xref: /vim-8.2.3635/runtime/doc/pattern.txt (revision fc65cabb)
1*pattern.txt*   For Vim version 8.1.  Last change: 2018 Mar 13
2
3
4		  VIM REFERENCE MANUAL    by Bram Moolenaar
5
6
7Patterns and search commands				*pattern-searches*
8
9The very basics can be found in section |03.9| of the user manual.  A few more
10explanations are in chapter 27 |usr_27.txt|.
11
121. Search commands		|search-commands|
132. The definition of a pattern	|search-pattern|
143. Magic			|/magic|
154. Overview of pattern items	|pattern-overview|
165. Multi items			|pattern-multi-items|
176. Ordinary atoms		|pattern-atoms|
187. Ignoring case in a pattern	|/ignorecase|
198. Composing characters		|patterns-composing|
209. Compare with Perl patterns	|perl-patterns|
2110. Highlighting matches	|match-highlight|
22
23==============================================================================
241. Search commands				*search-commands*
25
26							*/*
27/{pattern}[/]<CR>	Search forward for the [count]'th occurrence of
28			{pattern} |exclusive|.
29
30/{pattern}/{offset}<CR>	Search forward for the [count]'th occurrence of
31			{pattern} and go |{offset}| lines up or down.
32			|linewise|.
33
34							*/<CR>*
35/<CR>			Search forward for the [count]'th occurrence of the
36			latest used pattern |last-pattern| with latest used
37			|{offset}|.
38
39//{offset}<CR>		Search forward for the [count]'th occurrence of the
40			latest used pattern |last-pattern| with new
41			|{offset}|.  If {offset} is empty no offset is used.
42
43							*?*
44?{pattern}[?]<CR>	Search backward for the [count]'th previous
45			occurrence of {pattern} |exclusive|.
46
47?{pattern}?{offset}<CR>	Search backward for the [count]'th previous
48			occurrence of {pattern} and go |{offset}| lines up or
49			down |linewise|.
50
51							*?<CR>*
52?<CR>			Search backward for the [count]'th occurrence of the
53			latest used pattern |last-pattern| with latest used
54			|{offset}|.
55
56??{offset}<CR>		Search backward for the [count]'th occurrence of the
57			latest used pattern |last-pattern| with new
58			|{offset}|.  If {offset} is empty no offset is used.
59
60							*n*
61n			Repeat the latest "/" or "?" [count] times.
62			If the cursor doesn't move the search is repeated with
63			count + 1.
64			|last-pattern| {Vi: no count}
65
66							*N*
67N			Repeat the latest "/" or "?" [count] times in
68			opposite direction. |last-pattern| {Vi: no count}
69
70							*star* *E348* *E349*
71*			Search forward for the [count]'th occurrence of the
72			word nearest to the cursor.  The word used for the
73			search is the first of:
74				1. the keyword under the cursor |'iskeyword'|
75				2. the first keyword after the cursor, in the
76				   current line
77				3. the non-blank word under the cursor
78				4. the first non-blank word after the cursor,
79				   in the current line
80			Only whole keywords are searched for, like with the
81			command "/\<keyword\>".  |exclusive|  {not in Vi}
82			'ignorecase' is used, 'smartcase' is not.
83
84							*#*
85#			Same as "*", but search backward.  The pound sign
86			(character 163) also works.  If the "#" key works as
87			backspace, try using "stty erase <BS>" before starting
88			Vim (<BS> is CTRL-H or a real backspace).  {not in Vi}
89
90							*gstar*
91g*			Like "*", but don't put "\<" and "\>" around the word.
92			This makes the search also find matches that are not a
93			whole word.  {not in Vi}
94
95							*g#*
96g#			Like "#", but don't put "\<" and "\>" around the word.
97			This makes the search also find matches that are not a
98			whole word.  {not in Vi}
99
100							*gd*
101gd			Goto local Declaration.  When the cursor is on a local
102			variable, this command will jump to its declaration.
103			First Vim searches for the start of the current
104			function, just like "[[".  If it is not found the
105			search stops in line 1.  If it is found, Vim goes back
106			until a blank line is found.  From this position Vim
107			searches for the keyword under the cursor, like with
108			"*", but lines that look like a comment are ignored
109			(see 'comments' option).
110			Note that this is not guaranteed to work, Vim does not
111			really check the syntax, it only searches for a match
112			with the keyword.  If included files also need to be
113			searched use the commands listed in |include-search|.
114			After this command |n| searches forward for the next
115			match (not backward).
116			{not in Vi}
117
118							*gD*
119gD			Goto global Declaration.  When the cursor is on a
120			global variable that is defined in the file, this
121			command will jump to its declaration.  This works just
122			like "gd", except that the search for the keyword
123			always starts in line 1.  {not in Vi}
124
125							*1gd*
1261gd			Like "gd", but ignore matches inside a {} block that
127			ends before the cursor position. {not in Vi}
128
129							*1gD*
1301gD			Like "gD", but ignore matches inside a {} block that
131			ends before the cursor position. {not in Vi}
132
133							*CTRL-C*
134CTRL-C			Interrupt current (search) command.  Use CTRL-Break on
135			MS-DOS |dos-CTRL-Break|.
136			In Normal mode, any pending command is aborted.
137
138							*:noh* *:nohlsearch*
139:noh[lsearch]		Stop the highlighting for the 'hlsearch' option.  It
140			is automatically turned back on when using a search
141			command, or setting the 'hlsearch' option.
142			This command doesn't work in an autocommand, because
143			the highlighting state is saved and restored when
144			executing autocommands |autocmd-searchpat|.
145			Same thing for when invoking a user function.
146
147While typing the search pattern the current match will be shown if the
148'incsearch' option is on.  Remember that you still have to finish the search
149command with <CR> to actually position the cursor at the displayed match.  Or
150use <Esc> to abandon the search.
151
152All matches for the last used search pattern will be highlighted if you set
153the 'hlsearch' option.  This can be suspended with the |:nohlsearch| command.
154
155When no match is found you get the error: *E486* Pattern not found
156Note that for the |:global| command this behaves like a normal message, for Vi
157compatibility.  For the |:s| command the "e" flag can be used to avoid the
158error message |:s_flags|.
159
160					*search-offset* *{offset}*
161These commands search for the specified pattern.  With "/" and "?" an
162additional offset may be given.  There are two types of offsets: line offsets
163and character offsets.  {the character offsets are not in Vi}
164
165The offset gives the cursor position relative to the found match:
166    [num]	[num] lines downwards, in column 1
167    +[num]	[num] lines downwards, in column 1
168    -[num]	[num] lines upwards, in column 1
169    e[+num]	[num] characters to the right of the end of the match
170    e[-num]	[num] characters to the left of the end of the match
171    s[+num]	[num] characters to the right of the start of the match
172    s[-num]	[num] characters to the left of the start of the match
173    b[+num]	[num] identical to s[+num] above (mnemonic: begin)
174    b[-num]	[num] identical to s[-num] above (mnemonic: begin)
175    ;{pattern}  perform another search, see |//;|
176
177If a '-' or '+' is given but [num] is omitted, a count of one will be used.
178When including an offset with 'e', the search becomes inclusive (the
179character the cursor lands on is included in operations).
180
181Examples:
182
183pattern			cursor position	~
184/test/+1		one line below "test", in column 1
185/test/e			on the last t of "test"
186/test/s+2		on the 's' of "test"
187/test/b-3		three characters before "test"
188
189If one of these commands is used after an operator, the characters between
190the cursor position before and after the search is affected.  However, if a
191line offset is given, the whole lines between the two cursor positions are
192affected.
193
194An example of how to search for matches with a pattern and change the match
195with another word: >
196	/foo<CR>	find "foo"
197	c//e<CR>	change until end of match
198	bar<Esc>	type replacement
199	//<CR>		go to start of next match
200	c//e<CR>	change until end of match
201	beep<Esc>	type another replacement
202			etc.
203<
204							*//;* *E386*
205A very special offset is ';' followed by another search command.  For example: >
206
207   /test 1/;/test
208   /test.*/+1;?ing?
209
210The first one first finds the next occurrence of "test 1", and then the first
211occurrence of "test" after that.
212
213This is like executing two search commands after each other, except that:
214- It can be used as a single motion command after an operator.
215- The direction for a following "n" or "N" command comes from the first
216  search command.
217- When an error occurs the cursor is not moved at all.
218
219							*last-pattern*
220The last used pattern and offset are remembered.  They can be used to repeat
221the search, possibly in another direction or with another count.  Note that
222two patterns are remembered: One for 'normal' search commands and one for the
223substitute command ":s".  Each time an empty pattern is given, the previously
224used pattern is used.  However, if there is no previous search command, a
225previous substitute pattern is used, if possible.
226
227The 'magic' option sticks with the last used pattern.  If you change 'magic',
228this will not change how the last used pattern will be interpreted.
229The 'ignorecase' option does not do this.  When 'ignorecase' is changed, it
230will result in the pattern to match other text.
231
232All matches for the last used search pattern will be highlighted if you set
233the 'hlsearch' option.
234
235To clear the last used search pattern: >
236	:let @/ = ""
237This will not set the pattern to an empty string, because that would match
238everywhere.  The pattern is really cleared, like when starting Vim.
239
240The search usually skips matches that don't move the cursor.  Whether the next
241match is found at the next character or after the skipped match depends on the
242'c' flag in 'cpoptions'.  See |cpo-c|.
243	   with 'c' flag:   "/..." advances 1 to 3 characters
244	without 'c' flag:   "/..." advances 1 character
245The unpredictability with the 'c' flag is caused by starting the search in the
246first column, skipping matches until one is found past the cursor position.
247
248When searching backwards, searching starts at the start of the line, using the
249'c' flag in 'cpoptions' as described above.  Then the last match before the
250cursor position is used.
251
252In Vi the ":tag" command sets the last search pattern when the tag is searched
253for.  In Vim this is not done, the previous search pattern is still remembered,
254unless the 't' flag is present in 'cpoptions'.  The search pattern is always
255put in the search history.
256
257If the 'wrapscan' option is on (which is the default), searches wrap around
258the end of the buffer.  If 'wrapscan' is not set, the backward search stops
259at the beginning and the forward search stops at the end of the buffer.  If
260'wrapscan' is set and the pattern was not found the error message "pattern
261not found" is given, and the cursor will not be moved.  If 'wrapscan' is not
262set the message becomes "search hit BOTTOM without match" when searching
263forward, or "search hit TOP without match" when searching backward.  If
264wrapscan is set and the search wraps around the end of the file the message
265"search hit TOP, continuing at BOTTOM" or "search hit BOTTOM, continuing at
266TOP" is given when searching backwards or forwards respectively.  This can be
267switched off by setting the 's' flag in the 'shortmess' option.  The highlight
268method 'w' is used for this message (default: standout).
269
270							*search-range*
271You can limit the search command "/" to a certain range of lines by including
272\%>l items.  For example, to match the word "limit" below line 199 and above
273line 300: >
274	/\%>199l\%<300llimit
275Also see |/\%>l|.
276
277Another way is to use the ":substitute" command with the 'c' flag.  Example: >
278   :.,300s/Pattern//gc
279This command will search from the cursor position until line 300 for
280"Pattern".  At the match, you will be asked to type a character.  Type 'q' to
281stop at this match, type 'n' to find the next match.
282
283The "*", "#", "g*" and "g#" commands look for a word near the cursor in this
284order, the first one that is found is used:
285- The keyword currently under the cursor.
286- The first keyword to the right of the cursor, in the same line.
287- The WORD currently under the cursor.
288- The first WORD to the right of the cursor, in the same line.
289The keyword may only contain letters and characters in 'iskeyword'.
290The WORD may contain any non-blanks (<Tab>s and/or <Space>s).
291Note that if you type with ten fingers, the characters are easy to remember:
292the "#" is under your left hand middle finger (search to the left and up) and
293the "*" is under your right hand middle finger (search to the right and down).
294(this depends on your keyboard layout though).
295
296								*E956*
297In very rare cases a regular expression is used recursively.  This can happen
298when executing a pattern takes a long time and when checkig for messages on
299channels a callback is invoked that also uses a pattern or an autocommand is
300triggered.  In most cases this should be fine, but if a pattern is in use when
301it's used again it fails.  Usually this means there is something wrong with
302the pattern.
303
304==============================================================================
3052. The definition of a pattern		*search-pattern* *pattern* *[pattern]*
306					*regular-expression* *regexp* *Pattern*
307					*E76* *E383* *E476*
308
309For starters, read chapter 27 of the user manual |usr_27.txt|.
310
311						*/bar* */\bar* */pattern*
3121. A pattern is one or more branches, separated by "\|".  It matches anything
313   that matches one of the branches.  Example: "foo\|beep" matches "foo" and
314   matches "beep".  If more than one branch matches, the first one is used.
315
316   pattern ::=	    branch
317		or  branch \| branch
318		or  branch \| branch \| branch
319		etc.
320
321						*/branch* */\&*
3222. A branch is one or more concats, separated by "\&".  It matches the last
323   concat, but only if all the preceding concats also match at the same
324   position.  Examples:
325	"foobeep\&..." matches "foo" in "foobeep".
326	".*Peter\&.*Bob" matches in a line containing both "Peter" and "Bob"
327
328   branch ::=	    concat
329		or  concat \& concat
330		or  concat \& concat \& concat
331		etc.
332
333						*/concat*
3343. A concat is one or more pieces, concatenated.  It matches a match for the
335   first piece, followed by a match for the second piece, etc.  Example:
336   "f[0-9]b", first matches "f", then a digit and then "b".
337
338   concat  ::=	    piece
339		or  piece piece
340		or  piece piece piece
341		etc.
342
343						*/piece*
3444. A piece is an atom, possibly followed by a multi, an indication of how many
345   times the atom can be matched.  Example: "a*" matches any sequence of "a"
346   characters: "", "a", "aa", etc.  See |/multi|.
347
348   piece   ::=	    atom
349		or  atom  multi
350
351						*/atom*
3525. An atom can be one of a long list of items.  Many atoms match one character
353   in the text.  It is often an ordinary character or a character class.
354   Braces can be used to make a pattern into an atom.  The "\z(\)" construct
355   is only for syntax highlighting.
356
357   atom    ::=	    ordinary-atom		|/ordinary-atom|
358		or  \( pattern \)		|/\(|
359		or  \%( pattern \)		|/\%(|
360		or  \z( pattern \)		|/\z(|
361
362
363				*/\%#=* *two-engines* *NFA*
364Vim includes two regexp engines:
3651. An old, backtracking engine that supports everything.
3662. A new, NFA engine that works much faster on some patterns, possibly slower
367   on some patterns.
368
369Vim will automatically select the right engine for you.  However, if you run
370into a problem or want to specifically select one engine or the other, you can
371prepend one of the following to the pattern:
372
373	\%#=0	Force automatic selection.  Only has an effect when
374	        'regexpengine' has been set to a non-zero value.
375	\%#=1	Force using the old engine.
376	\%#=2	Force using the NFA engine.
377
378You can also use the 'regexpengine' option to change the default.
379
380			 *E864* *E868* *E874* *E875* *E876* *E877* *E878*
381If selecting the NFA engine and it runs into something that is not implemented
382the pattern will not match.  This is only useful when debugging Vim.
383
384==============================================================================
3853. Magic							*/magic*
386
387Some characters in the pattern are taken literally.  They match with the same
388character in the text.  When preceded with a backslash however, these
389characters get a special meaning.
390
391Other characters have a special meaning without a backslash.  They need to be
392preceded with a backslash to match literally.
393
394If a character is taken literally or not depends on the 'magic' option and the
395items mentioned next.
396							*/\m* */\M*
397Use of "\m" makes the pattern after it be interpreted as if 'magic' is set,
398ignoring the actual value of the 'magic' option.
399Use of "\M" makes the pattern after it be interpreted as if 'nomagic' is used.
400							*/\v* */\V*
401Use of "\v" means that in the pattern after it all ASCII characters except
402'0'-'9', 'a'-'z', 'A'-'Z' and '_' have a special meaning.  "very magic"
403
404Use of "\V" means that in the pattern after it only the backslash and the
405terminating character (/ or ?) has a special meaning.  "very nomagic"
406
407Examples:
408after:	  \v	   \m	    \M	     \V		matches ~
409		'magic' 'nomagic'
410	  $	   $	    $	     \$		matches end-of-line
411	  .	   .	    \.	     \.		matches any character
412	  *	   *	    \*	     \*		any number of the previous atom
413	  ~	   ~	    \~	     \~		latest substitute string
414	  ()	   \(\)     \(\)     \(\)	grouping into an atom
415	  |	   \|	    \|	     \|		separating alternatives
416	  \a	   \a	    \a	     \a		alphabetic character
417	  \\	   \\	    \\	     \\		literal backslash
418	  \.	   \.	    .	     .		literal dot
419	  \{	   {	    {	     {		literal '{'
420	  a	   a	    a	     a		literal 'a'
421
422{only Vim supports \m, \M, \v and \V}
423
424It is recommended to always keep the 'magic' option at the default setting,
425which is 'magic'.  This avoids portability problems.  To make a pattern immune
426to the 'magic' option being set or not, put "\m" or "\M" at the start of the
427pattern.
428
429==============================================================================
4304. Overview of pattern items				*pattern-overview*
431						*E865* *E866* *E867* *E869*
432
433Overview of multi items.				*/multi* *E61* *E62*
434More explanation and examples below, follow the links.		*E64* *E871*
435
436	  multi ~
437     'magic' 'nomagic'	matches of the preceding atom ~
438|/star|	*	\*	0 or more	as many as possible
439|/\+|	\+	\+	1 or more	as many as possible (*)
440|/\=|	\=	\=	0 or 1		as many as possible (*)
441|/\?|	\?	\?	0 or 1		as many as possible (*)
442
443|/\{|	\{n,m}	\{n,m}	n to m		as many as possible (*)
444	\{n}	\{n}	n		exactly (*)
445	\{n,}	\{n,}	at least n	as many as possible (*)
446	\{,m}	\{,m}	0 to m		as many as possible (*)
447	\{}	\{}	0 or more	as many as possible (same as *) (*)
448
449|/\{-|	\{-n,m}	\{-n,m}	n to m		as few as possible (*)
450	\{-n}	\{-n}	n		exactly (*)
451	\{-n,}	\{-n,}	at least n	as few as possible (*)
452	\{-,m}	\{-,m}	0 to m		as few as possible (*)
453	\{-}	\{-}	0 or more	as few as possible (*)
454
455							*E59*
456|/\@>|	\@>	\@>	1, like matching a whole pattern (*)
457|/\@=|	\@=	\@=	nothing, requires a match |/zero-width| (*)
458|/\@!|	\@!	\@!	nothing, requires NO match |/zero-width| (*)
459|/\@<=|	\@<=	\@<=	nothing, requires a match behind |/zero-width| (*)
460|/\@<!|	\@<!	\@<!	nothing, requires NO match behind |/zero-width| (*)
461
462(*) {not in Vi}
463
464
465Overview of ordinary atoms.				*/ordinary-atom*
466More explanation and examples below, follow the links.
467
468      ordinary atom ~
469      magic   nomagic	matches ~
470|/^|	^	^	start-of-line (at start of pattern) |/zero-width|
471|/\^|	\^	\^	literal '^'
472|/\_^|	\_^	\_^	start-of-line (used anywhere) |/zero-width|
473|/$|	$	$	end-of-line (at end of pattern) |/zero-width|
474|/\$|	\$	\$	literal '$'
475|/\_$|	\_$	\_$	end-of-line (used anywhere) |/zero-width|
476|/.|	.	\.	any single character (not an end-of-line)
477|/\_.|	\_.	\_.	any single character or end-of-line
478|/\<|	\<	\<	beginning of a word |/zero-width|
479|/\>|	\>	\>	end of a word |/zero-width|
480|/\zs|	\zs	\zs	anything, sets start of match
481|/\ze|	\ze	\ze	anything, sets end of match
482|/\%^|	\%^	\%^	beginning of file |/zero-width|		*E71*
483|/\%$|	\%$	\%$	end of file |/zero-width|
484|/\%V|	\%V	\%V	inside Visual area |/zero-width|
485|/\%#|	\%#	\%#	cursor position |/zero-width|
486|/\%'m|	\%'m	\%'m	mark m position |/zero-width|
487|/\%l|	\%23l	\%23l	in line 23 |/zero-width|
488|/\%c|	\%23c	\%23c	in column 23 |/zero-width|
489|/\%v|	\%23v	\%23v	in virtual column 23 |/zero-width|
490
491Character classes {not in Vi}:				*/character-classes*
492      magic   nomagic	matches ~
493|/\i|	\i	\i	identifier character (see 'isident' option)
494|/\I|	\I	\I	like "\i", but excluding digits
495|/\k|	\k	\k	keyword character (see 'iskeyword' option)
496|/\K|	\K	\K	like "\k", but excluding digits
497|/\f|	\f	\f	file name character (see 'isfname' option)
498|/\F|	\F	\F	like "\f", but excluding digits
499|/\p|	\p	\p	printable character (see 'isprint' option)
500|/\P|	\P	\P	like "\p", but excluding digits
501|/\s|	\s	\s	whitespace character: <Space> and <Tab>
502|/\S|	\S	\S	non-whitespace character; opposite of \s
503|/\d|	\d	\d	digit:				[0-9]
504|/\D|	\D	\D	non-digit:			[^0-9]
505|/\x|	\x	\x	hex digit:			[0-9A-Fa-f]
506|/\X|	\X	\X	non-hex digit:			[^0-9A-Fa-f]
507|/\o|	\o	\o	octal digit:			[0-7]
508|/\O|	\O	\O	non-octal digit:		[^0-7]
509|/\w|	\w	\w	word character:			[0-9A-Za-z_]
510|/\W|	\W	\W	non-word character:		[^0-9A-Za-z_]
511|/\h|	\h	\h	head of word character:		[A-Za-z_]
512|/\H|	\H	\H	non-head of word character:	[^A-Za-z_]
513|/\a|	\a	\a	alphabetic character:		[A-Za-z]
514|/\A|	\A	\A	non-alphabetic character:	[^A-Za-z]
515|/\l|	\l	\l	lowercase character:		[a-z]
516|/\L|	\L	\L	non-lowercase character:	[^a-z]
517|/\u|	\u	\u	uppercase character:		[A-Z]
518|/\U|	\U	\U	non-uppercase character		[^A-Z]
519|/\_|	\_x	\_x	where x is any of the characters above: character
520			class with end-of-line included
521(end of character classes)
522
523      magic   nomagic	matches ~
524|/\e|	\e	\e	<Esc>
525|/\t|	\t	\t	<Tab>
526|/\r|	\r	\r	<CR>
527|/\b|	\b	\b	<BS>
528|/\n|	\n	\n	end-of-line
529|/~|	~	\~	last given substitute string
530|/\1|	\1	\1	same string as matched by first \(\) {not in Vi}
531|/\2|	\2	\2	Like "\1", but uses second \(\)
532	   ...
533|/\9|	\9	\9	Like "\1", but uses ninth \(\)
534								*E68*
535|/\z1|	\z1	\z1	only for syntax highlighting, see |:syn-ext-match|
536	   ...
537|/\z1|	\z9	\z9	only for syntax highlighting, see |:syn-ext-match|
538
539	x	x	a character with no special meaning matches itself
540
541|/[]|	[]	\[]	any character specified inside the []
542|/\%[]|	\%[]	\%[]	a sequence of optionally matched atoms
543
544|/\c|	\c	\c	ignore case, do not use the 'ignorecase' option
545|/\C|	\C	\C	match case, do not use the 'ignorecase' option
546|/\Z|	\Z	\Z	ignore differences in Unicode "combining characters".
547			Useful when searching voweled Hebrew or Arabic text.
548
549      magic   nomagic	matches ~
550|/\m|	\m	\m	'magic' on for the following chars in the pattern
551|/\M|	\M	\M	'magic' off for the following chars in the pattern
552|/\v|	\v	\v	the following chars in the pattern are "very magic"
553|/\V|	\V	\V	the following chars in the pattern are "very nomagic"
554|/\%#=|   \%#=1   \%#=1   select regexp engine |/zero-width|
555
556|/\%d|	\%d	\%d	match specified decimal character (eg \%d123)
557|/\%x|	\%x	\%x	match specified hex character (eg \%x2a)
558|/\%o|	\%o	\%o	match specified octal character (eg \%o040)
559|/\%u|	\%u	\%u	match specified multibyte character (eg \%u20ac)
560|/\%U|	\%U	\%U	match specified large multibyte character (eg
561			\%U12345678)
562|/\%C|	\%C	\%C	match any composing characters
563
564Example			matches ~
565\<\I\i*		or
566\<\h\w*
567\<[a-zA-Z_][a-zA-Z0-9_]*
568			An identifier (e.g., in a C program).
569
570\(\.$\|\. \)		A period followed by <EOL> or a space.
571
572[.!?][])"']*\($\|[ ]\)	A search pattern that finds the end of a sentence,
573			with almost the same definition as the ")" command.
574
575cat\Z			Both "cat" and "càt" ("a" followed by 0x0300)
576			Does not match "càt" (character 0x00e0), even
577			though it may look the same.
578
579
580==============================================================================
5815. Multi items						*pattern-multi-items*
582
583An atom can be followed by an indication of how many times the atom can be
584matched and in what way.  This is called a multi.  See |/multi| for an
585overview.
586
587							*/star* */\star*
588*	(use \* when 'magic' is not set)
589	Matches 0 or more of the preceding atom, as many as possible.
590	Example  'nomagic'	matches ~
591	a*	   a\*		"", "a", "aa", "aaa", etc.
592	.*	   \.\*		anything, also an empty string, no end-of-line
593	\_.*	   \_.\*	everything up to the end of the buffer
594	\_.*END	   \_.\*END	everything up to and including the last "END"
595				in the buffer
596
597	Exception: When "*" is used at the start of the pattern or just after
598	"^" it matches the star character.
599
600	Be aware that repeating "\_." can match a lot of text and take a long
601	time.  For example, "\_.*END" matches all text from the current
602	position to the last occurrence of "END" in the file.  Since the "*"
603	will match as many as possible, this first skips over all lines until
604	the end of the file and then tries matching "END", backing up one
605	character at a time.
606
607							*/\+*
608\+	Matches 1 or more of the preceding atom, as many as possible. {not in
609	Vi}
610	Example		matches ~
611	^.\+$		any non-empty line
612	\s\+		white space of at least one character
613
614							*/\=*
615\=	Matches 0 or 1 of the preceding atom, as many as possible. {not in Vi}
616	Example		matches ~
617	foo\=		"fo" and "foo"
618
619							*/\?*
620\?	Just like \=.  Cannot be used when searching backwards with the "?"
621	command. {not in Vi}
622
623					*/\{* *E60* *E554* *E870*
624\{n,m}	Matches n to m of the preceding atom, as many as possible
625\{n}	Matches n of the preceding atom
626\{n,}	Matches at least n of the preceding atom, as many as possible
627\{,m}	Matches 0 to m of the preceding atom, as many as possible
628\{}	Matches 0 or more of the preceding atom, as many as possible (like *)
629							*/\{-*
630\{-n,m}	matches n to m of the preceding atom, as few as possible
631\{-n}	matches n of the preceding atom
632\{-n,}	matches at least n of the preceding atom, as few as possible
633\{-,m}	matches 0 to m of the preceding atom, as few as possible
634\{-}	matches 0 or more of the preceding atom, as few as possible
635	{Vi does not have any of these}
636
637	n and m are positive decimal numbers or zero
638								*non-greedy*
639	If a "-" appears immediately after the "{", then a shortest match
640	first algorithm is used (see example below).  In particular, "\{-}" is
641	the same as "*" but uses the shortest match first algorithm.  BUT: A
642	match that starts earlier is preferred over a shorter match: "a\{-}b"
643	matches "aaab" in "xaaab".
644
645	Example			matches ~
646	ab\{2,3}c		"abbc" or "abbbc"
647	a\{5}			"aaaaa"
648	ab\{2,}c		"abbc", "abbbc", "abbbbc", etc.
649	ab\{,3}c		"ac", "abc", "abbc" or "abbbc"
650	a[bc]\{3}d		"abbbd", "abbcd", "acbcd", "acccd", etc.
651	a\(bc\)\{1,2}d		"abcd" or "abcbcd"
652	a[bc]\{-}[cd]		"abc" in "abcd"
653	a[bc]*[cd]		"abcd" in "abcd"
654
655	The } may optionally be preceded with a backslash: \{n,m\}.
656
657							*/\@=*
658\@=	Matches the preceding atom with zero width. {not in Vi}
659	Like "(?=pattern)" in Perl.
660	Example			matches ~
661	foo\(bar\)\@=		"foo" in "foobar"
662	foo\(bar\)\@=foo	nothing
663							*/zero-width*
664	When using "\@=" (or "^", "$", "\<", "\>") no characters are included
665	in the match.  These items are only used to check if a match can be
666	made.  This can be tricky, because a match with following items will
667	be done in the same position.  The last example above will not match
668	"foobarfoo", because it tries match "foo" in the same position where
669	"bar" matched.
670
671	Note that using "\&" works the same as using "\@=": "foo\&.." is the
672	same as "\(foo\)\@=..".  But using "\&" is easier, you don't need the
673	braces.
674
675
676							*/\@!*
677\@!	Matches with zero width if the preceding atom does NOT match at the
678	current position. |/zero-width| {not in Vi}
679	Like "(?!pattern)" in Perl.
680	Example			matches ~
681	foo\(bar\)\@!		any "foo" not followed by "bar"
682	a.\{-}p\@!		"a", "ap", "app", "appp", etc. not immediately
683				followed by a "p"
684	if \(\(then\)\@!.\)*$	"if " not followed by "then"
685
686	Using "\@!" is tricky, because there are many places where a pattern
687	does not match.  "a.*p\@!" will match from an "a" to the end of the
688	line, because ".*" can match all characters in the line and the "p"
689	doesn't match at the end of the line.  "a.\{-}p\@!" will match any
690	"a", "ap", "app", etc. that isn't followed by a "p", because the "."
691	can match a "p" and "p\@!" doesn't match after that.
692
693	You can't use "\@!" to look for a non-match before the matching
694	position: "\(foo\)\@!bar" will match "bar" in "foobar", because at the
695	position where "bar" matches, "foo" does not match.  To avoid matching
696	"foobar" you could use "\(foo\)\@!...bar", but that doesn't match a
697	bar at the start of a line.  Use "\(foo\)\@<!bar".
698
699	Useful example: to find "foo" in a line that does not contain "bar": >
700		/^\%(.*bar\)\@!.*\zsfoo
701<	This pattern first checks that there is not a single position in the
702	line where "bar" matches.  If ".*bar" matches somewhere the \@! will
703	reject the pattern.  When there is no match any "foo" will be found.
704	The "\zs" is to have the match start just before "foo".
705
706							*/\@<=*
707\@<=	Matches with zero width if the preceding atom matches just before what
708	follows. |/zero-width| {not in Vi}
709	Like "(?<=pattern)" in Perl, but Vim allows non-fixed-width patterns.
710	Example			matches ~
711	\(an\_s\+\)\@<=file	"file" after "an" and white space or an
712				end-of-line
713	For speed it's often much better to avoid this multi.  Try using "\zs"
714	instead |/\zs|.  To match the same as the above example:
715		an\_s\+\zsfile
716	At least set a limit for the look-behind, see below.
717
718	"\@<=" and "\@<!" check for matches just before what follows.
719	Theoretically these matches could start anywhere before this position.
720	But to limit the time needed, only the line where what follows matches
721	is searched, and one line before that (if there is one).  This should
722	be sufficient to match most things and not be too slow.
723
724	In the old regexp engine the part of the pattern after "\@<=" and
725	"\@<!" are checked for a match first, thus things like "\1" don't work
726	to reference \(\) inside the preceding atom.  It does work the other
727	way around:
728	Bad example			matches ~
729	\%#=1\1\@<=,\([a-z]\+\)		",abc" in "abc,abc"
730
731	However, the new regexp engine works differently, it is better to not
732	rely on this behavior, do not use \@<= if it can be avoided:
733	Example				matches ~
734	\([a-z]\+\)\zs,\1		",abc" in "abc,abc"
735
736\@123<=
737	Like "\@<=" but only look back 123 bytes. This avoids trying lots
738	of matches that are known to fail and make executing the pattern very
739	slow.  Example, check if there is a "<" just before "span":
740		/<\@1<=span
741	This will try matching "<" only one byte before "span", which is the
742	only place that works anyway.
743	After crossing a line boundary, the limit is relative to the end of
744	the line.  Thus the characters at the start of the line with the match
745	are not counted (this is just to keep it simple).
746	The number zero is the same as no limit.
747
748							*/\@<!*
749\@<!	Matches with zero width if the preceding atom does NOT match just
750	before what follows.  Thus this matches if there is no position in the
751	current or previous line where the atom matches such that it ends just
752	before what follows.  |/zero-width| {not in Vi}
753	Like "(?<!pattern)" in Perl, but Vim allows non-fixed-width patterns.
754	The match with the preceding atom is made to end just before the match
755	with what follows, thus an atom that ends in ".*" will work.
756	Warning: This can be slow (because many positions need to be checked
757	for a match).  Use a limit if you can, see below.
758	Example			matches ~
759	\(foo\)\@<!bar		any "bar" that's not in "foobar"
760	\(\/\/.*\)\@<!in	"in" which is not after "//"
761
762\@123<!
763	Like "\@<!" but only look back 123 bytes. This avoids trying lots of
764	matches that are known to fail and make executing the pattern very
765	slow.
766
767							*/\@>*
768\@>	Matches the preceding atom like matching a whole pattern. {not in Vi}
769	Like "(?>pattern)" in Perl.
770	Example		matches ~
771	\(a*\)\@>a	nothing (the "a*" takes all the "a"'s, there can't be
772			another one following)
773
774	This matches the preceding atom as if it was a pattern by itself.  If
775	it doesn't match, there is no retry with shorter sub-matches or
776	anything.  Observe this difference: "a*b" and "a*ab" both match
777	"aaab", but in the second case the "a*" matches only the first two
778	"a"s.  "\(a*\)\@>ab" will not match "aaab", because the "a*" matches
779	the "aaa" (as many "a"s as possible), thus the "ab" can't match.
780
781
782==============================================================================
7836.  Ordinary atoms					*pattern-atoms*
784
785An ordinary atom can be:
786
787							*/^*
788^	At beginning of pattern or after "\|", "\(", "\%(" or "\n": matches
789	start-of-line; at other positions, matches literal '^'. |/zero-width|
790	Example		matches ~
791	^beep(		the start of the C function "beep" (probably).
792
793							*/\^*
794\^	Matches literal '^'.  Can be used at any position in the pattern.
795
796							*/\_^*
797\_^	Matches start-of-line. |/zero-width|  Can be used at any position in
798	the pattern.
799	Example		matches ~
800	\_s*\_^foo	white space and blank lines and then "foo" at
801			start-of-line
802
803							*/$*
804$	At end of pattern or in front of "\|", "\)" or "\n" ('magic' on):
805	matches end-of-line <EOL>; at other positions, matches literal '$'.
806	|/zero-width|
807
808							*/\$*
809\$	Matches literal '$'.  Can be used at any position in the pattern.
810
811							*/\_$*
812\_$	Matches end-of-line. |/zero-width|  Can be used at any position in the
813	pattern.  Note that "a\_$b" never matches, since "b" cannot match an
814	end-of-line.  Use "a\nb" instead |/\n|.
815	Example		matches ~
816	foo\_$\_s*	"foo" at end-of-line and following white space and
817			blank lines
818
819.	(with 'nomagic': \.)				*/.* */\.*
820	Matches any single character, but not an end-of-line.
821
822							*/\_.*
823\_.	Matches any single character or end-of-line.
824	Careful: "\_.*" matches all text to the end of the buffer!
825
826							*/\<*
827\<	Matches the beginning of a word: The next char is the first char of a
828	word.  The 'iskeyword' option specifies what is a word character.
829	|/zero-width|
830
831							*/\>*
832\>	Matches the end of a word: The previous char is the last char of a
833	word.  The 'iskeyword' option specifies what is a word character.
834	|/zero-width|
835
836							*/\zs*
837\zs	Matches at any position, and sets the start of the match there: The
838	next char is the first char of the whole match. |/zero-width|
839	Example: >
840		/^\s*\zsif
841<	matches an "if" at the start of a line, ignoring white space.
842	Can be used multiple times, the last one encountered in a matching
843	branch is used.  Example: >
844		/\(.\{-}\zsFab\)\{3}
845<	Finds the third occurrence of "Fab".
846	This cannot be followed by a multi. *E888*
847	{not in Vi} {not available when compiled without the |+syntax| feature}
848							*/\ze*
849\ze	Matches at any position, and sets the end of the match there: The
850	previous char is the last char of the whole match. |/zero-width|
851	Can be used multiple times, the last one encountered in a matching
852	branch is used.
853	Example: "end\ze\(if\|for\)" matches the "end" in "endif" and
854	"endfor".
855	This cannot be followed by a multi. |E888|
856	{not in Vi} {not available when compiled without the |+syntax| feature}
857
858						*/\%^* *start-of-file*
859\%^	Matches start of the file.  When matching with a string, matches the
860	start of the string. {not in Vi}
861	For example, to find the first "VIM" in a file: >
862		/\%^\_.\{-}\zsVIM
863<
864						*/\%$* *end-of-file*
865\%$	Matches end of the file.  When matching with a string, matches the
866	end of the string. {not in Vi}
867	Note that this does NOT find the last "VIM" in a file: >
868		/VIM\_.\{-}\%$
869<	It will find the next VIM, because the part after it will always
870	match.  This one will find the last "VIM" in the file: >
871		/VIM\ze\(\(VIM\)\@!\_.\)*\%$
872<	This uses |/\@!| to ascertain that "VIM" does NOT match in any
873	position after the first "VIM".
874	Searching from the end of the file backwards is easier!
875
876						*/\%V*
877\%V	Match inside the Visual area.  When Visual mode has already been
878	stopped match in the area that |gv| would reselect.
879	This is a |/zero-width| match.  To make sure the whole pattern is
880	inside the Visual area put it at the start and just before the end of
881	the pattern, e.g.: >
882		/\%Vfoo.*ba\%Vr
883<	This also works if only "foo bar" was Visually selected. This: >
884		/\%Vfoo.*bar\%V
885<	would match "foo bar" if the Visual selection continues after the "r".
886	Only works for the current buffer.
887
888						*/\%#* *cursor-position*
889\%#	Matches with the cursor position.  Only works when matching in a
890	buffer displayed in a window. {not in Vi}
891	WARNING: When the cursor is moved after the pattern was used, the
892	result becomes invalid.  Vim doesn't automatically update the matches.
893	This is especially relevant for syntax highlighting and 'hlsearch'.
894	In other words: When the cursor moves the display isn't updated for
895	this change.  An update is done for lines which are changed (the whole
896	line is updated) or when using the |CTRL-L| command (the whole screen
897	is updated).  Example, to highlight the word under the cursor: >
898		/\k*\%#\k*
899<	When 'hlsearch' is set and you move the cursor around and make changes
900	this will clearly show when the match is updated or not.
901
902						*/\%'m* */\%<'m* */\%>'m*
903\%'m	Matches with the position of mark m.
904\%<'m	Matches before the position of mark m.
905\%>'m	Matches after the position of mark m.
906	Example, to highlight the text from mark 's to 'e: >
907		/.\%>'s.*\%<'e..
908<	Note that two dots are required to include mark 'e in the match.  That
909	is because "\%<'e" matches at the character before the 'e mark, and
910	since it's a |/zero-width| match it doesn't include that character.
911	{not in Vi}
912	WARNING: When the mark is moved after the pattern was used, the result
913	becomes invalid.  Vim doesn't automatically update the matches.
914	Similar to moving the cursor for "\%#" |/\%#|.
915
916						*/\%l* */\%>l* */\%<l* *E951*
917\%23l	Matches in a specific line.
918\%<23l	Matches above a specific line (lower line number).
919\%>23l	Matches below a specific line (higher line number).
920	These three can be used to match specific lines in a buffer.  The "23"
921	can be any line number.  The first line is 1. {not in Vi}
922	WARNING: When inserting or deleting lines Vim does not automatically
923	update the matches.  This means Syntax highlighting quickly becomes
924	wrong.
925	Example, to highlight the line where the cursor currently is: >
926		:exe '/\%' . line(".") . 'l.*'
927<	When 'hlsearch' is set and you move the cursor around and make changes
928	this will clearly show when the match is updated or not.
929
930						*/\%c* */\%>c* */\%<c*
931\%23c	Matches in a specific column.
932\%<23c	Matches before a specific column.
933\%>23c	Matches after a specific column.
934	These three can be used to match specific columns in a buffer or
935	string.  The "23" can be any column number.  The first column is 1.
936	Actually, the column is the byte number (thus it's not exactly right
937	for multi-byte characters).  {not in Vi}
938	WARNING: When inserting or deleting text Vim does not automatically
939	update the matches.  This means Syntax highlighting quickly becomes
940	wrong.
941	Example, to highlight the column where the cursor currently is: >
942		:exe '/\%' . col(".") . 'c'
943<	When 'hlsearch' is set and you move the cursor around and make changes
944	this will clearly show when the match is updated or not.
945	Example for matching a single byte in column 44: >
946		/\%>43c.\%<46c
947<	Note that "\%<46c" matches in column 45 when the "." matches a byte in
948	column 44.
949						*/\%v* */\%>v* */\%<v*
950\%23v	Matches in a specific virtual column.
951\%<23v	Matches before a specific virtual column.
952\%>23v	Matches after a specific virtual column.
953	These three can be used to match specific virtual columns in a buffer
954	or string.  When not matching with a buffer in a window, the option
955	values of the current window are used (e.g., 'tabstop').
956	The "23" can be any column number.  The first column is 1.
957	Note that some virtual column positions will never match, because they
958	are halfway through a tab or other character that occupies more than
959	one screen character.  {not in Vi}
960	WARNING: When inserting or deleting text Vim does not automatically
961	update highlighted matches.  This means Syntax highlighting quickly
962	becomes wrong.
963	Example, to highlight all the characters after virtual column 72: >
964		/\%>72v.*
965<	When 'hlsearch' is set and you move the cursor around and make changes
966	this will clearly show when the match is updated or not.
967	To match the text up to column 17: >
968		/^.*\%17v
969<	Column 17 is not included, because this is a |/zero-width| match. To
970	include the column use: >
971		/^.*\%17v.
972<	This command does the same thing, but also matches when there is no
973	character in column 17: >
974		/^.*\%<18v.
975<	Note that without the "^" to anchor the match in the first column,
976	this will also highlight column 17: >
977		/.*\%17v
978<	Column 17 is highlighted by 'hlsearch' because there is another match
979	where ".*" matches zero characters.
980<
981
982Character classes: {not in Vi}
983\i	identifier character (see 'isident' option)	*/\i*
984\I	like "\i", but excluding digits			*/\I*
985\k	keyword character (see 'iskeyword' option)	*/\k*
986\K	like "\k", but excluding digits			*/\K*
987\f	file name character (see 'isfname' option)	*/\f*
988\F	like "\f", but excluding digits			*/\F*
989\p	printable character (see 'isprint' option)	*/\p*
990\P	like "\p", but excluding digits			*/\P*
991
992NOTE: the above also work for multi-byte characters.  The ones below only
993match ASCII characters, as indicated by the range.
994
995						*whitespace* *white-space*
996\s	whitespace character: <Space> and <Tab>		*/\s*
997\S	non-whitespace character; opposite of \s	*/\S*
998\d	digit:				[0-9]		*/\d*
999\D	non-digit:			[^0-9]		*/\D*
1000\x	hex digit:			[0-9A-Fa-f]	*/\x*
1001\X	non-hex digit:			[^0-9A-Fa-f]	*/\X*
1002\o	octal digit:			[0-7]		*/\o*
1003\O	non-octal digit:		[^0-7]		*/\O*
1004\w	word character:			[0-9A-Za-z_]	*/\w*
1005\W	non-word character:		[^0-9A-Za-z_]	*/\W*
1006\h	head of word character:		[A-Za-z_]	*/\h*
1007\H	non-head of word character:	[^A-Za-z_]	*/\H*
1008\a	alphabetic character:		[A-Za-z]	*/\a*
1009\A	non-alphabetic character:	[^A-Za-z]	*/\A*
1010\l	lowercase character:		[a-z]		*/\l*
1011\L	non-lowercase character:	[^a-z]		*/\L*
1012\u	uppercase character:		[A-Z]		*/\u*
1013\U	non-uppercase character:	[^A-Z]		*/\U*
1014
1015	NOTE: Using the atom is faster than the [] form.
1016
1017	NOTE: 'ignorecase', "\c" and "\C" are not used by character classes.
1018
1019			*/\_* *E63* */\_i* */\_I* */\_k* */\_K* */\_f* */\_F*
1020			*/\_p* */\_P* */\_s* */\_S* */\_d* */\_D* */\_x* */\_X*
1021			*/\_o* */\_O* */\_w* */\_W* */\_h* */\_H* */\_a* */\_A*
1022			*/\_l* */\_L* */\_u* */\_U*
1023\_x	Where "x" is any of the characters above: The character class with
1024	end-of-line added
1025(end of character classes)
1026
1027\e	matches <Esc>					*/\e*
1028\t	matches <Tab>					*/\t*
1029\r	matches <CR>					*/\r*
1030\b	matches <BS>					*/\b*
1031\n	matches an end-of-line				*/\n*
1032	When matching in a string instead of buffer text a literal newline
1033	character is matched.
1034
1035~	matches the last given substitute string	*/~* */\~*
1036
1037\(\)	A pattern enclosed by escaped parentheses.	*/\(* */\(\)* */\)*
1038	E.g., "\(^a\)" matches 'a' at the start of a line.
1039	*E51* *E54* *E55* *E872* *E873*
1040
1041\1      Matches the same string that was matched by	*/\1* *E65*
1042	the first sub-expression in \( and \). {not in Vi}
1043	Example: "\([a-z]\).\1" matches "ata", "ehe", "tot", etc.
1044\2      Like "\1", but uses second sub-expression,	*/\2*
1045   ...							*/\3*
1046\9      Like "\1", but uses ninth sub-expression.	*/\9*
1047	Note: The numbering of groups is done based on which "\(" comes first
1048	in the pattern (going left to right), NOT based on what is matched
1049	first.
1050
1051\%(\)	A pattern enclosed by escaped parentheses.	*/\%(\)* */\%(* *E53*
1052	Just like \(\), but without counting it as a sub-expression.  This
1053	allows using more groups and it's a little bit faster.
1054	{not in Vi}
1055
1056x	A single character, with no special meaning, matches itself
1057
1058							*/\* */\\*
1059\x	A backslash followed by a single character, with no special meaning,
1060	is reserved for future expansions
1061
1062[]	(with 'nomagic': \[])		*/[]* */\[]* */\_[]* */collection*
1063\_[]
1064	A collection.  This is a sequence of characters enclosed in brackets.
1065	It matches any single character in the collection.
1066	Example		matches ~
1067	[xyz]		any 'x', 'y' or 'z'
1068	[a-zA-Z]$	any alphabetic character at the end of a line
1069	\c[a-z]$	same
1070	[А-яЁё]		Russian alphabet (with utf-8 and cp1251)
1071
1072								*/[\n]*
1073	With "\_" prepended the collection also includes the end-of-line.
1074	The same can be done by including "\n" in the collection.  The
1075	end-of-line is also matched when the collection starts with "^"!  Thus
1076	"\_[^ab]" matches the end-of-line and any character but "a" and "b".
1077	This makes it Vi compatible: Without the "\_" or "\n" the collection
1078	does not match an end-of-line.
1079								*E769*
1080	When the ']' is not there Vim will not give an error message but
1081	assume no collection is used.  Useful to search for '['.  However, you
1082	do get E769 for internal searching.  And be aware that in a
1083	`:substitute` command the whole command becomes the pattern.  E.g.
1084	":s/[/x/" searches for "[/x" and replaces it with nothing.  It does
1085	not search for "[" and replaces it with "x"!
1086
1087								*E944* *E945*
1088	If the sequence begins with "^", it matches any single character NOT
1089	in the collection: "[^xyz]" matches anything but 'x', 'y' and 'z'.
1090	- If two characters in the sequence are separated by '-', this is
1091	  shorthand for the full list of ASCII characters between them.  E.g.,
1092	  "[0-9]" matches any decimal digit. If the starting character exceeds
1093	  the ending character, e.g. [c-a], E944 occurs. Non-ASCII characters
1094	  can be used, but the character values must not be more than 256 apart
1095	  in the old regexp engine. For example, searching by [\u3000-\u4000]
1096	  after setting re=1 emits a E945 error. Prepending \%#=2 will fix it.
1097	- A character class expression is evaluated to the set of characters
1098	  belonging to that character class.  The following character classes
1099	  are supported:
1100		  Name	      Func	Contents ~
1101*[:alnum:]*	  [:alnum:]   isalnum	ASCII letters and digits
1102*[:alpha:]*	  [:alpha:]   isalpha  	ASCII letters
1103*[:blank:]*	  [:blank:]     	space and tab
1104*[:cntrl:]*	  [:cntrl:]   iscntrl 	ASCII control characters
1105*[:digit:]*	  [:digit:]     	decimal digits '0' to '9'
1106*[:graph:]*	  [:graph:]   isgraph	ASCII printable characters excluding
1107					space
1108*[:lower:]*	  [:lower:]   (1)	lowercase letters (all letters when
1109					'ignorecase' is used)
1110*[:print:]*	  [:print:]   (2) 	printable characters including space
1111*[:punct:]*	  [:punct:]   ispunct	ASCII punctuation characters
1112*[:space:]*	  [:space:]     	whitespace characters: space, tab, CR,
1113					NL, vertical tab, form feed
1114*[:upper:]*	  [:upper:]   (3)	uppercase letters (all letters when
1115					'ignorecase' is used)
1116*[:xdigit:]*	  [:xdigit:]    	hexadecimal digits: 0-9, a-f, A-F
1117*[:return:]*	  [:return:]		the <CR> character
1118*[:tab:]*	  [:tab:]		the <Tab> character
1119*[:escape:]*	  [:escape:]		the <Esc> character
1120*[:backspace:]*	  [:backspace:]		the <BS> character
1121	  The brackets in character class expressions are additional to the
1122	  brackets delimiting a collection.  For example, the following is a
1123	  plausible pattern for a UNIX filename: "[-./[:alnum:]_~]\+" That is,
1124	  a list of at least one character, each of which is either '-', '.',
1125	  '/', alphabetic, numeric, '_' or '~'.
1126	  These items only work for 8-bit characters, except [:lower:] and
1127	  [:upper:] also work for multi-byte characters when using the new
1128	  regexp engine.  See |two-engines|.  In the future these items may
1129	  work for multi-byte characters.  For now, to get all "alpha"
1130	  characters you can use: [[:lower:][:upper:]].
1131
1132	  The "Func" column shows what library function is used.  The
1133	  implementation depends on the system.  Otherwise:
1134	  (1) Uses islower() for ASCII and Vim builtin rules for other
1135	  characters when built with the |+multi_byte| feature.
1136	  (2) Uses Vim builtin rules
1137	  (3) As with (1) but using isupper()
1138							*/[[=* *[==]*
1139	- An equivalence class.  This means that characters are matched that
1140	  have almost the same meaning, e.g., when ignoring accents.  This
1141	  only works for Unicode, latin1 and latin9.  The form is:
1142		[=a=]
1143							*/[[.* *[..]*
1144	- A collation element.  This currently simply accepts a single
1145	  character in the form:
1146		[.a.]
1147							  */\]*
1148	- To include a literal ']', '^', '-' or '\' in the collection, put a
1149	  backslash before it: "[xyz\]]", "[\^xyz]", "[xy\-z]" and "[xyz\\]".
1150	  (Note: POSIX does not support the use of a backslash this way).  For
1151	  ']' you can also make it the first character (following a possible
1152	  "^"):  "[]xyz]" or "[^]xyz]" {not in Vi}.
1153	  For '-' you can also make it the first or last character: "[-xyz]",
1154	  "[^-xyz]" or "[xyz-]".  For '\' you can also let it be followed by
1155	  any character that's not in "^]-\bdertnoUux".  "[\xyz]" matches '\',
1156	  'x', 'y' and 'z'.  It's better to use "\\" though, future expansions
1157	  may use other characters after '\'.
1158	- Omitting the trailing ] is not considered an error. "[]" works like
1159	  "[]]", it matches the ']' character.
1160	- The following translations are accepted when the 'l' flag is not
1161	  included in 'cpoptions' {not in Vi}:
1162		\e	<Esc>
1163		\t	<Tab>
1164		\r	<CR>	(NOT end-of-line!)
1165		\b	<BS>
1166		\n	line break, see above |/[\n]|
1167		\d123	decimal number of character
1168		\o40	octal number of character up to 0377
1169		\x20	hexadecimal number of character up to 0xff
1170		\u20AC	hex. number of multibyte character up to 0xffff
1171		\U1234	hex. number of multibyte character up to 0xffffffff
1172	  NOTE: The other backslash codes mentioned above do not work inside
1173	  []!
1174	- Matching with a collection can be slow, because each character in
1175	  the text has to be compared with each character in the collection.
1176	  Use one of the other atoms above when possible.  Example: "\d" is
1177	  much faster than "[0-9]" and matches the same characters.  However,
1178	  the new |NFA| regexp engine deals with this better than the old one.
1179
1180						*/\%[]* *E69* *E70* *E369*
1181\%[]	A sequence of optionally matched atoms.  This always matches.
1182	It matches as much of the list of atoms it contains as possible.  Thus
1183	it stops at the first atom that doesn't match.  For example: >
1184		/r\%[ead]
1185<	matches "r", "re", "rea" or "read".  The longest that matches is used.
1186	To match the Ex command "function", where "fu" is required and
1187	"nction" is optional, this would work: >
1188		/\<fu\%[nction]\>
1189<	The end-of-word atom "\>" is used to avoid matching "fu" in "full".
1190	It gets more complicated when the atoms are not ordinary characters.
1191	You don't often have to use it, but it is possible.  Example: >
1192		/\<r\%[[eo]ad]\>
1193<	Matches the words "r", "re", "ro", "rea", "roa", "read" and "road".
1194	There can be no \(\), \%(\) or \z(\) items inside the [] and \%[] does
1195	not nest.
1196	To include a "[" use "[[]" and for "]" use []]", e.g.,: >
1197		/index\%[[[]0[]]]
1198<	matches "index" "index[", "index[0" and "index[0]".
1199	{not available when compiled without the |+syntax| feature}
1200
1201				*/\%d* */\%x* */\%o* */\%u* */\%U* *E678*
1202
1203\%d123	Matches the character specified with a decimal number.  Must be
1204	followed by a non-digit.
1205\%o40	Matches the character specified with an octal number up to 0377.
1206	Numbers below 040 must be followed by a non-octal digit or a non-digit.
1207\%x2a	Matches the character specified with up to two hexadecimal characters.
1208\%u20AC	Matches the character specified with up to four hexadecimal
1209	characters.
1210\%U1234abcd	Matches the character specified with up to eight hexadecimal
1211	characters.
1212
1213==============================================================================
12147. Ignoring case in a pattern					*/ignorecase*
1215
1216If the 'ignorecase' option is on, the case of normal letters is ignored.
1217'smartcase' can be set to ignore case when the pattern contains lowercase
1218letters only.
1219							*/\c* */\C*
1220When "\c" appears anywhere in the pattern, the whole pattern is handled like
1221'ignorecase' is on.  The actual value of 'ignorecase' and 'smartcase' is
1222ignored.  "\C" does the opposite: Force matching case for the whole pattern.
1223{only Vim supports \c and \C}
1224Note that 'ignorecase', "\c" and "\C" are not used for the character classes.
1225
1226Examples:
1227      pattern	'ignorecase'  'smartcase'	matches ~
1228	foo	  off		-		foo
1229	foo	  on		-		foo Foo FOO
1230	Foo	  on		off		foo Foo FOO
1231	Foo	  on		on		    Foo
1232	\cfoo	  -		-		foo Foo FOO
1233	foo\C	  -		-		foo
1234
1235Technical detail:				*NL-used-for-Nul*
1236<Nul> characters in the file are stored as <NL> in memory.  In the display
1237they are shown as "^@".  The translation is done when reading and writing
1238files.  To match a <Nul> with a search pattern you can just enter CTRL-@ or
1239"CTRL-V 000".  This is probably just what you expect.  Internally the
1240character is replaced with a <NL> in the search pattern.  What is unusual is
1241that typing CTRL-V CTRL-J also inserts a <NL>, thus also searches for a <Nul>
1242in the file.  {Vi cannot handle <Nul> characters in the file at all}
1243
1244						*CR-used-for-NL*
1245When 'fileformat' is "mac", <NL> characters in the file are stored as <CR>
1246characters internally.  In the text they are shown as "^J".  Otherwise this
1247works similar to the usage of <NL> for a <Nul>.
1248
1249When working with expression evaluation, a <NL> character in the pattern
1250matches a <NL> in the string.  The use of "\n" (backslash n) to match a <NL>
1251doesn't work there, it only works to match text in the buffer.
1252
1253						*pattern-multi-byte*
1254Patterns will also work with multi-byte characters, mostly as you would
1255expect.  But invalid bytes may cause trouble, a pattern with an invalid byte
1256will probably never match.
1257
1258==============================================================================
12598. Composing characters					*patterns-composing*
1260
1261							*/\Z*
1262When "\Z" appears anywhere in the pattern, all composing characters are
1263ignored.  Thus only the base characters need to match, the composing
1264characters may be different and the number of composing characters may differ.
1265Only relevant when 'encoding' is "utf-8".
1266Exception: If the pattern starts with one or more composing characters, these
1267must match.
1268							*/\%C*
1269Use "\%C" to skip any composing characters.  For example, the pattern "a" does
1270not match in "càt" (where the a has the composing character 0x0300), but
1271"a\%C" does.  Note that this does not match "cát" (where the á is character
12720xe1, it does not have a compositing character).  It does match "cat" (where
1273the a is just an a).
1274
1275When a composing character appears at the start of the pattern of after an
1276item that doesn't include the composing character, a match is found at any
1277character that includes this composing character.
1278
1279When using a dot and a composing character, this works the same as the
1280composing character by itself, except that it doesn't matter what comes before
1281this.
1282
1283The order of composing characters does not matter.  Also, the text may have
1284more composing characters than the pattern, it still matches.  But all
1285composing characters in the pattern must be found in the text.
1286
1287Suppose B is a base character and x and y are composing characters:
1288	pattern		text		match ~
1289	Bxy		Bxy		yes (perfect match)
1290	Bxy		Byx		yes (order ignored)
1291	Bxy		By		no (x missing)
1292	Bxy		Bx		no (y missing)
1293	Bx		Bx		yes (perfect match)
1294	Bx		By		no (x missing)
1295	Bx		Bxy		yes (extra y ignored)
1296	Bx		Byx		yes (extra y ignored)
1297
1298==============================================================================
12999. Compare with Perl patterns				*perl-patterns*
1300
1301Vim's regexes are most similar to Perl's, in terms of what you can do.  The
1302difference between them is mostly just notation;  here's a summary of where
1303they differ:
1304
1305Capability			in Vimspeak	in Perlspeak ~
1306----------------------------------------------------------------
1307force case insensitivity	\c		(?i)
1308force case sensitivity		\C		(?-i)
1309backref-less grouping		\%(atom\)	(?:atom)
1310conservative quantifiers	\{-n,m}		*?, +?, ??, {}?
13110-width match			atom\@=		(?=atom)
13120-width non-match		atom\@!		(?!atom)
13130-width preceding match		atom\@<=	(?<=atom)
13140-width preceding non-match	atom\@<!	(?<!atom)
1315match without retry		atom\@>		(?>atom)
1316
1317Vim and Perl handle newline characters inside a string a bit differently:
1318
1319In Perl, ^ and $ only match at the very beginning and end of the text,
1320by default, but you can set the 'm' flag, which lets them match at
1321embedded newlines as well.  You can also set the 's' flag, which causes
1322a . to match newlines as well.  (Both these flags can be changed inside
1323a pattern using the same syntax used for the i flag above, BTW.)
1324
1325On the other hand, Vim's ^ and $ always match at embedded newlines, and
1326you get two separate atoms, \%^ and \%$, which only match at the very
1327start and end of the text, respectively.  Vim solves the second problem
1328by giving you the \_ "modifier":  put it in front of a . or a character
1329class, and they will match newlines as well.
1330
1331Finally, these constructs are unique to Perl:
1332- execution of arbitrary code in the regex:  (?{perl code})
1333- conditional expressions:  (?(condition)true-expr|false-expr)
1334
1335...and these are unique to Vim:
1336- changing the magic-ness of a pattern:  \v \V \m \M
1337   (very useful for avoiding backslashitis)
1338- sequence of optionally matching atoms:  \%[atoms]
1339- \& (which is to \| what "and" is to "or";  it forces several branches
1340   to match at one spot)
1341- matching lines/columns by number:  \%5l \%5c \%5v
1342- setting the start and end of the match:  \zs \ze
1343
1344==============================================================================
134510. Highlighting matches				*match-highlight*
1346
1347							*:mat* *:match*
1348:mat[ch] {group} /{pattern}/
1349		Define a pattern to highlight in the current window.  It will
1350		be highlighted with {group}.  Example: >
1351			:highlight MyGroup ctermbg=green guibg=green
1352			:match MyGroup /TODO/
1353<		Instead of // any character can be used to mark the start and
1354		end of the {pattern}.  Watch out for using special characters,
1355		such as '"' and '|'.
1356
1357		{group} must exist at the moment this command is executed.
1358
1359		The {group} highlighting still applies when a character is
1360		to be highlighted for 'hlsearch', as the highlighting for
1361		matches is given higher priority than that of 'hlsearch'.
1362		Syntax highlighting (see 'syntax') is also overruled by
1363		matches.
1364
1365		Note that highlighting the last used search pattern with
1366		'hlsearch' is used in all windows, while the pattern defined
1367		with ":match" only exists in the current window.  It is kept
1368		when switching to another buffer.
1369
1370		'ignorecase' does not apply, use |/\c| in the pattern to
1371		ignore case.  Otherwise case is not ignored.
1372
1373		'redrawtime' defines the maximum time searched for pattern
1374		matches.
1375
1376		When matching end-of-line and Vim redraws only part of the
1377		display you may get unexpected results.  That is because Vim
1378		looks for a match in the line where redrawing starts.
1379
1380		Also see |matcharg()| and |getmatches()|. The former returns
1381		the highlight group and pattern of a previous |:match|
1382		command.  The latter returns a list with highlight groups and
1383		patterns defined by both |matchadd()| and |:match|.
1384
1385		Highlighting matches using |:match| are limited to three
1386		matches (aside from |:match|, |:2match| and |:3match| are
1387		available). |matchadd()| does not have this limitation and in
1388		addition makes it possible to prioritize matches.
1389
1390		Another example, which highlights all characters in virtual
1391		column 72 and more: >
1392			:highlight rightMargin term=bold ctermfg=blue guifg=blue
1393			:match rightMargin /.\%>72v/
1394<		To highlight all character that are in virtual column 7: >
1395			:highlight col8 ctermbg=grey guibg=grey
1396			:match col8 /\%<8v.\%>7v/
1397<		Note the use of two items to also match a character that
1398		occupies more than one virtual column, such as a TAB.
1399
1400:mat[ch]
1401:mat[ch] none
1402		Clear a previously defined match pattern.
1403
1404
1405:2mat[ch] {group} /{pattern}/					*:2match*
1406:2mat[ch]
1407:2mat[ch] none
1408:3mat[ch] {group} /{pattern}/					*:3match*
1409:3mat[ch]
1410:3mat[ch] none
1411		Just like |:match| above, but set a separate match.  Thus
1412		there can be three matches active at the same time.  The match
1413		with the lowest number has priority if several match at the
1414		same position.
1415		The ":3match" command is used by the |matchparen| plugin.  You
1416		are suggested to use ":match" for manual matching and
1417		":2match" for another plugin.
1418
1419
1420 vim:tw=78:ts=8:noet:ft=help:norl:
1421