# Helpful Vim tools for Fuchsia development

## Features

The [`fuchsia.vim`](/scripts/vim/fuchsia.vim) script sets up Vim
to do the following:

* Set paths so that `:find` and `gf` know how to find files.
* Enable FIDL syntax highlighting (using `/lib/fidl/tools/vim/`).
* Integrate basic build system so that `:make` builds and populates the
  QuickFix window.
* Configure [YouCompleteMe](/docs/development/editors/youcompleteme.md) (YCM)
  to provide error checking, code completion, and source navigation
  within the Fuchsia tree.

## Installation

The steps are:

1. [Update your login script](#update-your-login-script).
1. [Run the fx set command](#run-the-fx-set-command).
1. [Update your Vim startup file](#update-your-vim-startup-file).
1. [Restart Vim to configure YouCompleteMe](#restart-vim-to-configure-ycm).
1. [Build a compilation database](#build-a-compilation-database).

### Update your login script {:#update-your-login-script}

Add the following line to your startup script (typically `~/.bashrc`):

```shell
export FUCHSIA_DIR=<your_fuchsia_source_directory>
```

### Run the fx set command {:#run-the-fx-set-command}

This command uses the format `fx set [PRODUCT].[BOARD]`. For example:

```shell
fx set core.x64
```

### Update your Vim startup file {:#update-your-vim-startup-file}

If the following line exists in your `~/.vimrc` file, remove it:

```shell
filetype plugin indent on
```

Then add the following lines to your `~/.vimrc`:

```shell
if $FUCHSIA_DIR != ""
  source $FUCHSIA_DIR/scripts/vim/fuchsia.vim
endif
filetype plugin indent on
```

### Restart Vim to configure YouCompleteMe {:#restart-vim-to-configure-ycm}

Note: If you haven't installed YouCompleteMe,
see [this installation guide] (https://github.com/ycm-core/YouCompleteMe#installation){:.external}
to install YCM on your workstation.

To configure YouCompleteMe (YCM), you need to source the
[`fuchsia.vim`](/scripts/vim/fuchsia.vim) file.

Restart your Vim to run the
`source $FUCHSIA_DIR/scripts/vim/fuchsia.vim` command in your `~/.vimrc`
file (see [Update your Vim startup file](#update-yout-vim-startup-file)).

To verify that your YCM works, place the cursor on an
identifier in a `.cc` or `.h` file in Vim, then hit `Ctrl+]`
to navigate to the definition of the identifier.

### Build a compilation database {:#build-a-compilation-database}

YCM uses the
[compilation database](https://github.com/ycm-core/YouCompleteMe#option-1-use-a-compilation-database){:.external},
which is more reliable and efficient than the default
[`ycm_extra_config.py` configuration](/docs/development/editors/youcompleteme.md#generate_compilation_database).

To build a compilation database, run the following command:

```shell
fx compdb
```