the completer function will take any numeric argument as the maximum number of errors allowed. For example, with
zstyle ':completion:*:approximate:::' max-errors 2 numeric
two errors are allowed if no numeric argument is given, but with a numeric argument of six (as in `ESC-6 TAB'), up to six errors are accepted. Hence with a value of `0 numeric', no correcting completion will be attempted unless a numeric argument is given.
If the value contains the string `not-numeric', the completer will not try to generate corrected completions when given a numeric argument, so in this case the number given should be greater than zero. For example, `2 not-numeric' specifies that correcting completion with two errors will usually be performed, but if a numeric argument is given, correcting completion will not be performed.
The default value for this style is `2 numeric'.
This has the most impact when several matches have the same description and so will be grouped together. Increasing the style will allow more matches to be grouped together; decreasing it will allow more of the description to be visible.
If none of the values found in this way is true but at least one is set to `auto', the shell behaves as if the AUTO_MENU option is set.
If one of the values is explicitly set to false, menu completion will be explicitly turned off, overriding the MENU_COMPLETE option and other settings.
In the form `yes=num', where `yes' may be any of the true values (`yes', `true', `on' and `1'), menu completion will be turned on if there are at least num matches. In the form `yes=long', menu completion will be turned on if the list does not fit on the screen. This does not activate menu completion if the widget normally only lists completions, but menu completion can be activated in that case with the value `yes=long-list' (Typically, the value `select=long-list' described later is more useful as it provides control over scrolling.)
Similarly, with any of the `false' values (as in `no=10'), menu completion will not be used if there are num or more matches.
The value of this widget also controls menu selection, as implemented by the zsh/complist module. The following values may appear either alongside or instead of the values above.
If the value contains the string `select', menu selection will be started unconditionally.
In the form `select=num', menu selection will only be started if there are at least num matches. If the values for more than one tag provide a number, the smallest number is taken.
Menu selection can be turned off explicitly by defining a value containing the string`no-select'.
It is also possible to start menu selection only if the list of matches does not fit on the screen by using the value `select=long'. To start menu selection even if the current widget only performs listing, use the value `select=long-list'.
To turn on menu completion or menu selection when a there are a certain number of matches or the list of matches does not fit on the screen, both of `yes=' and `select=' may be given twice, once with a number and once with `long' or `long-list'.
Finally, it is possible to activate two special modes of menu selection. The word `interactive' in the value causes interactive mode to be entered immediately when menu selection is started; see the description of the zsh/complist module in zshmodules(1) for a description of interactive mode. Including the string `search' does the same for incremental search mode. To select backward incremental search, include the string `search-backward'.
For example, suppose you type ^Xc to use the _correct_word widget, which generates a list of corrections for the word under the cursor. Usually, typing ^D would generate a standard list of completions for the word on the command line, and show that. With _oldlist, it will instead show the list of corrections already generated.
As another example consider the _match completer: with the insert-unambiguous style set to `true' it inserts only a common prefix string, if there is any. However, this may remove parts of the original pattern, so that further completion could produce more matches than on the first attempt. By using the _oldlist completer and setting this style to _match, the list of matches generated on the first attempt will be used again.
If this style is set it is generally unwise to call the _all_matches completer unconditionally. One possible use is for either this style or the completer style to be defined with the -e option to zstyle to make the style conditional.
For example, suppose you type ^Xc to generate a list of corrections, and menu completion is started in one of the usual ways. Usually, or with this style set to false, typing TAB at this point would start trying to complete the line as it now appears. With _oldlist, it instead continues to cycle through the list of corrections.
zstyle ':completion:*:complete:dpkg:option--status-1:*' \
packageset avail
causes available packages, rather than only installed packages, to be completed for `dpkg --status'.
The default value for this style is `false'.
The default value for this style is `true'.
If it is a singe number, only the last N words from the history will be completed.
If it is a range of the form `max:slice', the last slice words will be completed; then if that yields no matches, the slice words before those will be tried and so on. This process stops either when at least one match was been found, or max words have been tried.
The default is to complete all words from the history at once.
It is not always possible to know if connections are in fact to a remote site, so some may be prevented unnecessarily.
The style is tested first against the full context including the tag, and if that fails to produce a value against the context without the tag.
If the calling widget explicitly requests unsorted matches, this is usually honoured. However, the default (unsorted) behaviour of completion for the command history may be overridden by setting the style to true.
In the _expand completer, if it is set to `true', the expansions generated will always be sorted. If it is set to `menu', then the expansions are only sorted when they are offered as single strings but not in the string containing all possible expansions.
The following example sets special-dirs to `..' when the current prefix is empty, is a single `.', or consists only of a path beginning with `../'. Otherwise the value is `false'.
zstyle -e ':completion:*' special-dirs \ '[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)'
The default for this style is `false'.
The default is `true'.
The values for the style are sets of space-separated lists of tags. The tags in each value will be tried at the same time; if no match is found, the next value is used. (See the file-patterns style for an exception to this behavior.)
For example:
zstyle ':completion:*:complete:-command-:*' tag-order \
'commands functions'
specifies that completion in command position first offers external commands and shell functions. Remaining tags will be tried if no completions are found.
In addition to tag names, each string in the value may take one of the following forms:
If the label starts with a hyphen, the tag is prepended to the label to form the name used for lookup. This can be used to make the completion system try a certain tag more than once, supplying different style settings for each attempt; see below for an example.
In any of the forms above the tag may be a pattern or several patterns in the form `{pat1,pat2...}'. In this case all matching tags will be used except for any given explicitly in the same string.
One use of these features is to try one tag more than once, setting other styles differently on each attempt, but still to use all the other tags without having to repeat them all. For example, to make completion of function names in command position ignore all the completion functions starting with an underscore the first time completion is tried:
zstyle ':completion:*:*:-command-:*' tag-order \
'functions:-non-comp *' functions
zstyle ':completion:*:functions-non-comp' ignored-patterns '_*'
On the first attempt, all tags will be offered but the functions tag will be replaced by functions-non-comp. The ignored-patterns style is set for this tag to exclude functions starting with an underscore. If there are no matches, the second value of the tag-order style is used which completes functions using the default tag, this time presumably including all function names.
The matches for one tag can be split into different groups. For example:
zstyle ':completion:*' tag-order \
'options:-long:long\ options
options:-short:short\ options
options:-single-letter:single\ letter\ options'
zstyle ':completion:*:options-long' ignored-patterns '[-+](|-|[^-]*)'
zstyle ':completion:*:options-short' ignored-patterns '--*' '[-+]?'
zstyle ':completion:*:options-single-letter' ignored-patterns '???*'
With the group-names style set, options beginning with `--', options beginning with a single `-' or `+' but containing multiple characters, and single-letter options will be displayed in separate groups with different descriptions.
Another use of patterns is to try multiple match specifications one after another. The matcher-list style offers something similar, but it is tested very early in the completion system and hence can't be set for single commands nor for more specific contexts. Here is how to try normal completion without any match specification and, if that generates no matches, try again with case-insensitive matching, restricting the effect to arguments of the command foo:
zstyle ':completion:*:*:foo:*' tag-order '*' '*:-case'
zstyle ':completion:*-case' matcher 'm:{a-z}={A-Z}'
First, all the tags offered when completing after foo are tried using the normal tag name. If that generates no matches, the second value of tag-order is used, which tries all tags again except that this time each has -case appended to its name for lookup of styles. Hence this time the value for the matcher style from the second call to zstyle in the example is used to make completion case-insensitive.
It is possible to use the -e option of the zstyle builtin command to specify conditions for the use of particular tags. For example:
zstyle -e '*:-command-:*' tag-order '
if [[ -n $PREFIX$SUFFIX ]]; then
reply=( )
else
reply=( - )
fi'
Completion in command position will be attempted only if the string typed so far is not empty. This is tested using the PREFIX special parameter; see zshcompwid for a description of parameters which are special inside completion widgets. Setting reply to an empty array provides the default behaviour of trying all tags at once; setting it to an array containing only a hyphen disables the use of all tags and hence of all completions.
If no tag-order style has been defined for a context, the strings `(|*-)argument-* (|*-)option-* values' and `options' plus all tags offered by the completion function will be used to provide a sensible default behavior that causes arguments (whether normal command arguments or arguments of options) to be completed before option names for most commands.
If the value consists of more than one string, or if the only string does not name a file or directory, the strings are used as the URLs to complete.
If the value contains only one string which is the name of a normal file the URLs are taken from that file (where the URLs may be separated by white space or newlines).
Finally, if the only string in the value names a directory, the directory hierarchy rooted at this directory gives the completions. The top level directory should be the file access method, such as `http', `ftp', `bookmark' and so on. In many cases the next level of directories will be a filename. The directory hierarchy can descend as deep as necessary.
For example,
zstyle ':completion:*' urls ~/.urls mkdir -p ~/.urls/ftp/ftp.zsh.org/pub/development
allows completion of all the components of the URL ftp://ftp.zsh.org/pub/development after suitable commands such as `netscape' or `lynx'. Note, however, that access methods and files are completed separately, so if the hosts style is set hosts can be completed without reference to the urls style.
See the description in the function _urls itself for more information (e.g. `more $^fpath/_urls(N)').
Note that this is only intended to smooth the transition from compctl to the new completion system and may disappear in the future.
Note also that the definitions from compctl will only be used if there is no specific completion function for the command in question. For example, if there is a function _foo to complete arguments to the command foo, compctl will never be invoked for foo. However, the compctl version will be tried if foo only uses default completion.
Currently this is only used in completions for `make', but it may be extended depending on authorial frustration.
It is possible to group values for sets of commands which allow a remote login, such as rlogin and ssh, by using the my-accounts tag. Similarly, values for sets of commands which usually refer to the accounts of other people, such as talk and finger, can be grouped by using the other-accounts tag. More ambivalent commands may use the accounts tag.
The initialization script compinit redefines all the widgets which perform completion to call the supplied widget function _main_complete. This function acts as a wrapper calling the so-called `completer' functions that generate matches. If _main_complete is called with arguments, these are taken as the names of completer functions to be called in the order given. If no arguments are given, the set of functions to try is taken from the completer style. For example, to use normal completion and correction if that doesn't generate any matches:
zstyle ':completion:*' completer _complete _correct
after calling compinit. The default value for this style is `_complete _ignored', i.e. normally only ordinary completion is tried, first with the effect of the ignored-patterns style and then without it. The _main_complete function uses the return status of the completer functions to decide if other completers should be called. If the return status is zero, no other completers are tried and the _main_complete function returns.
If the first argument to _main_complete is a single hyphen, the arguments will not be taken as names of completers. Instead, the second argument gives a name to use in the completer field of the context and the other arguments give a command name and arguments to call to generate the matches.
The following completer functions are contained in the distribution, although users may write their own. Note that in contexts the leading underscore is stripped, for example basic completion is performed in the context `:completion::complete:...'.
It may be useful to use the _generic function described below to bind _all_matches to its own keystroke, for example:
zle -C all-matches complete-word _generic bindkey '^Xa' all-matches zstyle ':completion:all-matches:*' old-matches only zstyle ':completion:all-matches::::' completer _all_matches
Note that this does not generate completions by itself: first use any of the standard ways of generating a list of completions, then use ^Xa to show all matches. It is possible instead to add a standard completer to the list and request that the list of all matches should be directly inserted:
zstyle ':completion:all-matches::::' completer _all_matches _complete zstyle ':completion:all-matches:*' insert true
In this case the old-matches style should not be set.
zstyle ':completion:*' completer _complete _approximate
This will give correcting completion if and only if normal completion yields no possible completions. When corrected completions are found, the completer will normally start menu completion allowing you to cycle through these strings.
This completer uses the tags corrections and original when generating the possible corrections and the original string. The format style for the former may contain the additional sequences `%e' and `%o' which will be replaced by the number of errors accepted to generate the corrections and the original string, respectively.
The completer progressively increases the number of errors allowed up to the limit by the max-errors style, hence if a completion is found with one error, no completions with two errors will be shown, and so on. It modifies the completer name in the context to indicate the number of errors being tried: on the first try the completer field contains `approximate-1', on the second try `approximate-2', and so on.
When _approximate is called from another function, the number of errors to accept may be passed with the -a option. The argument is in the same format as the max-errors style, all in one string.
Note that this completer (and the _correct completer mentioned below) can be quite expensive to call, especially when a large number of errors are allowed. One way to avoid this is to set up the completer style using the -e option to zstyle so that some completers are only used when completion is attempted a second time on the same string, e.g.:
zstyle -e ':completion:*' completer '
if [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
_last_try="$HISTNO$BUFFER$CURSOR"
reply=(_complete _match _prefix)
else
reply=(_ignored _correct _approximate)
fi'
This uses the HISTNO parameter and the BUFFER and CURSOR special parameters that are available inside zle and completion widgets to find out if the command line hasn't changed since the last time completion was tried. Only then are the _ignored, _correct and _approximate completers called.
To complete arguments of commands, _complete uses the utility function _normal, which is in turn responsible for finding the particular function; it is described below. Various contexts of the form -context- are handled specifically. These are all mentioned above as possible arguments to the #compdef tag.
Before trying to find a function for a specific context, _complete checks if the parameter `compcontext' is set. Setting `compcontext' allows the usual completion dispatching to be overridden which is useful in places such as a function that uses vared for input. If it is set to an array, the elements are taken to be the possible matches which will be completed using the tag `values' and the description `value'. If it is set to an associative array, the keys are used as the possible completions and the values (if non-empty) are used as descriptions for the matches. If `compcontext' is set to a string containing colons, it should be of the form `tag:descr:action'. In this case the tag and descr give the tag and description to use and the action indicates what should be completed in one of the forms accepted by the _arguments utility function described below.
Finally, if `compcontext' is set to a string without colons, the value is taken as the name of the context to use and the function defined for that context will be called. For this purpose, there is a special context named -command-line- that completes whole command lines (commands and their arguments). This is not used by the completion system itself but is nonetheless handled when explicitly called.
For example, with:
zstyle ':completion:::::' completer _complete _correct _approximate zstyle ':completion:*:correct:::' max-errors 2 not-numeric zstyle ':completion:*:approximate:::' max-errors 3 numeric
correction will accept up to two errors. If a numeric argument is given, correction will not be performed, but correcting completion will be, and will accept as many errors as given by the numeric argument. Without a numeric argument, first correction and then correcting completion will be tried, with the first one accepting two errors and the second one accepting three errors.
When _correct is called as a function, the number of errors to accept may be given following the -a option. The argument is in the same form a values to the accept style, all in one string.
This completer function is intended to be used without the _approximate completer or, as in the example, just before it. Using it after the _approximate completer is useless since _approximate will at least generate the corrected strings generated by the _correct completer -- and probably more.
The tags used when generating expansions are all-expansions for the string containing all possible expansions, expansions when adding the possible expansions as single matches and original when adding the original string from the line. The order in which these strings are generated, if at all, can be controlled by the group-order and tag-order styles, as usual.
The format string for all-expansions and for expansions may contain the sequence `%o' which will be replaced by the original string from the line.
The kind of expansion to be tried is controlled by the substitute, glob and subst-globs-only styles.
It is also possible to call _expand as a function, in which case the different modes may be selected with options: -s for substitute, -g for glob and -o for subst-globs-only.
This function is also a bindable command, see the section `Bindable Commands' below.
Normally completion will be performed by taking the pattern from the line, inserting a `*' at the cursor position and comparing the resulting pattern with the possible completions generated. This can be modified with the match-original style described above.
The generated matches will be offered in a menu completion unless the insert-unambiguous style is set to `true'; see the description above for other options for this style.
Note that matcher specifications defined globally or used by the completion functions (the styles matcher-list and matcher) will not be used.
The completer style is used to decide which other completers are to be called to generate matches. If this style is unset, the list of completers set for the current context is used -- except, of course, the _prefix completer itself. Furthermore, if this completer appears more than once in the list of completers only those completers not already tried by the last invocation of _prefix will be called.
For example, consider this global completer style:
zstyle ':completion:*' completer \
_complete _prefix _correct _prefix:foo
Here, the _prefix completer tries normal completion but ignoring the suffix. If that doesn't generate any matches, and neither does the call to the _correct completer after it, _prefix will be called a second time and, now only trying correction with the suffix ignored. On the second invocation the completer part of the context appears as `foo'.
To use _prefix as the last resort and try only normal completion when it is invoked:
zstyle ':completion:*' completer _complete ... _prefix zstyle ':completion::prefix:*' completer _complete
The add-space style is also respected. If it is set to `true' then _prefix will insert a space between the matches generated (if any) and the suffix.
Note that this completer is only useful if the COMPLETE_IN_WORD option is set; otherwise, the cursor will be moved to the end of the current word before the completion code is called and hence there will be no suffix.
The expansion depends on the array style user-expand being defined for the current context; remember that the context for completers is less specific than that for contextual completion as the full context has not yet been determined. Elements of the array may have one of the following forms:
hash is the name of an associative array. Note this is not a full parameter expression, merely a $, suitably quoted to prevent immediate expansion, followed by the name of an associative array. If the trial expansion word matches a key in hash, the resulting expansion is the corresponding value.
_func is the name of a shell function whose name must begin with _ but is not otherwise special to the completion system. The function is called with the trial word as an argument. If the word is to be expanded, the function should set the array reply to a list of expansions. The return status of the function is irrelevant.
In addition to the context-dependent completions provided, which are expected to work in an intuitively obvious way, there are a few widgets implementing special behaviour which can be bound separately to keys. The following is a list of these and their default bindings.
for key in '!' '$' '@' '/' '~'; do bindkey "\e$key" _bash_complete-word bindkey "^X$key" _bash_list-choices done
This includes the bindings for `~' in case they were already bound to something else; the completion code does not override user bindings.
When used as a bindable command there is one additional feature that can be selected by setting the complete style to `true'. In this case, if the word is not the name of an alias, _expand_alias tries to complete the word to a full alias name without expanding it. It leaves the cursor directly after the completed word so that invoking _expand_alias once more will expand the now-complete alias name.
zle -C foo complete-word _generic bindkey '...' foo zstyle ':completion:foo:*' menu yes select=1
Note in particular that the completer style may be set for the context in order to change the set of functions used to generate possible matches. If _generic is called with arguments, those are passed through to _main_complete as the list of completers in place of those defined by the completer style.
Second, any other string will be passed as a set of arguments to compadd and should hence be an expression specifying what should be completed.
A very restricted set of editing commands is available when reading the string: `DEL' and `^H' delete the last character; `^U' deletes the line, and `^C' and `^G' abort the function, while `RET' accepts the completion. Note the string is used verbatim as a command line, so arguments must be quoted in accordance with standard shell rules.
Once a string has been read, the next call to _read_comp will use the existing string instead of reading a new one. To force a new string to be read, call _read_comp with a numeric argument.
Note that the information about styles may be incomplete; it depends on the information available from the completion functions called, which in turn is determined by the user's own styles and other settings.
If this widget is created using the name of the function, as it is by default, then when executed it will read a key sequence. This is expected to be bound to a call to a completion function that uses the _generic widget. That widget will be executed, and information provided in the same format that the _complete_help widget displays for contextual completion.
If the widget's name contains debug, for example if it is created as `zle -N _complete_debug_generic _complete_help_generic', it will read and execute the keystring for a generic widget as before, but then generate debugging information as done by _complete_debug for contextual completion.
If the widget's name contains noread, it will not read a keystring but instead arrange that the next use of a generic widget run in the same shell will have the effect as described above.
The widget works by setting the shell parameter ZSH_TRACE_GENERIC_WIDGET which is read by _generic. Unsetting the parameter cancels any pending effect of the noread form.
For example, after executing the following:
zle -N _complete_debug_generic _complete_help_generic bindkey '^x:' _complete_debug_generic
typing `C-x :' followed by the key sequence for a generic widget will cause trace output for that widget to be saved to a file.
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.
Two more features are offered by the _main_complete function. The arrays compprefuncs and comppostfuncs may contain names of functions that are to be called immediately before or after completion has been tried. A function will only be called once unless it explicitly reinserts itself into the array.
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.
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), excluding the `->state' and `=...' forms.
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 functions 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.
Like _tags this function supports the -C option to give a different name for the argument context field.
With the option -n, _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.
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.
By default, options are multi-character name, one `-word' per option. With -s, options may be single characters, with more than one option per word, although words starting with two hyphens, such as `--prefix', are still considered complete option names. This is suitable for standard GNU options.
The combination of -s with -w allows single-letter options to be combined in a single word even if one or more of the options take arguments. For example, if -a takes an argument, with no -s `-ab' is considered as a single (unhandled) option; with -s -ab is an option with the argument `b'; with both -s and -w, -ab may be the option -a and the option -b with arguments still to come.
The option -W takes this 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.
The following forms are available for the initial optspec, whether or not the option has arguments.
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.
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:
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.
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'.
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 forms for action are as follows.
:foo:(foo bar baz)
: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.
Where _arguments encounters a `->string', it will strip all leading and trailing whitespace from string and set the array state to the set of all stringss for which an action is to be performed.
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 $state, _arguments also sets the global parameters `context', `line' and `opt_args' as described below, and does not reset any changes made to the special parameters such as PREFIX and words. This gives the calling function the choice of resetting these parameters or propagating changes in them.
A function calling _arguments with at least one action containing a `->string' therefore must declare appropriate local parameters:
local context state line typeset -A opt_args
to avoid _arguments from altering the global environment.
This is most useful with one of the specifiers that restrict the words on the command line on which the action is to operate (the two- and three-colon forms above). One particular use is when an action itself causes _arguments on a restricted range; it is necessary to use this trick to insert an appropriate command name into the range for the second call to _arguments to be able to parse the line.
Otherwise it will be invoked with some extra strings placed after the first word; these are to be passed down as options to the compadd builtin. They ensure that the state specified by _arguments, in particular the descriptions of options and arguments, is correctly passed to the completion command. These additional arguments are taken from the array parameter `expl'; this will be set up before executing the action and hence may be referred to inside it, typically in an expansion of the form `$expl[@]' which preserves empty elements of the array.
During the performance of the action the array `line' will be set to the command name and normal arguments from the command line, i.e. the words from the command line 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. For options that have more than one argument these are given as one string, separated by colons. All colons in the original arguments are preceded with backslashes.
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.
It is possible to specify multiple sets of options and arguments with the sets separated by single hyphens. The specifications before the first hyphen (if any) are shared by all the remaining sets. The first word in every other set provides a name for the set which may appear in exclusion lists in specifications, either alone or before one of the possible values described above. In the second case a `-' should appear between this name and the remainder.
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.
If the name given for one of the mutually exclusive sets is of the form `(name)' then only one value from each set will ever be completed; more formally, all specifications are mutually exclusive to all other specifications in the same set. This is useful for defining multiple sets of options which are mutually exclusive and in which the options are aliases for each other. For example:
_arguments \
-a -b \
- '(compress)' \
{-c,--compress}'[compress]' \
- '(uncompress)' \
{-d,--decompress}'[decompress]'
As the completion code has to parse the command line separately for each set this form of argument is slow and 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.
The options -S and -A are available to simplify the specifications for commands with standard option parsing. With -S, no option will be completed after a `--' appearing on its own on the line; this argument will otherwise be ignored; hence in the line
foobar -a -- -b
the `-a' is considered an option but the `-b' is considered an argument, while the `--' is considered to be neither.
With -A, no options will be completed after the first non-option argument on the line. The -A must be followed by 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 "-*"'.
The option `-O name' specifies the name of an array whose elements will be passed as arguments to functions called to execute actions. For example, this can be used to pass the same set of options for the compadd builtin to all actions.
The option `-M spec' sets a match specification to use to completion option names and values. It must appear before the first argument specification. The default is `r:|[_-]=* r:|=*': this allows partial word completion after `_' and `-', for example `-f-b' can be completed to `-foo-bar'.
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.
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 specifiers of the form `pattern:message:action'; note that normal _arguments specifiers 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. 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 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 `=-'.
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. Each pair consists of a pattern and a replacement. For example, some configure-scripts describe options only as `--enable-foo', but also accept `--disable-foo'. To allow completion of the second form:
_arguments -- -s "(#--enable- --disable-)"
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 numbers' but does not offer completions.
Example:
_example_caching_policy () {
# rebuild if cache is more than a week old
local -a oldp
oldp=( "$1"(Nmw+1) )
(( $#oldp ))
}
The return status of _call_function itself is zero if the function name exists and was called and non-zero otherwise.
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 different fields 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.
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 first array 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 second array is given, it should have the same number of elements as the first; in this case the corresponding elements are added as possible completions instead of the completion strings from the first array. The completion list will retain the descriptions from the first array. 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'.
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.
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, ignored-patterns and group-name. 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 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.
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.
This function accepts the full set of options allowed by _path_files, described below.
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'.
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.
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.
The -12VJ options and the group are passed to compadd and hence determine the group the message string is added to.
The second form gives a description for completions with the tag tag to be shown even if there are no matches for that tag. The tag can be omitted and if so the tag is taken from the parameter $curtag; this is maintained by the completion system and so is usually correct.
The -i option causes _multi_parts to insert a unique match even if that requires multiple separators to be inserted. This is not usually the expected behaviour with filenames, but certain other types of completion, for example those with a fixed set of possibilities, may be more suited to this form.
Like other utility functions, this function accepts the `-V', `-J', `-1', `-2', `-n', `-f', `-X', `-M', `-P', `-S', `-r', `-R', and `-q' options and passes them to the compadd builtin.
The -x12VJ options and the first three arguments are passed to the _description function. Where appropriate the tag will be replaced by a tag label in this call. Any description given in the tag-order style is preferred to the descr passed to _next_label.
The options given after the descr are set in the parameter given by name, and hence are to be passed to compadd or whatever function is called to add the matches.
Here is a typical use of this function for the tag foo. The call to _requested determines if tag foo is required at all; the loop over _next_label handles any labels defined for the tag in the tag-order style.
local expl ret=1
...
if _requested foo; then
...
while _next_label foo expl '...'; do
compadd "$expl[@]" ... && ret=0
done
...
fi
return ret
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 pre-command specifiers such as nohup, removes the first word from the words array, decrements the CURRENT parameter, then calls _normal again. The effect is that `nohup cmd ...' is treated in the same way as `cmd ...'.
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.
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.
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.
The options accepted by both _path_files and _files are:
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.
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 args ...' 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 `-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.
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.
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.
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.
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.
_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.
See _store_cache below for more details.
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.
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.
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.
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).
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 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, line, context and val_args:
local context state 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 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 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).
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 matches...
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.
In the source distribution, the files are contained in various subdirectories of the Completion directory. They may have been installed in the same structure, or into one single function directory. The following is a description of the files found in the original directory structure. If you wish to alter an installed file, you will need to copy it to some directory which appears earlier in your fpath than the standard directory where it appears.