---
.title = "Commands",
.date = @date("2025-10-15T00:00:00"),
.author = "Igor Támara",
.layout = "tutorial.shtml",
.draft = false,
.custom = { .githubedit = "https://github.com/neurocyte/flow-website/tree/master/content/docs/architecture/command.md"},
---

Commands are actions triggered to operate on buffers primarily. They
are present in `editor`, `tui`, `mode` and `minimodes`, it's possible
to find commands in other places, which will become evident when the
need arises.

## Previous notes

Note: Flow is programmed with [zig](https://ziglang.org/), if you are familiar
with C, C++, Rust, there are differences and reasonings that
might find useful when [learning Zig](https://ziglang.org/learn/). If you
are coming from higher level programming languages such as Python, Ruby,
C#, Java, Golang, Typescript it will be an opportunity to learn about trades
of managing memory and fast responses and some lower level concepts present
in Zig. If you are brand new to programming, some general concepts will be
needed and practice in another language before getting into flow development.

If you are new to Zig, it's a good idea to take a look at
[ziglings](https://ziglings.org/) to practice, as you learn the language.

Maybe there is a [shell command invoked](/docs/architecture/keybind#shell) with a
keybinding that can help in the task you are aiming at before developing
flow itself.

## Understanding and creating commands

A command is a function with a type like

```zig
pub fn copy(self: *Self, _: Context) Result
```

and a `Meta` definition with the same name and suffix `_meta`.

```zig
pub const copy_meta: Meta = .{ .description = "Copy selection to clipboard" };
```

`copy` command is defined in `editor.zig`, which copies the current
selections into the pimp internal clipboard. Commands are available
to all the modes if defined as pub.

`meta` holds the description appearing in the command palette and optionally
has arguments, the most common, an integer, that usually constitutes a
repetition parameter, targeting vim, emacs and helix modes. As you dig in,
there might be particularities on the parameters accepted for a given
command.

## Invoking another command

Commands can be bound to mnemonics in modes by convention. For example, in
Vim Mode `vim.zig`, `q` corresponds to (quit), the most famous one.

```zig
pub fn q(_: *void, _: Ctx) Result {
    try cmd("quit", .{});
}
pub const q_meta: Meta = .{ .description = "q (quit)" };
```

Looking more closely, the first parameter in this case is of `*void` type,
given that this command is defined in `vim.zig` which is calling the `quit`
command defined in `editor.zig`. `cmd` takes care of routing and finding
the command wherever it is defined.

## Chaining commands

Chaining commands is also common, and, by the way, swift. This is a sample
of applying first `save_file` command and then, the command `quit`.

```zig
pub fn wq(_: *void, _: Ctx) Result {
    try cmd("save_file", command.fmt(.{ "then", .{ "quit", .{} } }));
}
pub const wq_meta: Meta = .{ .description = "wq (write file and quit)" };
```

Sometimes [keybinding](/docs/architecture/keybind) is enough to accomplish
a compound of already present commands, in others, zig programming is the
path to be taken.

# More in depth commands

Is common to define private functions in a given module that are invoked from
commands, as usual, functions are meant to be reused and help organize code.

For example, in hx mode `helix.zig` the `select_to_char_left_helix` command
uses the functions `helix_with_selections_const_arg` which iterates over all
cursels and applies the `select_cursel_to_char_left_helix` function.

```zig
pub fn select_to_char_left_helix(_: *void, ctx: Ctx) Result {
    try helix_with_selections_const_arg(ctx, &select_cursel_to_char_left_helix);
}
```

## Sending parameters to commands

`cmd` is in charge of finding a command given its name, and parameters sent
to commands are vary for each command, for example, when interacting with
the clipboard, the messages sent are multiple chunks of information, for
now an example of such usage can be seen in a function that fetches contents
from the clipboard.



There are more advanced topics related to commands that are covered in the
[editor](/docs/architecture/editor), that deeps in specific details of
the editor and its interaction with cursors, selections and buffers
modifications, among others.

Learning about interactions with the buffer and editor is present in
[minimodes](/docs/architecture/minimode).