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junegunn/vim-easy-align: A Vim alignment plugin #78

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yaohunzhanyue opened this issue Apr 22, 2020 · 0 comments
Open

junegunn/vim-easy-align: A Vim alignment plugin #78

yaohunzhanyue opened this issue Apr 22, 2020 · 0 comments
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@yaohunzhanyue
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vim-easy-align

A simple, easy-to-use Vim alignment plugin.


Installation

Use your favorite plugin manager.

Using vim-plug:

Plug 'junegunn/vim-easy-align'

Quick start guide

Add the following mappings to your .vimrc.

" Start interactive EasyAlign in visual mode (e.g. vipga)
xmap ga <Plug>(EasyAlign)

" Start interactive EasyAlign for a motion/text object (e.g. gaip)
nmap ga <Plug>(EasyAlign)

Then with the following lines of text,

apple   =red
grass+=green
sky-=   blue

try these commands:

  • vipga=
    • visual-select inner paragraph
    • Start EasyAlign command (ga)
    • Align around =
  • gaip=
    • Start EasyAlign command (ga) for inner paragraph
    • Align around =

Demo

Click on each image to see from the beginning.

Using predefined alignment rules

An alignment rule is a predefined set of options for common alignment tasks, which is identified by a single character, such as <Space>, =, :, ., |, &, #, and ,.

=


  • = Around the 1st occurrences
  • 2= Around the 2nd occurrences
  • *= Around all occurrences
  • **= Left/Right alternating alignment around all occurrences
  • <Enter> Switching between left/right/center alignment modes

<Space>


  • <Space> Around the 1st occurrences of whitespaces
  • 2<Space> Around the 2nd occurrences
  • -<Space> Around the last occurrences
  • <Enter><Enter>2<Space> Center-alignment around the 2nd occurrences

,


  • The predefined comma-rule places a comma right next to the preceding token without margin ({'stick_to_left': 1, 'left_margin': 0})
  • You can change it with <Right> arrow

Using regular expression


You can use an arbitrary regular expression by

  • pressing <Ctrl-X> in interactive mode
  • or using :EasyAlign /REGEX/ command in visual mode or in normal mode with a range (e.g. :%)

Different ways to start


This demo shows how you can start interactive mode with visual selection or use non-interactive :EasyAlign command.

Aligning table cells


Check out various alignment options and "live interactive mode".

Syntax-aware alignment


Delimiters in strings and comments are ignored by default.

Using blockwise-visual mode


You can limit the scope with blockwise-visual mode.

Usage

Flow of execution


There are two ways to use easy-align.

1. <Plug> mappings (interactive mode)

The recommended method is to use <Plug>(EasyAlign) mapping in normal and visual mode. They are usually mapped to ga, but you can choose any key sequences.

nmap ga <Plug>(EasyAlign)
xmap ga <Plug>(EasyAlign)
  1. ga key in visual mode, or ga followed by a motion or a text object to start interactive mode
  2. (Optional) Enter keys to cycle between alignment mode (left, right, or center)
  3. (Optional) N-th delimiter (default: 1)
    • 1 Around the 1st occurrences of delimiters
    • 2 Around the 2nd occurrences of delimiters
    • ...
    • * Around all occurrences of delimiters
    • ** Left-right alternating alignment around all delimiters
    • - Around the last occurrences of delimiters (-1)
    • -2 Around the second to last occurrences of delimiters
    • ...
  4. Delimiter key (a single keystroke; <Space>, =, :, ., |, &, #, ,) or an arbitrary regular expression followed by <CTRL-X>

2. Using :EasyAlign command

If you prefer command-line, use :EasyAlign command instead.

" Using predefined rules
:EasyAlign[!] [N-th] DELIMITER_KEY [OPTIONS]

" Using regular expression
:EasyAlign[!] [N-th] /REGEXP/ [OPTIONS]

Regular expression vs. predefined rules

You can use regular expressions but it's usually much easier to use predefined alignment rules that you can trigger with a single keystroke.

Key Description/Use cases
<Space> General alignment around whitespaces
= Operators containing equals sign (=, ==, !=, +=, &&=, ...)
: Suitable for formatting JSON or YAML
. Multi-line method chaining
, Multi-line method arguments
& LaTeX tables (matches & and \\)
# Ruby/Python comments
" Vim comments
<Bar> Table markdown

You can also define your own rules with g:easy_align_delimiters which will be described in the later section.

Interactive mode

Interactive mode is started either with <Plug>(EasyAlign) mapping or with :EasyAlign command with no argument.

Examples using predefined rules

Keystrokes Description Equivalent command
<Space> Around 1st whitespaces :'<,'>EasyAlign\
2<Space> Around 2nd whitespaces :'<,'>EasyAlign2\
-<Space> Around the last whitespaces :'<,'>EasyAlign-\
-2<Space> Around the 2nd to last whitespaces :'<,'>EasyAlign-2\
: Around 1st colon (key: value) :'<,'>EasyAlign:
<Right>: Around 1st colon (key : value) :'<,'>EasyAlign:>l1
= Around 1st operators with = :'<,'>EasyAlign=
3= Around 3rd operators with = :'<,'>EasyAlign3=
*= Around all operators with = :'<,'>EasyAlign*=
**= Left-right alternating around = :'<,'>EasyAlign**=
<Enter>= Right alignment around 1st = :'<,'>EasyAlign!=
<Enter>**= Right-left alternating around = :'<,'>EasyAlign!**=

Instead of finishing the alignment with a delimiter key, you can type in a regular expression if you press <CTRL-/> or <CTRL-X>.

Alignment options in interactive mode

While in interactive mode, you can set alignment options using special shortcut keys listed below. The meaning of each option will be described in the following sections.

Key Option Values
CTRL-F filter Input string ([gv]/.*/?)
CTRL-I indentation shallow, deep, none, keep
CTRL-L left_margin Input number or string
CTRL-R right_margin Input number or string
CTRL-D delimiter_align left, center, right
CTRL-U ignore_unmatched 0, 1
CTRL-G ignore_groups [], ['String'], ['Comment'], ['String', 'Comment']
CTRL-A align Input string (/[lrc]+\*{0,2}/)
<Left> stick_to_left { 'stick_to_left': 1, 'left_margin': 0 }
<Right> stick_to_left { 'stick_to_left': 0, 'left_margin': 1 }
<Down> *_margin { 'left_margin': 0, 'right_margin': 0 }

Live interactive mode

If you're performing a complex alignment where multiple options should be carefully adjusted, try "live interactive mode" where you can preview the result of the alignment on-the-fly as you type in.

Live interactive mode can be started with either <Plug>(LiveEasyAlign) map or :LiveEasyAlign command. Or you can switch to live interactive mode while in ordinary interactive mode by pressing <CTRL-P>. (P for Preview)

In live interactive mode, you have to type in the same delimiter (or <CTRL-X> on regular expression) again to finalize the alignment. This allows you to preview the result of the alignment and freely change the delimiter using backspace key without leaving the interactive mode.

:EasyAlign command

Instead of starting interactive mode, you can use non-interactive :EasyAlign command.

" Using predefined alignment rules
"   :EasyAlign[!] [N-th] DELIMITER_KEY [OPTIONS]
:EasyAlign :
:EasyAlign =
:EasyAlign *=
:EasyAlign 3\

" Using arbitrary regular expressions
"   :EasyAlign[!] [N-th] /REGEXP/ [OPTIONS]
:EasyAlign /[:;]\+/
:EasyAlign 2/[:;]\+/
:EasyAlign */[:;]\+/
:EasyAlign **/[:;]\+/

A command can end with alignment options, each of which will be discussed in detail later, in Vim dictionary format.

  • :EasyAlign * /[:;]\+/ { 'stick_to_left': 1, 'left_margin': 0 }

stick_to_left of 1 means that the matched delimiter should be positioned right next to the preceding token, and left_margin of 0 removes the margin on the left. So we get:

apple;: banana::   cake
data;;  exchange:; format

You don't have to write complete names as long as they're distinguishable.

  • :EasyAlign * /[:;]\+/ { 'stl': 1, 'l': 0 }

You can even omit spaces between the arguments.

  • :EasyAlign*/[:;]\+/{'s':1,'l':0}

Nice. But let's make it even shorter. Option values can be written in shorthand notation.

  • :EasyAlign*/[:;]\+/<l0

The following table summarizes the shorthand notation.

Option Expression
filter [gv]/.*/
left_margin l[0-9]+
right_margin r[0-9]+
stick_to_left < or >
ignore_unmatched iu[01]
ignore_groups ig\[.*\]
align a[lrc*]*
delimiter_align d[lrc]
indentation i[ksdn]

Partial alignment in blockwise-visual mode

In blockwise-visual mode (CTRL-V), EasyAlign command aligns only the selected text in the block, instead of the whole lines in the range.

Consider the following case where you want to align text around => operators.

my_hash = { :a => 1,
            :aa => 2,
            :aaa => 3 }

In non-blockwise visual mode (v / V), <Enter>= won't work since the assignment operator in the first line gets in the way. So we instead enter blockwise-visual mode (CTRL-V), and select the text around => operators, then press <Enter>=.

my_hash = { :a   => 1,
            :aa  => 2,
            :aaa => 3 }

However, in this case, we don't really need blockwise visual mode since the same can be easily done using the negative N-th parameter: <Enter>-=

Alignment options

List of options

Option Type Default Description
filter string Line filtering expression: g/../ or v/../
left_margin number 1 Number of spaces to attach before delimiter
left_margin string ' ' String to attach before delimiter
right_margin number 1 Number of spaces to attach after delimiter
right_margin string ' ' String to attach after delimiter
stick_to_left boolean 0 Whether to position delimiter on the left-side
ignore_groups list ['String', 'Comment'] Delimiters in these syntax highlight groups are ignored
ignore_unmatched boolean 1 Whether to ignore lines without matching delimiter
indentation string k Indentation method (_k_eep, _d_eep, _s_hallow, _n_one)
delimiter_align string r Determines how to align delimiters of different lengths
align string l Alignment modes for multiple occurrences of delimiters

There are 4 ways to set alignment options (from lowest precedence to highest):

  1. Some option values can be set with corresponding global variables
  2. Option values can be specified in the definition of each alignment rule
  3. Option values can be given as arguments to :EasyAlign command
  4. Option values can be set in interactive mode using special shortcut keys
Option name Shortcut key Abbreviated Global variable
filter CTRL-F [gv]/.*/
left_margin CTRL-L l[0-9]+
right_margin CTRL-R r[0-9]+
stick_to_left <Left>, <Right> < or >
ignore_groups CTRL-G ig\[.*\] g:easy_align_ignore_groups
ignore_unmatched CTRL-U iu[01] g:easy_align_ignore_unmatched
indentation CTRL-I i[ksdn] g:easy_align_indentation
delimiter_align CTRL-D d[lrc] g:easy_align_delimiter_align
align CTRL-A a[lrc*]*

Filtering lines

With filter option, you can align lines that only match or do not match a given pattern. There are several ways to set the pattern.

  1. Press CTRL-F in interactive mode and type in g/pat/ or v/pat/
  2. In command-line, it can be written in dictionary format: {'filter': 'g/pat/'}
  3. Or in shorthand notation: g/pat/ or v/pat/

(You don't need to escape '/'s in the regular expression)

Examples

" Start interactive mode with filter option set to g/hello/
EasyAlign g/hello/

" Start live interactive mode with filter option set to v/goodbye/
LiveEasyAlign v/goodbye/

" Align the lines with 'hi' around the first colons
EasyAlign:g/hi/

Ignoring delimiters in comments or strings

EasyAlign can be configured to ignore delimiters in certain syntax highlight groups, such as code comments or strings. By default, delimiters that are highlighted as code comments or strings are ignored.

" Default:
"   If a delimiter is in a highlight group whose name matches
"   any of the followings, it will be ignored.
let g:easy_align_ignore_groups = ['Comment', 'String']

For example, the following paragraph

{
  # Quantity of apples: 1
  apple: 1,
  # Quantity of bananas: 2
  bananas: 2,
  # Quantity of grape:fruits: 3
  'grape:fruits': 3
}

becomes as follows on <Enter>: (or :EasyAlign:)

{
  # Quantity of apples: 1
  apple:          1,
  # Quantity of bananas: 2
  bananas:        2,
  # Quantity of grape:fruits: 3
  'grape:fruits': 3
}

Naturally, this feature only works when syntax highlighting is enabled.

You can change the default rule by using one of these 4 methods.

  1. Press CTRL-G in interactive mode to switch groups
  2. Define global g:easy_align_ignore_groups list
  3. Define a custom rule in g:easy_align_delimiters with ignore_groups option
  4. Provide ignore_groups option to :EasyAlign command. e.g. :EasyAlign:ig[]

For example if you set ignore_groups option to be an empty list, you get

{
  # Quantity of apples:  1
  apple:                 1,
  # Quantity of bananas: 2
  bananas:               2,
  # Quantity of grape:   fruits: 3
  'grape:                fruits': 3
}

If a pattern in ignore_groups is prepended by a !, it will have the opposite meaning. For instance, if ignore_groups is given as ['!Comment'], delimiters that are not highlighted as Comment will be ignored during the alignment.

Ignoring unmatched lines

ignore_unmatched option determines how EasyAlign command processes lines that do not have N-th delimiter.

  1. In left-alignment mode, they are ignored
  2. In right or center-alignment mode, they are not ignored, and the last tokens from those lines are aligned as well as if there is an invisible trailing delimiter at the end of each line
  3. If ignore_unmatched is 1, they are ignored regardless of the alignment mode
  4. If ignore_unmatched is 0, they are not ignored regardless of the mode

Let's take an example. When we align the following code block around the (1st) colons,

{
  apple: proc {
    this_line_does_not_have_a_colon
  },
  bananas: 2,
  grapefruits: 3
}

this is usually what we want.

{
  apple:       proc {
    this_line_does_not_have_a_colon
  },
  bananas:     2,
  grapefruits: 3
}

However, we can override this default behavior by setting ignore_unmatched option to zero using one of the following methods.

  1. Press CTRL-U in interactive mode to toggle ignore_unmatched option
  2. Set the global g:easy_align_ignore_unmatched variable to 0
  3. Define a custom alignment rule with ignore_unmatched option set to 0
  4. Provide ignore_unmatched option to :EasyAlign command. e.g. :EasyAlign:iu0

Then we get,

{
  apple:                             proc {
    this_line_does_not_have_a_colon
  },
  bananas:                           2,
  grapefruits:                       3
}

Aligning delimiters of different lengths

Global g:easy_align_delimiter_align option and rule-wise/command-wise delimiter_align option determines how matched delimiters of different lengths are aligned.

apple = 1
banana += apple
cake ||= banana

By default, delimiters are right-aligned as follows.

apple    = 1
banana  += apple
cake   ||= banana

However, with :EasyAlign=dl, delimiters are left-aligned.

apple  =   1
banana +=  apple
cake   ||= banana

And on :EasyAlign=dc, center-aligned.

apple   =  1
banana +=  apple
cake   ||= banana

In interactive mode, you can change the option value with CTRL-D key.

Adjusting indentation

By default :EasyAlign command keeps the original indentation of the lines. But then again we have indentation option. See the following example.

# Lines with different indentation
  apple = 1
    banana = 2
      cake = 3
        daisy = 4
     eggplant = 5

# Default: _k_eep the original indentation
#   :EasyAlign=
  apple       = 1
    banana    = 2
      cake    = 3
        daisy = 4
     eggplant = 5

# Use the _s_hallowest indentation among the lines
#   :EasyAlign=is
  apple    = 1
  banana   = 2
  cake     = 3
  daisy    = 4
  eggplant = 5

# Use the _d_eepest indentation among the lines
#   :EasyAlign=id
        apple    = 1
        banana   = 2
        cake     = 3
        daisy    = 4
        eggplant = 5

# Indentation: _n_one
#   :EasyAlign=in
apple    = 1
banana   = 2
cake     = 3
daisy    = 4
eggplant = 5

In interactive mode, you can change the option value with CTRL-I key.

Alignments over multiple occurrences of delimiters

As stated above, "N-th" parameter is used to target specific occurrences of the delimiter when it appears multiple times in each line.

To recap:

" Left-alignment around the FIRST occurrences of delimiters
:EasyAlign =

" Left-alignment around the SECOND occurrences of delimiters
:EasyAlign 2=

" Left-alignment around the LAST occurrences of delimiters
:EasyAlign -=

" Left-alignment around ALL occurrences of delimiters
:EasyAlign *=

" Left-right ALTERNATING alignment around all occurrences of delimiters
:EasyAlign **=

" Right-left ALTERNATING alignment around all occurrences of delimiters
:EasyAlign! **=

In addition to these, you can fine-tune alignments over multiple occurrences of the delimiters with 'align' option. (The option can also be set in interactive mode with the special key CTRL-A)

" Left alignment over the first two occurrences of delimiters
:EasyAlign = { 'align': 'll' }

" Right, left, center alignment over the 1st to 3rd occurrences of delimiters
:EasyAlign = { 'a': 'rlc' }

" Using shorthand notation
:EasyAlign = arlc

" Right, left, center alignment over the 2nd to 4th occurrences of delimiters
:EasyAlign 2=arlc

" (*) Repeating alignments (default: l, r, or c)
"   Right, left, center, center, center, center, ...
:EasyAlign *=arlc

" (**) Alternating alignments (default: lr or rl)
"   Right, left, center, right, left, center, ...
:EasyAlign **=arlc

" Right, left, center, center, center, ... repeating alignment
" over the 3rd to the last occurrences of delimiters
:EasyAlign 3=arlc*

" Right, left, center, right, left, center, ... alternating alignment
" over the 3rd to the last occurrences of delimiters
:EasyAlign 3=arlc**

Extending alignment rules

Although the default rules should cover the most of the use cases, you can extend the rules by setting a dictionary named g:easy_align_delimiters.

You may refer to the definitions of the default alignment rules here.

Examples

let g:easy_align_delimiters = {
\ '>': { 'pattern': '>>\|=>\|>' },
\ '/': {
\     'pattern':         '//\+\|/\*\|\*/',
\     'delimiter_align': 'l',
\     'ignore_groups':   ['!Comment'] },
\ ']': {
\     'pattern':       '[[\]]',
\     'left_margin':   0,
\     'right_margin':  0,
\     'stick_to_left': 0
\   },
\ ')': {
\     'pattern':       '[()]',
\     'left_margin':   0,
\     'right_margin':  0,
\     'stick_to_left': 0
\   },
\ 'd': {
\     'pattern':      ' \(\S\+\s*[;=]\)\@=',
\     'left_margin':  0,
\     'right_margin': 0
\   }
\ }

Other options

Disabling &foldmethod during alignment

It is reported that &foldmethod value of expr or syntax can significantly slow down the alignment when editing a large, complex file with many folds. To alleviate this issue, EasyAlign provides an option to temporarily set &foldmethod to manual during the alignment task. In order to enable this feature, set g:easy_align_bypass_fold switch to 1.

let g:easy_align_bypass_fold = 1

Left/right/center mode switch in interactive mode

In interactive mode, you can choose the alignment mode you want by pressing enter keys. The non-bang command, :EasyAlign starts in left-alignment mode and changes to right and center mode as you press enter keys, while the bang version first starts in right-alignment mode.

  • :EasyAlign
    • Left, Right, Center
  • :EasyAlign!
    • Right, Left, Center

If you do not prefer this default mode transition, you can define your own settings as follows.

let g:easy_align_interactive_modes = ['l', 'r']
let g:easy_align_bang_interactive_modes = ['c', 'r']

Advanced examples and use cases

See EXAMPLES.md for more examples.

Related work

Author

Junegunn Choi

License

MIT
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