fold.txt For Vim version 7.4. Last change: 2013 Dec 04LINK

VIM REFERENCE MANUAL by Bram Moolenaar

Folding Folding folding foldsLINK

You can find an introduction on folding in chapter 28 of the user manual.

usr_28.txt

1. Fold methods fold-methods

2. Fold commands fold-commands

3. Fold options fold-options

4. Behavior of folds fold-behavior

{Vi has no Folding}

{not available when compiled without the +folding feature}

==============================================================================

1. Fold methods fold-methodsLINK

The folding method can be set with the 'foldmethod' option.

When setting 'foldmethod' to a value other than "manual", all folds are

deleted and new ones created. Switching to the "manual" method doesn't remove

the existing folds. This can be used to first define the folds automatically

and then change them manually.

There are six methods to select folds:

manual manually define folds

indent more indent means a higher fold level

expr specify an expression to define folds

syntax folds defined by syntax highlighting

diff folds for unchanged text

marker folds defined by markers in the text

MANUAL fold-manualLINK

Use commands to manually define the fold regions. This can also be used by a

script that parses text to find folds.

The level of a fold is only defined by its nesting. To increase the fold

level of a fold for a range of lines, define a fold inside it that has the

same lines.

The manual folds are lost when you abandon the file. To save the folds use

the :mkview command. The view can be restored later with :loadview.

INDENT fold-indentLINK

The folds are automatically defined by the indent of the lines.

The foldlevel is computed from the indent of the line, divided by the

'shiftwidth' (rounded down). A sequence of lines with the same or higher fold

level form a fold, with the lines with a higher level forming a nested fold.

The nesting of folds is limited with 'foldnestmax'.

Some lines are ignored and get the fold level of the line above or below it,

whichever is lower. These are empty or white lines and lines starting

with a character in 'foldignore'. White space is skipped before checking for

characters in 'foldignore'. For C use "#" to ignore preprocessor lines.

When you want to ignore lines in another way, use the 'expr' method. The

indent() function can be used in 'foldexpr' to get the indent of a line.

EXPR fold-exprLINK

The folds are automatically defined by their foldlevel, like with the "indent"

method. The value of the 'foldexpr' option is evaluated to get the foldlevel

of a line. Examples:

This will create a fold for all consecutive lines that start with a tab:

:set foldexpr=getline(v:lnum)[0]==\"\\t\"

This will call a function to compute the fold level:

:set foldexpr=MyFoldLevel(v:lnum)

This will make a fold out of paragraphs separated by blank lines:

:set foldexpr=getline(v:lnum)=~'^\\s*$'&&getline(v:lnum+1)=~'\\S'?'<1':1

this does the same:

:set foldexpr=getline(v:lnum-1)=~'^\\s*$'&&getline(v:lnum)=~'\\S'?'>1':1

Note that backslashes must be used to escape characters that ":set" handles

differently (space, backslash, double quote, etc., see option-backslash).

These are the conditions with which the expression is evaluated:

- The current buffer and window are set for the line.

- The variable "v:lnum" is set to the line number.

- The result is used for the fold level in this way:

value meaning

0 the line is not in a fold

1, 2, .. the line is in a fold with this level

-1 the fold level is undefined, use the fold level of a

line before or after this line, whichever is the

lowest.

"=" use fold level from the previous line

"a1", "a2", .. add one, two, .. to the fold level of the previous

line

"s1", "s2", .. subtract one, two, .. from the fold level of the

previous line

"<1", "<2", .. a fold with this level ends at this line

">1", ">2", .. a fold with this level starts at this line

It is not required to mark the start (end) of a fold with ">1" ("<1"), a fold

will also start (end) when the fold level is higher (lower) than the fold

level of the previous line.

There must be no side effects from the expression. The text in the buffer,

cursor position, the search patterns, options etc. must not be changed.

You can change and restore them if you are careful.

If there is some error in the expression, or the resulting value isn't

recognized, there is no error message and the fold level will be zero.

For debugging the 'debug' option can be set to "msg", the error messages will

be visible then.

Note: Since the expression has to be evaluated for every line, this fold

method can be very slow!

Try to avoid the "=", "a" and "s" return values, since Vim often has to search

backwards for a line for which the fold level is defined. This can be slow.

foldlevel() can be useful to compute a fold level relative to a previous

fold level. But note that foldlevel() may return -1 if the level is not known

yet. And it returns the level at the start of the line, while a fold might

end in that line.

It may happened that folds are not updated properly. You can use zx or zX

to force updating folds.

SYNTAX fold-syntaxLINK

A fold is defined by syntax items that have the "fold" argument. :syn-fold

The fold level is defined by nesting folds. The nesting of folds is limited

with 'foldnestmax'.

Be careful to specify proper syntax syncing. If this is not done right, folds

may differ from the displayed highlighting. This is especially relevant when

using patterns that match more than one line. In case of doubt, try using

brute-force syncing:

:syn sync fromstart

DIFF fold-diffLINK

The folds are automatically defined for text that is not part of a change or

close to a change.

This method only works properly when the 'diff' option is set for the current

window and changes are being displayed. Otherwise the whole buffer will be

one big fold.

The 'diffopt' option can be used to specify the context. That is, the number

of lines between the fold and a change that are not included in the fold. For

example, to use a context of 8 lines:

:set diffopt=filler,context:8

The default context is six lines.

When 'scrollbind' is also set, Vim will attempt to keep the same folds open in

other diff windows, so that the same text is visible.

MARKER fold-markerLINK

Markers in the text tell where folds start and end. This allows you to

precisely specify the folds. This will allow deleting and putting a fold,

without the risk of including the wrong lines. The 'foldtext' option is

normally set such that the text before the marker shows up in the folded line.

This makes it possible to give a name to the fold.

Markers can have a level included, or can use matching pairs. Including a

level is easier, you don't have to add end markers and avoid problems with

non-matching marker pairs. Example:

/* global variables {{{1 */

int varA, varB;

/* functions {{{1 */

/* funcA() {{{2 */

void funcA() {}

/* funcB() {{{2 */

void funcB() {}

A fold starts at a "{{{" marker. The following number specifies the fold

level. What happens depends on the difference between the current fold level

and the level given by the marker:

1. If a marker with the same fold level is encountered, the previous fold

ends and another fold with the same level starts.

2. If a marker with a higher fold level is found, a nested fold is started.

3. if a marker with a lower fold level is found, all folds up to and including

this level end and a fold with the specified level starts.

The number indicates the fold level. A zero cannot be used (a marker with

level zero is ignored). You can use "}}}" with a digit to indicate the level

of the fold that ends. The fold level of the following line will be one less

than the indicated level. Note that Vim doesn't look back to the level of the

matching marker (that would take too much time). Example:

{{{1

fold level here is 1

{{{3

fold level here is 3

}}}3

fold level here is 2

You can also use matching pairs of "{{{" and "}}}" markers to define folds.

Each "{{{" increases the fold level by one, each "}}}" decreases the fold

level by one. Be careful to keep the markers matching! Example:

{{{

fold level here is 1

{{{

fold level here is 2

}}}

fold level here is 1

You can mix using markers with a number and without a number. A useful way of

doing this is to use numbered markers for large folds, and unnumbered markers

locally in a function. For example use level one folds for the sections of

your file like "structure definitions", "local variables" and "functions".

Use level 2 markers for each definition and function, Use unnumbered markers

inside functions. When you make changes in a function to split up folds, you

don't have to renumber the markers.

The markers can be set with the 'foldmarker' option. It is recommended to

keep this at the default value of "{{{,}}}", so that files can be exchanged

between Vim users. Only change it when it is required for the file (e.g., it

contains markers from another folding editor, or the default markers cause

trouble for the language of the file).

fold-create-markerLINK

"zf" can be used to create a fold defined by markers. Vim will insert the

markers for you. Vim will append the start and end marker, as specified with

'foldmarker'. The markers are appended to the end of the line.

'commentstring' is used if it isn't empty.

This does not work properly when:

- The line already contains a marker with a level number. Vim then doesn't

know what to do.

- Folds nearby use a level number in their marker which gets in the way.

- The line is inside a comment, 'commentstring' isn't empty and nested

comments don't work. For example with C: adding /* {{{ */ inside a comment

will truncate the existing comment. Either put the marker before or after

the comment, or add the marker manually.

Generally it's not a good idea to let Vim create markers when you already have

markers with a level number.

fold-delete-markerLINK

"zd" can be used to delete a fold defined by markers. Vim will delete the

markers for you. Vim will search for the start and end markers, as specified

with 'foldmarker', at the start and end of the fold. When the text around the

marker matches with 'commentstring', that text is deleted as well.

This does not work properly when:

- A line contains more than one marker and one of them specifies a level.

Only the first one is removed, without checking if this will have the

desired effect of deleting the fold.

- The marker contains a level number and is used to start or end several folds

at the same time.

==============================================================================

2. Fold commands fold-commands E490LINK

All folding commands start with "z". Hint: the "z" looks like a folded piece

of paper, if you look at it from the side.

CREATING AND DELETING FOLDS

zf E350LINK

zf{motion} or

{Visual}zf Operator to create a fold.

This only works when 'foldmethod' is "manual" or "marker".

The new fold will be closed for the "manual" method.

'foldenable' will be set.

Also see fold-create-marker.

zFLINK

zF Create a fold for [count] lines. Works like "zf".

:{range}fo[ld] :fold :foLINK

Create a fold for the lines in {range}. Works like "zf".

zd E351LINK

zd Delete one fold at the cursor. When the cursor is on a folded

line, that fold is deleted. Nested folds are moved one level

up. In Visual mode one level of all folds (partially) in the

selected area are deleted.

Careful: This easily deletes more folds than you expect and

there is no undo for manual folding.

This only works when 'foldmethod' is "manual" or "marker".

Also see fold-delete-marker.

zDLINK

zD Delete folds recursively at the cursor. In Visual mode all

folds (partially) in the selected area and all nested folds in

them are deleted.

This only works when 'foldmethod' is "manual" or "marker".

Also see fold-delete-marker.

zE E352LINK

zE Eliminate all folds in the window.

This only works when 'foldmethod' is "manual" or "marker".

Also see fold-delete-marker.

OPENING AND CLOSING FOLDS

A fold smaller than 'foldminlines' will always be displayed like it was open.

Therefore the commands below may work differently on small folds.

zoLINK

zo Open one fold under the cursor. When a count is given, that

many folds deep will be opened. In Visual mode one level of

folds is opened for all lines in the selected area.

zOLINK

zO Open all folds under the cursor recursively. Folds that don't

contain the cursor line are unchanged.

In Visual mode it opens all folds that are in the selected

area, also those that are only partly selected.

zcLINK

zc Close one fold under the cursor. When a count is given, that

many folds deep are closed. In Visual mode one level of folds

is closed for all lines in the selected area.

'foldenable' will be set.

zCLINK

zC Close all folds under the cursor recursively. Folds that

don't contain the cursor line are unchanged.

In Visual mode it closes all folds that are in the selected

area, also those that are only partly selected.

'foldenable' will be set.

zaLINK

za When on a closed fold: open it. When folds are nested, you

may have to use "za" several times. When a count is given,

that many closed folds are opened.

When on an open fold: close it and set 'foldenable'. This

will only close one level, since using "za" again will open

the fold. When a count is given that many folds will be

closed (that's not the same as repeating "za" that many

times).

zALINK

zA When on a closed fold: open it recursively.

When on an open fold: close it recursively and set

'foldenable'.

zvLINK

zv View cursor line: Open just enough folds to make the line in

which the cursor is located not folded.

zxLINK

zx Update folds: Undo manually opened and closed folds: re-apply

'foldlevel', then do "zv": View cursor line.

Also forces recomputing folds. This is useful when using

'foldexpr' and the buffer is changed in a way that results in

folds not to be updated properly.

zXLINK

zX Undo manually opened and closed folds: re-apply 'foldlevel'.

Also forces recomputing folds, like zx.

zmLINK

zm Fold more: Subtract one from 'foldlevel'. If 'foldlevel' was

already zero nothing happens.

'foldenable' will be set.

zMLINK

zM Close all folds: set 'foldlevel' to 0.

'foldenable' will be set.

zrLINK

zr Reduce folding: Add one to 'foldlevel'.

zRLINK

zR Open all folds. This sets 'foldlevel' to highest fold level.

:foldo :foldopenLINK

:{range}foldo[pen][!]

Open folds in {range}. When [!] is added all folds are

opened. Useful to see all the text in {range}. Without [!]

one level of folds is opened.

:foldc :foldcloseLINK

:{range}foldc[lose][!]

Close folds in {range}. When [!] is added all folds are

closed. Useful to hide all the text in {range}. Without [!]

one level of folds is closed.

znLINK

zn Fold none: reset 'foldenable'. All folds will be open.

zNLINK

zN Fold normal: set 'foldenable'. All folds will be as they

were before.

ziLINK

zi Invert 'foldenable'.

MOVING OVER FOLDS

[zLINK

[z Move to the start of the current open fold. If already at the

start, move to the start of the fold that contains it. If

there is no containing fold, the command fails.

When a count is used, repeats the command [count] times.

]zLINK

]z Move to the end of the current open fold. If already at the

end, move to the end of the fold that contains it. If there

is no containing fold, the command fails.

When a count is used, repeats the command [count] times.

zjLINK

zj Move downwards to the start of the next fold. A closed fold

is counted as one fold.

When a count is used, repeats the command [count] times.

This command can be used after an operator.

zkLINK

zk Move upwards to the end of the previous fold. A closed fold

is counted as one fold.

When a count is used, repeats the command [count] times.

This command can be used after an operator.

EXECUTING COMMANDS ON FOLDS

:[range]foldd[oopen] {cmd} :foldd :folddoopenLINK

Execute {cmd} on all lines that are not in a closed fold.

When [range] is given, only these lines are used.

Each time {cmd} is executed the cursor is positioned on the

line it is executed for.

This works like the ":global" command: First all lines that

are not in a closed fold are marked. Then the {cmd} is

executed for all marked lines. Thus when {cmd} changes the

folds, this has no influence on where it is executed (except

when lines are deleted, of course).

Example:

:folddoopen s/end/loop_end/ge

Note the use of the "e" flag to avoid getting an error message

where "end" doesn't match.

:[range]folddoc[losed] {cmd} :folddoc :folddoclosedLINK

Execute {cmd} on all lines that are in a closed fold.

Otherwise like ":folddoopen".

==============================================================================

3. Fold options fold-optionsLINK

COLORS fold-colorsLINK

The colors of a closed fold are set with the Folded group hl-Folded. The

colors of the fold column are set with the FoldColumn group hl-FoldColumn.

Example to set the colors:

:highlight Folded guibg=grey guifg=blue

:highlight FoldColumn guibg=darkgrey guifg=white

FOLDLEVEL fold-foldlevelLINK

'foldlevel' is a number option: The higher the more folded regions are open.

When 'foldlevel' is 0, all folds are closed.

When 'foldlevel' is positive, some folds are closed.

When 'foldlevel' is very high, all folds are open.

'foldlevel' is applied when it is changed. After that manually folds can be

opened and closed.

When increased, folds above the new level are opened. No manually opened

folds will be closed.

When decreased, folds above the new level are closed. No manually closed

folds will be opened.

FOLDTEXT fold-foldtextLINK

'foldtext' is a string option that specifies an expression. This expression

is evaluated to obtain the text displayed for a closed fold. Example:

:set foldtext=v:folddashes.substitute(getline(v:foldstart),'/\\*\\\|\\*/\\\|{{{\\d\\=','','g')

This shows the first line of the fold, with "/*", "*/" and "{{{" removed.

Note the use of backslashes to avoid some characters to be interpreted by the

":set" command. It's simpler to define a function and call that:

:set foldtext=MyFoldText()

:function MyFoldText()

: let line = getline(v:foldstart)

: let sub = substitute(line, '/\*\|\*/\|{{{\d\=', '', 'g')

: return v:folddashes . sub

:endfunction

Evaluating 'foldtext' is done in the sandbox. The current window is set to

the window that displays the line. Errors are ignored.

The default value is foldtext(). This returns a reasonable text for most

types of folding. If you don't like it, you can specify your own 'foldtext'

expression. It can use these special Vim variables:

v:foldstart line number of first line in the fold

v:foldend line number of last line in the fold

v:folddashes a string that contains dashes to represent the

foldlevel.

v:foldlevel the foldlevel of the fold

In the result a TAB is replaced with a space and unprintable characters are

made into printable characters.

The resulting line is truncated to fit in the window, it never wraps.

When there is room after the text, it is filled with the character specified

by 'fillchars'.

Note that backslashes need to be used for characters that the ":set" command

handles differently: Space, backslash and double-quote. option-backslash

FOLDCOLUMN fold-foldcolumnLINK

'foldcolumn' is a number, which sets the width for a column on the side of the

window to indicate folds. When it is zero, there is no foldcolumn. A normal

value is 4 or 5. The minimal useful value is 2, although 1 still provides

some information. The maximum is 12.

An open fold is indicated with a column that has a '-' at the top and '|'

characters below it. This column stops where the open fold stops. When folds

nest, the nested fold is one character right of the fold it's contained in.

A closed fold is indicated with a '+'.

Where the fold column is too narrow to display all nested folds, digits are

shown to indicate the nesting level.

The mouse can also be used to open and close folds by clicking in the

fold column:

- Click on a '+' to open the closed fold at this row.

- Click on any other non-blank character to close the open fold at this row.

OTHER OPTIONS

'foldenable' 'fen': Open all folds while not set.

'foldexpr' 'fde': Expression used for "expr" folding.

'foldignore' 'fdi': Characters used for "indent" folding.

'foldmarker' 'fmr': Defined markers used for "marker" folding.

'foldmethod' 'fdm': Name of the current folding method.

'foldminlines' 'fml': Minimum number of screen lines for a fold to be

displayed closed.

'foldnestmax' 'fdn': Maximum nesting for "indent" and "syntax" folding.

'foldopen' 'fdo': Which kinds of commands open closed folds.

'foldclose' 'fcl': When the folds not under the cursor are closed.

==============================================================================

4. Behavior of folds fold-behaviorLINK

When moving the cursor upwards or downwards and when scrolling, the cursor

will move to the first line of a sequence of folded lines. When the cursor is

already on a folded line, it moves to the next unfolded line or the next

closed fold.

While the cursor is on folded lines, the cursor is always displayed in the

first column. The ruler does show the actual cursor position, but since the

line is folded, it cannot be displayed there.

Many movement commands handle a sequence of folded lines like an empty line.

For example, the "w" command stops once in the first column.

When in Insert mode, the cursor line is never folded. That allows you to see

what you type!

When using an operator, a closed fold is included as a whole. Thus "dl"

deletes the whole closed fold under the cursor.

For Ex commands the range is adjusted to always start at the first line of a

closed fold and end at the last line of a closed fold. Thus this command:

:s/foo/bar/g

when used with the cursor on a closed fold, will replace "foo" with "bar" in

all lines of the fold.

This does not happen for :folddoopen and :folddoclosed.

When editing a buffer that has been edited before, the last used folding

settings are used again. For manual folding the defined folds are restored.

For all folding methods the manually opened and closed folds are restored.

If this buffer has been edited in this window, the values from back then are

used. Otherwise the values from the window where the buffer was edited last

are used.

==============================================================================

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