zshcompwid

ZSHCOMPWID(1)               General Commands Manual              ZSHCOMPWID(1)



NAME
       zshcompwid - zsh completion widgets

DESCRIPTION
       The shell's programmable completion mechanism can be manipulated in two
       ways; here the low-level features supporting the newer, function-based
       mechanism are defined.  A complete set of shell functions based on
       these features is described in zshcompsys(1), and users with no
       interest in adding to that system (or, potentially, writing their own
       -- see dictionary entry for `hubris') should skip the current section.
       The older system based on the compctl builtin command is described in
       zshcompctl(1).

       Completion widgets are defined by the -C option to the zle builtin
       command provided by the zsh/zle module (see zshzle(1)). For example,

              zle -C complete expand-or-complete completer

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

       When this newly defined widget is bound to a key using the bindkey
       builtin command defined in the zsh/zle module (see zshzle(1)), typing
       that key will call the shell function `completer'. This function is
       responsible for generating the possible matches using the builtins
       described below.  As with other ZLE widgets, the function is called
       with its standard input closed.

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

COMPLETION SPECIAL PARAMETERS
       The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE_SPACE_SUFFIX_CHARS are
       used by the completion mechanism, but are not special. See Parameters
       Used By The Shell in zshparam(1).

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

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

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

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

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

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

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

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

       QISUFFIX
              Like QIPREFIX, but containing the suffix.

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

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

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

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

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

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

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

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

                     condition
                            when completing inside a `[[...]]' conditional
                            expression; in this case the words array contains
                            only the words inside the conditional expression.

                     math   when completing in a mathematical environment such
                            as a `((...))' construct.

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

                     redirect
                            when completing after a redirection operator.

                     subscript
                            when completing inside a parameter subscript.

                     value  when completing the value of a parameter
                            assignment.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

              nmatches
                     The number of matches generated and accepted by the
                     completion code so far.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

COMPLETION BUILTIN COMMANDS
       compadd [ -akqQfenUl12C ] [ -F array ]
               [-P prefix ] [ -S suffix ]
               [-p hidden-prefix ] [ -s hidden-suffix ]
               [-i ignored-prefix ] [ -I ignored-suffix ]
               [-W file-prefix ] [ -d array ]
               [-J group-name ] [ -X explanation ] [ -x message ]
               [-V group-name ] [ -o [ order ] ]
               [-r remove-chars ] [ -R remove-func ]
               [-D array ] [ -O array ] [ -A array ]
               [-E number ]
               [-M match-spec ] [ -- ] [ words ... ]

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

              The completion code breaks the string to complete into seven
              fields in the order:

                     <ipre><apre><hpre><word><hsuf><asuf><isuf>

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

              The supported flags are:

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

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

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

              -s hidden-suffix
                     Like `-p', but gives a string to insert after the match.

              -i ignored-prefix
                     This gives a string to insert into the command line just
                     before any string given with the `-P' option.  Without
                     `-P' the string is inserted before the string given with
                     `-p' or directly before the match.

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

              -a     With this flag the words are taken as names of arrays and
                     the possible matches are their values.  If only some
                     elements of the arrays are needed, the words may also
                     contain subscripts, as in `foo[2,-1]'.

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

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

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

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

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

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

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

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

                     reverse
                            Arrange the matches backwards by reversing the
                            sort ordering.

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

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

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

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

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

                     Within the explanation, the following sequences may be
                     used to specify output attributes as described in the
                     section EXPANSION OF PROMPT SEQUENCES in zshmisc(1):
                     `%B', `%S', `%U', `%F', `%K' and their lower case
                     counterparts, as well as `%{...%}'.  `%F', `%K' and
                     `%{...%}' take arguments in the same form as prompt
                     expansion.  (Note that the sequence `%G' is not
                     available; an argument to `%{' should be used instead.)
                     The sequence `%%' produces a literal `%'.

                     These sequences are most often employed by users when
                     customising the format style (see zshcompsys(1)), but
                     they must also be taken into account when writing
                     completion functions, as passing descriptions with
                     unescaped `%' characters to utility functions such as
                     _arguments and _message may produce unexpected results.
                     If arbitrary text is to be passed in a description, it
                     can be escaped using e.g. ${my_str//\%/%%}.

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

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

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

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

              -R remove-func
                     This is another form of the -r option. When a suffix has
                     been inserted and the completion accepted, the function
                     remove-func will be called after the next character
                     typed.  It is passed the length of the suffix as an
                     argument and can use the special parameters available in
                     ordinary (non-completion) zle widgets (see zshzle(1)) to
                     analyse and modify the command line.

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

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

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

              -F array
                     Specifies an array containing patterns. Words matching
                     one of these patterns are ignored, i.e. not considered to
                     be possible matches.

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

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

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

              -n     Specifies that the words added are to be used as possible
                     matches, but are not to appear in the completion listing.

              -U     If this flag is given, all words given will be accepted
                     and no matching will be done by the completion code.
                     Normally this is used in functions that do the matching
                     themselves.

              -O array
                     If this option is given, the words are not added to the
                     set of possible completions.  Instead, matching is done
                     as usual and all of the words given as arguments that
                     match the string on the command line will be stored in
                     the array parameter whose name is given as array.

              -A array
                     As the -O option, except that instead of those of the
                     words which match being stored in array, the strings
                     generated internally by the completion code are stored.
                     For example, with a matching specification of `-M
                     "L:|no="', the string `nof' on the command line and the
                     string `foo' as one of the words, this option stores the
                     string `nofoo' in the array, whereas the -O option stores
                     the `foo' originally given.

              -D array
                     As with -O, the words are not added to the set of
                     possible completions.  Instead, the completion code tests
                     whether each word in turn matches what is on the line.
                     If the nth word does not match, the nth element of the
                     array is removed.  Elements for which the corresponding
                     word is matched are retained.

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

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

              -
              --     This flag ends the list of flags and options. All
                     arguments after it will be taken as the words to use as
                     matches even if they begin with hyphens.

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

       compset -p number
       compset -P [ number ] pattern
       compset -s number
       compset -S [ number ] pattern
       compset -n begin [ end ]
       compset -N beg-pat [ end-pat ]
       compset -q
              This command simplifies modification of the special parameters,
              while its return status allows tests on them to be carried out.

              The options are:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

COMPLETION MATCHING CONTROL
       It is possible by use of the -M option of the compadd builtin command
       to specify how the characters in the string to be completed (referred
       to here as the command line) map onto the characters in the list of
       matches produced by the completion code (referred to here as the trial
       completions). Note that this is not used if the command line contains a
       glob pattern and the GLOB_COMPLETE option is set or the pattern_match
       of the compstate special association is set to a non-empty string.

       The match-spec given as the argument to the -M option (see `Completion
       Builtin Commands' above) consists of one or more matching descriptions
       separated by whitespace.  Each description consists of a letter
       followed by a colon and then the patterns describing which character
       sequences on the line match which character sequences in the trial
       completion.  Any sequence of characters not handled in this fashion
       must match exactly, as usual.

       The forms of match-spec understood are as follows. In each case, the
       form with an upper case initial character retains the string already
       typed on the command line as the final result of completion, while with
       a lower case initial character the string on the command line is
       changed into the corresponding part of the trial completion.

       m:lpat=tpat
       M:lpat=tpat
              Here, lpat is a pattern that matches on the command line,
              corresponding to tpat which matches in the trial completion.

       l:lanchor|lpat=tpat
       L:lanchor|lpat=tpat
       l:lanchor||ranchor=tpat
       L:lanchor||ranchor=tpat
       b:lpat=tpat
       B:lpat=tpat
              These letters are for patterns that are anchored by another
              pattern on the left side. Matching for lpat and tpat is as for m
              and M, but the pattern lpat matched on the command line must be
              preceded by the pattern lanchor.  The lanchor can be blank to
              anchor the match to the start of the command line string;
              otherwise the anchor can occur anywhere, but must match in both
              the command line and trial completion strings.

              If no lpat is given but a ranchor is, this matches the gap
              between substrings matched by lanchor and ranchor. Unlike
              lanchor, the ranchor only needs to match the trial completion
              string.

              The b and B forms are similar to l and L with an empty anchor,
              but need to match only the beginning of the word on the command
              line or trial completion, respectively.

       r:lpat|ranchor=tpat
       R:lpat|ranchor=tpat
       r:lanchor||ranchor=tpat
       R:lanchor||ranchor=tpat
       e:lpat=tpat
       E:lpat=tpat
              As l, L, b and B, with the difference that the command line and
              trial completion patterns are anchored on the right side.  Here
              an empty ranchor and the e and E forms force the match to the
              end of the command line or trial completion string.

       x:     This form is used to mark the end of matching specifications:
              subsequent specifications are ignored. In a single standalone
              list of specifications this has no use but where matching
              specifications are accumulated, such as from nested function
              calls, it can allow one function to override another.

       Each lpat, tpat or anchor is either an empty string or consists of a
       sequence of literal characters (which may be quoted with a backslash),
       question marks, character classes, and correspondence classes; ordinary
       shell patterns are not used.  Literal characters match only themselves,
       question marks match any character, and character classes are formed as
       for globbing and match any character in the given set.

       Correspondence classes are defined like character classes, but with two
       differences: they are delimited by a pair of braces, and negated
       classes are not allowed, so the characters ! and ^ have no special
       meaning directly after the opening brace.  They indicate that a range
       of characters on the line match a range of characters in the trial
       completion, but (unlike ordinary character classes) paired according to
       the corresponding position in the sequence.  For example, to make any
       ASCII lower case letter on the line match the corresponding upper case
       letter in the trial completion, you can use `m:{a-z}={A-Z}' (however,
       see below for the recommended form for this).  More than one pair of
       classes can occur, in which case the first class before the =
       corresponds to the first after it, and so on.  If one side has more
       such classes than the other side, the superfluous classes behave like
       normal character classes.  In anchor patterns correspondence classes
       also behave like normal character classes.

       The standard `[:name:]' forms described for standard shell patterns
       (see the section FILENAME GENERATION in zshexpn(1)) may appear in
       correspondence classes as well as normal character classes.  The only
       special behaviour in correspondence classes is if the form on the left
       and the form on the right are each one of [:upper:], [:lower:].  In
       these cases the character in the word and the character on the line
       must be the same up to a difference in case.  Hence to make any lower
       case character on the line match the corresponding upper case character
       in the trial completion you can use `m:{[:lower:]}={[:upper:]}'.
       Although the matching system does not yet handle multibyte characters,
       this is likely to be a future extension, at which point this syntax
       will handle arbitrary alphabets; hence this form, rather than the use
       of explicit ranges, is the recommended form.  In other cases `[:name:]'
       forms are allowed.  If the two forms on the left and right are the
       same, the characters must match exactly.  In remaining cases, the
       corresponding tests are applied to both characters, but they are not
       otherwise constrained; any matching character in one set goes with any
       matching character in the other set:  this is equivalent to the
       behaviour of ordinary character classes.

       The pattern tpat may also be one or two stars, `*' or `**'. This means
       that the pattern on the command line can match any number of characters
       in the trial completion. In this case the pattern must be anchored (on
       either side); in the case of a single star, the anchor then determines
       how much of the trial completion is to be included -- only the
       characters up to the next appearance of the anchor will be matched.
       With two stars, substrings matched by the anchor can be matched, too.

       Examples:

       The keys of the options association defined by the parameter module are
       the option names in all-lower-case form, without underscores, and
       without the optional no at the beginning even though the builtins
       setopt and unsetopt understand option names with upper case letters,
       underscores, and the optional no.  The following alters the matching
       rules so that the prefix no and any underscore are ignored when trying
       to match the trial completions generated and upper case letters on the
       line match the corresponding lower case letters in the words:

              compadd -M 'L:|[nN][oO]= M:_= M:{[:upper:]}={[:lower:]}' - \
                ${(k)options}

       The first part says that the pattern `[nN][oO]' at the beginning (the
       empty anchor before the pipe symbol) of the string on the line matches
       the empty string in the list of words generated by completion, so it
       will be ignored if present. The second part does the same for an
       underscore anywhere in the command line string, and the third part uses
       correspondence classes so that any upper case letter on the line
       matches the corresponding lower case letter in the word. The use of the
       upper case forms of the specification characters (L and M) guarantees
       that what has already been typed on the command line (in particular the
       prefix no) will not be deleted.

       Note that the use of L in the first part means that it matches only
       when at the beginning of both the command line string and the trial
       completion. I.e., the string `_NO_f' would not be completed to
       `_NO_foo', nor would `NONO_f' be completed to `NONO_foo' because of the
       leading underscore or the second `NO' on the line which makes the
       pattern fail even though they are otherwise ignored. To fix this, one
       would use `B:[nN][oO]=' instead of the first part. As described above,
       this matches at the beginning of the trial completion, independent of
       other characters or substrings at the beginning of the command line
       word which are ignored by the same or other match-specs.

       The second example makes completion case insensitive.  This is just the
       same as in the option example, except here we wish to retain the
       characters in the list of completions:

              compadd -M 'm:{[:lower:]}={[:upper:]}' ...

       This makes lower case letters match their upper case counterparts.  To
       make upper case letters match the lower case forms as well:

              compadd -M 'm:{[:lower:][:upper:]}={[:upper:][:lower:]}' ...

       A nice example for the use of * patterns is partial word completion.
       Sometimes you would like to make strings like `c.s.u' complete to
       strings like `comp.source.unix', i.e. the word on the command line
       consists of multiple parts, separated by a dot in this example, where
       each part should be completed separately -- note, however, that the
       case where each part of the word, i.e. `comp', `source' and `unix' in
       this example, is to be completed from separate sets of matches is a
       different problem to be solved by the implementation of the completion
       widget.  The example can be handled by:

              compadd -M 'r:|.=* r:|=*' \
                - comp.sources.unix comp.sources.misc ...

       The first specification says that lpat is the empty string, while
       anchor is a dot; tpat is *, so this can match anything except for the
       `.' from the anchor in the trial completion word.  So in `c.s.u', the
       matcher sees `c', followed by the empty string, followed by the anchor
       `.', and likewise for the second dot, and replaces the empty strings
       before the anchors, giving `c[omp].s[ources].u[nix]', where the last
       part of the completion is just as normal.

       With the pattern shown above, the string `c.u' could not be completed
       to `comp.sources.unix' because the single star means that no dot
       (matched by the anchor) can be skipped. By using two stars as in
       `r:|.=**', however, `c.u' could be completed to `comp.sources.unix'.
       This also shows that in some cases, especially if the anchor is a real
       pattern, like a character class, the form with two stars may result in
       more matches than one would like.

       The second specification is needed to make this work when the cursor is
       in the middle of the string on the command line and the option
       COMPLETE_IN_WORD is set. In this case the completion code would
       normally try to match trial completions that end with the string as
       typed so far, i.e. it will only insert new characters at the cursor
       position rather than at the end.  However in our example we would like
       the code to recognise matches which contain extra characters after the
       string on the line (the `nix' in the example).  Hence we say that the
       empty string at the end of the string on the line matches any
       characters at the end of the trial completion.

       More generally, the specification

              compadd -M 'r:|[.,_-]=* r:|=*' ...

       allows one to complete words with abbreviations before any of the
       characters in the square brackets.  For example, to complete
       veryverylongfile.c rather than veryverylongheader.h with the above in
       effect, you can just type very.c before attempting completion.

       The specifications with both a left and a right anchor are useful to
       complete partial words whose parts are not separated by some special
       character. For example, in some places strings have to be completed
       that are formed `LikeThis' (i.e. the separate parts are determined by a
       leading upper case letter) or maybe one has to complete strings with
       trailing numbers. Here one could use the simple form with only one
       anchor as in:

              compadd -M 'r:|[[:upper:]0-9]=* r:|=*' LikeTHIS FooHoo 5foo123 5bar234

       But with this, the string `H' would neither complete to `FooHoo' nor to
       `LikeTHIS' because in each case there is an upper case letter before
       the `H' and that is matched by the anchor. Likewise, a `2' would not be
       completed. In both cases this could be changed by using
       `r:|[[:upper:]0-9]=**', but then `H' completes to both `LikeTHIS' and
       `FooHoo' and a `2' matches the other strings because characters can be
       inserted before every upper case letter and digit. To avoid this one
       would use:

              compadd -M 'r:[^[:upper:]0-9]||[[:upper:]0-9]=** r:|=*' \
                  LikeTHIS FooHoo foo123 bar234

       By using these two anchors, a `H' matches only upper case `H's that are
       immediately preceded by something matching the left anchor
       `[^[:upper:]0-9]'. The effect is, of course, that `H' matches only the
       string `FooHoo', a `2' matches only `bar234' and so on.

       When using the completion system (see zshcompsys(1)), users can define
       match specifications that are to be used for specific contexts by using
       the matcher and matcher-list styles. The values for the latter will be
       used everywhere.

COMPLETION WIDGET EXAMPLE
       The first step is to define the widget:

              zle -C complete complete-word complete-files

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

              bindkey '^X\t' complete

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

              complete-files () { compadd - * }

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



zsh 5.8                        February 14, 2020                 ZSHCOMPWID(1)