1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
# Using Helix
<!--toc:start-->
- [Registers](#registers)
- [User-defined registers](#user-defined-registers)
- [Special registers](#special-registers)
- [Surround](#surround)
- [Selecting and manipulating text with textobjects](#selecting-and-manipulating-text-with-textobjects)
- [Navigating using tree-sitter textobjects](#navigating-using-tree-sitter-textobjects)
- [Moving the selection with syntax-aware motions](#moving-the-selection-with-syntax-aware-motions)
<!--toc:end-->
For a full interactive introduction to Helix, refer to the
[tutor](https://github.com/helix-editor/helix/blob/master/runtime/tutor) which
can be accessed via the command `hx --tutor` or `:tutor`.
> π‘ Currently, not all functionality is fully documented, please refer to the
> [key mappings](./keymap.md) list.
## Registers
In Helix, registers are storage locations for text and other data, such as the
result of a search. Registers can be used to cut, copy, and paste text, similar
to the clipboard in other text editors. Usage is similar to Vim, with `"` being
used to select a register.
### User-defined registers
Helix allows you to create your own named registers for storing text, for
example:
- `"ay` - Yank the current selection to register `a`.
- `"op` - Paste the text in register `o` after the selection.
If a register is selected before invoking a change or delete command, the selection will be stored in the register and the action will be carried out:
- `"hc` - Store the selection in register `h` and then change it (delete and enter insert mode).
- `"md` - Store the selection in register `m` and delete it.
### Default registers
Commands that use registers, like yank (`y`), use a default register if none is specified.
These registers are used as defaults:
| Register character | Contains |
| --- | --- |
| `/` | Last search |
| `:` | Last executed command |
| `"` | Last yanked text |
| `@` | Last recorded macro |
### Special registers
Some registers have special behavior when read from and written to.
| Register character | When read | When written |
| --- | --- | --- |
| `_` | No values are returned | All values are discarded |
| `#` | Selection indices (first selection is `1`, second is `2`, etc.) | This register is not writable |
| `.` | Contents of the current selections | This register is not writable |
| `%` | Name of the current file | This register is not writable |
| `+` | Reads from the system clipboard | Joins and yanks to the system clipboard |
| `*` | Reads from the primary clipboard | Joins and yanks to the primary clipboard |
When yanking multiple selections to the clipboard registers, the selections
are joined with newlines. Pasting from these registers will paste multiple
selections if the clipboard was last yanked to by the Helix session. Otherwise
the clipboard contents are pasted as one selection.
## Surround
Helix includes built-in functionality similar to [vim-surround](https://github.com/tpope/vim-surround).
The keymappings have been inspired from [vim-sandwich](https://github.com/machakann/vim-sandwich):
| Key Sequence | Action |
| --------------------------------- | --------------------------------------- |
| `ms<char>` (after selecting text) | Add surround characters to selection |
| `mr<char_to_replace><new_char>` | Replace the closest surround characters |
| `md<char_to_delete>` | Delete the closest surround characters |
You can use counts to act on outer pairs.
Surround can also act on multiple selections. For example, to change every occurrence of `(use)` to `[use]`:
1. `%` to select the whole file
2. `s` to split the selections on a search term
3. Input `use` and hit Enter
4. `mr([` to replace the parentheses with square brackets
Multiple characters are currently not supported, but planned for future release.
## Selecting and manipulating text with textobjects
In Helix, textobjects are a way to select, manipulate and operate on a piece of
text in a structured way. They allow you to refer to blocks of text based on
their structure or purpose, such as a word, sentence, paragraph, or even a
function or block of code.
- `ma` - Select around the object (`va` in Vim, `<alt-a>` in Kakoune)
- `mi` - Select inside the object (`vi` in Vim, `<alt-i>` in Kakoune)
| Key after `mi` or `ma` | Textobject selected |
| --- | --- |
| `w` | Word |
| `W` | WORD |
| `p` | Paragraph |
| `(`, `[`, `'`, etc. | Specified surround pairs |
| `m` | The closest surround pair |
| `f` | Function |
| `t` | Type (or Class) |
| `a` | Argument/parameter |
| `c` | Comment |
| `T` | Test |
| `g` | Change |
> π‘ `f`, `t`, etc. need a tree-sitter grammar active for the current
document and a special tree-sitter query file to work properly. [Only
some grammars][lang-support] currently have the query file implemented.
Contributions are welcome!
## Navigating using tree-sitter textobjects
Navigating between functions, classes, parameters, and other elements is
possible using tree-sitter and textobject queries. For
example to move to the next function use `]f`, to move to previous
type use `[t`, and so on.
![Tree-sitter-nav-demo][tree-sitter-nav-demo]
For the full reference see the [unimpaired][unimpaired-keybinds] section of the key bind
documentation.
> π‘ This feature relies on tree-sitter textobjects
> and requires the corresponding query file to work properly.
## Moving the selection with syntax-aware motions
`Alt-p`, `Alt-o`, `Alt-i`, and `Alt-n` (or `Alt` and arrow keys) allow you to move the
selection according to its location in the syntax tree. For example, many languages have the
following syntax for function calls:
```js
func(arg1, arg2, arg3);
```
A function call might be parsed by tree-sitter into a tree like the following.
```tsq
(call
function: (identifier) ; func
arguments:
(arguments ; (arg1, arg2, arg3)
(identifier) ; arg1
(identifier) ; arg2
(identifier))) ; arg3
```
Use `:tree-sitter-subtree` to view the syntax tree of the primary selection. In
a more intuitive tree format:
```
ββββββ
βcallβ
βββββββ΄βββββ΄ββββββ
β β
βββββββΌβββββ ββββββΌβββββ
βidentifierβ βargumentsβ
β "func" β ββββββ΄ββββ¬ββββββ΄ββββ
ββββββββββββ β β β
β β β
βββββββββββΌβ ββββββΌββββββ ββΌββββββββββ
βidentifierβ βidentifierβ βidentifierβ
β "arg1" β β "arg2" β β "arg3" β
ββββββββββββ ββββββββββββ ββββββββββββ
```
If you have a selection that wraps `arg1` (see the tree above), and you use
`Alt-n`, it will select the next sibling in the syntax tree: `arg2`.
```js
// before
func([arg1], arg2, arg3)
// after
func(arg1, [arg2], arg3);
```
Similarly, `Alt-o` will expand the selection to the parent node, in this case, the
arguments node.
```js
func[(arg1, arg2, arg3)];
```
There is also some nuanced behavior that prevents you from getting stuck on a
node with no sibling. When using `Alt-p` with a selection on `arg1`, the previous
child node will be selected. In the event that `arg1` does not have a previous
sibling, the selection will move up the syntax tree and select the previous
element. As a result, using `Alt-p` with a selection on `arg1` will move the
selection to the "func" `identifier`.
[lang-support]: ./lang-support.md
[unimpaired-keybinds]: ./keymap.md#unimpaired
[tree-sitter-nav-demo]: https://user-images.githubusercontent.com/23398472/152332550-7dfff043-36a2-4aec-b8f2-77c13eb56d6f.gif
|
