ZSHCOMPWID(1) ZSHCOMPWID(1)
NAME
zshcompwid - zsh completion widgets
DESCRIPTION
The shell's programmable completion mechanism can be manipulated in two ways; here the low-level fea-tures features
tures 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 cur-rent current
rent 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 func-tion function
tion 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.
SPECIAL PARAMETERS
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 val-ues values
ues 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 con-tains contains
tains 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 char-acter. character.
acter. 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
${.
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 argu-ment argument
ment 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 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 dis-played. displayed.
played. 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 sub-string substring
string 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 com-pletion completion
pletion 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 comple-tion completion
tion 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 when-ever whenever
ever 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 set-tings, settings,
tings, 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 unam-biguous unambiguous
biguous 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.
BUILTIN COMMANDS
compadd [ -akqQfenUld12C ] [ -F array ]
[ -P prefix ] [ -S suffix ]
[ -p hidden-prefix ] [ -s hidden-suffix ]
[ -i ignored-prefix ] [ -I ignored-suffix ]
[ -W file-prefix ] [ -d array ]
[ -J name ] [ -V name ] [ -X explanation ] [ -x message ]
[ -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 com-padd compadd
padd 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 con-tain contain
tain 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 This option only has an effect if used together with the -d option. If it is 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).
-J name
Gives the name of the group of matches the words should be stored in.
-V name
Like -J but naming a unsorted group. These are in a different name space than groups
created with the -J flag.
-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 cur-rently currently
rently selected.
-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 lowercase 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 comple-tion completion
tion 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 mod-ify modify
ify 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 com-pletion completion
pletion 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 `Matching Con-trol'. Control'.
trol'. 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 them-selves. themselves.
selves.
-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
n'th word does not match, the n'th 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 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 use-ful useful
ful 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).
--- given).--
-- 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 contents of the PREFIX parameter is longer than number characters, 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, any-thing anything
thing up to the number'th match is moved. If the number is negative, the number'th
longest match is moved. For example, if PREFIX contains the string `a=b=c', then
compset -P '*\=' will move the string `a=b=' into the IPREFIX parameter, but compset -P
1 '*\=' will move only the string `a='.
-s number
As -p, but transfer the last number characters from the value of SUFFIX to the front of
the value of ISUFFIX.
-S [ number ] pattern
As -P, but match the last portion of SUFFIX and transfer the matched portion to the
front of the value of ISUFFIX.
-n begin [ end ]
If the current word position as specified by the parameter CURRENT is greater than or
equal to begin, anything up to the begin'th word is removed from the words array and
the value of the parameter CURRENT is decremented by begin.
If the optional end is given, the modification is done only if the current word posi-tion position
tion 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 func-tion function
tion (complete-word, etc.) had been called, except that only compctls given for specific com-mands commands
mands 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.
CONDITION CODES
The following additional condition codes for use within the [[ ... ]] construct are available in com-pletion completion
pletion 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.
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 `Builtin Commands' above) consists of one
or more matching descriptions separated by whitespace. Each description consists of a letter fol-lowed followed
lowed 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 uppercase initial
character retains the string already typed on the command line as the final result of completion,
while with a lowercase initial character the string on the command line is changed into the corre-sponding corresponding
sponding 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 lan-chor lanchor
chor 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 trial completion or the word on the command line, 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 trial completion or command line string.
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 delim-ited delimited
ited by a pair of braces, and negated classes are not allowed, so the characters ! and ^ have no spe-cial special
cial 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 lowercase letter on
the line match the corresponding uppercase letter in the trial completion, you can use
`m:{a-z}={A-Z}'. 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 pattern tpat may also be one or two stars, `*' or `**'. This means that the pattern on the com-mand command
mand 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-low-ercase all-lowercase
ercase form, without underscores, and without the optional no at the beginning even though the
builtins setopt and unsetopt understand option names with uppercase 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 uppercase letters on the line match
the corresponding lowercase letters in the words:
compadd -M 'L:|[nN][oO]= M:_= M:{A-Z}={a-z}' - \
${(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 comple-tion, completion,
tion, 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 uppercase letter
on the line matches the corresponding lowercase letter in the word. The use of the uppercase 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 exam-ple, example,
ple, except here we wish to retain the characters in the list of completions:
compadd -M 'm:{a-z}={A-Z}' ...
This makes lowercase letters match their uppercase counterparts. To make uppercase letters match the
lowercase forms as well:
compadd -M 'm:{a-zA-Z}={A-Za-z}' ...
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 then 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 uppercase
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:|[A-Z0-9]=* 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 uppercase 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:|[A-Z0-9]=**', but then `H'
completes to both `LikeTHIS' and `FooHoo' and a `2' matches the other strings because characters can
be inserted before every uppercase letter and digit. To avoid this one would use:
compadd -M 'r:[^A-Z0-9]||[A-Z0-9]=** r:|=*' \
LikeTHIS FooHoo foo123 bar234
By using these two anchors, a `H' matches only uppercase `H's that are immediately preceded by some-thing something
thing matching the left anchor `[^A-Z0-9]'. 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 4.3.4 April 19, 2006 ZSHCOMPWID(1)
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