En capítulos anteriores, he mencionado que Vim busca de manera automática rutas especiales como `pack/` (capítulo 22) o `compiler/` (capítulo 19) dentro del directorio `~/.vim/`. Estos son ejemplos de rutas de ejecutables de Vim.
Vim tiene más rutas de ejecutables que estas dos que he mencionado, repasaremos una descripción general de alto nivel de estas rutas de ejecutables. La meta de este capítulo es mostrar cuando son llamados. Sabiendo esto, te permitirá entender y personalizar ún mas.
En equipos con Unix o derivadas, una de tus rutas de ejecutables es `$HOME/.vim/` (si tienes un sistema operativo diferente como Windows, esto podría ser diferente). Para ver qué rutas diferentes de ejecutables hay para distintos sistemas operativos, echa un vistazo a `:h 'runtimepath'`. En este capítulo, usaré `~/.vim/` como ruta predeterminada.
Vim tiene una ruta de ejecutable para los complementos que ejecutan cualquier *script* en este directorio una vez que arranca Vim. No hay que confundir el nombre "complemento" (o *plugin*) con los complementos externos de Vim (como NERDTree, fzf.vim, etc).
Ahora cierra Vim. La próxima vez que lo inicies, verás que se muestran las palabras `"donut!"` y `"chocolate!"`. La ruta de ejecutable de complemento puede ser utilizada para *scripts* de inicialización.
Cuando abre un archivo nuevo, Vim normalmente sabe qué clase de archivo es. Si tienes un archivo `hola.rb`, al ejecutar `:set filetype?` debería mostrar la respuesta correcta `filetype=ruby`.
Vim sabe cómo detectar los tipos de archivos "más comunes" (Ruby, Python, Javascript, etc). Pero ¿qué pasa si tienes un tipo de archivos personalizados? Necesitas enseñar a Vim a detectarlo y asignarlo con el tipo de archivo correcto.
File name detection detects a file type using the name of that file. When you open the `hello.rb` file, Vim knows it is a Ruby file from the `.rb` extension.
There are two ways you can do file name detection: using `ftdetect/` runtime directory and using `filetype.vim` runtime file. Let's explore both.
Let's create an obscure (yet tasty) file, `hello.chocodonut`. When you open it and you run `:set filetype?`, since it is not a common file name extension Vim doesn't know what to make of it. It returns `filetype=`.
You need to instruct Vim to set all files ending with `.chocodonut` as a "chocodonut" file type. Create a directory named `ftdetect/` in the runtime root (`~/.vim/`). Inside, create a file and name it `chocodonut.vim` (`~/.vim/ftdetect/chocodonut.vim`). Inside this file, add:
`BufNewFile` and `BufRead` are triggered whenever you create a new buffer and open a new buffer. `*.chocodonut` means that this event will only be triggered if the opened buffer has a `.chocodonut` filename extension. Finally, `set filetype=chocodonut` command sets the file type to be a chocodonut type.
Scrumptious! You can put as many files as you want inside `ftdetect/`. In the future, you can maybe add `ftdetect/strawberrydonut.vim`, `ftdetect/plaindonut.vim`, etc., if you ever decide to expand your donut file types.
There are actually two ways to set a file type in Vim. One is what you just used `set filetype=chocodonut`. The other way is to run `setfiletype chocodonut`. The former command `set filetype=chocodonut` will *always* set the file type to chocodonut type, while the latter command `setfiletype chocodonut` will only set the file type if no file type was set yet.
Create a `hello.plaindonut` file. When you open it and run `:set filetype?`, Vim displays the correct custom file type `filetype=plaindonut`.
Holy pastry, it works! By the way, if you play around with `filetype.vim`, you may notice that this file is being run multiple times when you open `hello.plaindonut`. To prevent this, you can add a guard so the main script is run only once. Update the `filetype.vim`:
`finish` is a Vim command to stop running the rest of the script. The `"did_load_filetypes"` expression is *not* a built-in Vim function. It is actually a global variable from inside `$VIMRUNTIME/filetype.vim`. If you're curious, run `:e $VIMRUNTIME/filetype.vim`. You will find these lines inside:
When Vim calls this file, it defines `did_load_filetypes` variable and sets is to 1. 1 is truthy in Vim. You should read the rest of the `filetype.vim` too. See if you can understand what it does when Vim calls it.
Suppose you have a collection of files without an agreeable extension. The only thing these files have in common is that they all start with the word "donutify" on the first line. You want to assign these files to a `donut` file type. Create new files named `sugardonut`, `glazeddonut`, and `frieddonut` (without extension). Inside each file, add this line:
The function `getline(1)` returns the text on the first line. It checks if the first line starts with the word "donutify". The function `did_filetype()` is a Vim built-in function. It will return true when a file type related event is triggered at least once. It is used as a guard to stop re-running file type event.
Open the `sugardonut` file and run `:set filetype?`, Vim now returns `filetype=donut`. If you open another donut files (`glazeddonut` and `frieddonut`), Vim also identifies their file types as `donut` types.
Note that `scripts.vim` is only run when Vim opens a file with an unknown file type. If Vim opens a file with a known file type, `scripts.vim` won't run.
You can do this with file type plugin runtime path (`~/.vim/ftplugin/`). Vim looks inside this directory for a file with the same name as the file type you just opened. Create a `chocodonut.vim` (`~/.vim/ftplugin/chocodonut.vim`):
Create another ftplugin file, `plaindonut.vim` (`~/.vim/ftplugin/plaindonut.vim`):
```
echo "Calling from plaindonut ftplugin"
```
Now each time you open a chocodonut file type, Vim runs the scripts from `~/.vim/ftplugin/chocodonut.vim`. Each time you open a plaindonut file type, Vim runs the scripts from `~/.vim/ftplugin/plaindonut.vim`.
One warning: these files are run each time a buffer file type is set (`set filetype=chocodonut` for example). If you open 3 different chocodonut files, the scripts will be run a *total* of three times.
Vim has an indent runtime path that works similar to ftplugin, where Vim looks for a file named the same as the opened file type. The purpose of these indent runtime paths is to store indent-related codes. If you the file `~/.vim/indent/chocodonut.vim`, it will be executed only when you open a chocodonut file type. You can store indent-related codes for chocodonut files here.
Vim has a colors runtime path (`~/.vim/colors/`) to store color schemes. Any file that goes inside the directory will be displayed in the `:color` command-line command.
If you have a `~/.vim/colors/beautifulprettycolors.vim` file, when you run `:color` and press tab, you will see `beautifulprettycolors` as one of the color options. If you prefer to add your own color scheme, this is the place to go.
Although Vim now knows the correct file type, all texts have the same color. Let's add a syntax highlighting rule to highlight the "donut" keyword. Create a new chocodonut syntax file, `~/.vim/syntax/chocodonut.vim`. Inside it add:
Now reopen `hello.chocodonut` file. The `donut` keywords are now highlighted.
This chapter won't go over syntax highlighting in depth. It is a vast topic. If you are curious, check out `:h syntax.txt`.
The [vim-polyglot](https://github.com/sheerun/vim-polyglot) plugin is a great plugin that provides highlights for many popular programming languages.
## Documentation
If you create a plugin, you will have to create your own documentation. You use the doc runtime path for that.
Let's create a basic documentation for chocodonut and plaindonut keywords. Create a `donut.txt` (`~/.vim/doc/donut.txt`). Inside, add these texts:
```
*chocodonut* Delicious chocolate donut
*plaindonut* No choco goodness but still delicious nonetheless
```
If you try to search for `chocodonut` and `plaindonut` (`:h chocodonut` and `:h plaindonut`), you won't find anything.
First, you need to run `:helptags` to generate new help entries. Run `:helptags ~/.vim/doc/`
Now if you run `:h chocodonut` and `:h plaindonut`, you will find these new help entries. Notice that the file is now read-only and has a "help" file type.
All of the runtime paths that you learned in this chapter were run automatically. If you want to manually load a script, use the autoload runtime path.
Create an autoload directory (`~/.vim/autoload/`). Inside that directory, create a new file and name it `tasty.vim` (`~/.vim/autoload/tasty.vim`). Inside it:
Note that the function name is `tasty#donut`, not `donut()`. The pound sign (`#`) is required when using the autoload feature. The function naming convention for the autoload feature is:
The first time you call the function, you should see *both* echo messages ("tasty.vim global" and "tasty#donut"). The subsequent calls to` tasty#donut` function will only display "testy#donut" echo.
When you open a file in Vim, unlike the previous runtime paths, autoload scripts aren't loaded automatically. Only when you explicitly call `tasty#donut()`, Vim looks for the `tasty.vim` file and loads everything inside it, including the `tasty#donut()` function. Autoload is the perfect mechanism for functions that use extensive resources but you don't use often.
You can add as many nested directories with autoload as you want. If you have the runtime path `~/.vim/autoload/one/two/three/tasty.vim`, you can call the function with `:call one#two#three#tasty#donut()`.
Vim has an after runtime path (`~/.vim/after/`) that mirrors the structure of `~/.vim/`. Anything in this path is executed last, so developers usually use these paths for script overrides.
For example, if you want to overwrite the scripts from `plugin/chocolate.vim`, you can create `~/.vim/after/plugin/chocolate.vim` to put the override scripts. Vim will run the `~/.vim/after/plugin/chocolate.vim`*after*`~/.vim/plugin/chocolate.vim`.
## $VIMRUNTIME
Vim has an environment variable `$VIMRUNTIME` for default scripts and support files. You can check it out by running `:e $VIMRUNTIME`.
The structure should look familiar. It contains many runtime paths you learned in this chapter.
Recall in Chapter 21, you learned that when you open Vim, it looks for a vimrc files in seven different locations. I said that the last location Vim checks is `$VIMRUNTIME/default.vim`. If Vim fails to find any uservimrc files, Vim uses a `default.vim` as vimrc.
Have you ever tried running Vim without syntax plugin like vim-polyglot and yet your file is still syntatically highlighted? That is because when Vim fails to find a syntax file from the runtime path, Vim looks for a syntax file from `$VIMRUNTIME` syntax directory.
One of the things plugin managers does is adding each plugin into the runtime path. Each runtime path can have its own directory structure similar to `~/.vim/`.
If you have a directory `~/box/of/donuts/` and you want to add that directory to your runtime path, you can add this to your vimrc:
If inside `~/box/of/donuts/`, you have a plugin directory (`~/box/of/donuts/plugin/hello.vim`) and a ftplugin (`~/box/of/donuts/ftplugin/chocodonut.vim`), Vim will run all scripts from `plugin/hello.vim` when you open Vim. Vim will also run `ftplugin/chocodonut.vim` when you open a chocodonut file.
Try this yourself: create an arbitrary path and add it to your runtimepath. Add some of the runtime paths you learned from this chapter. Make sure they work as expected.
Take your time reading it and play around with these runtime paths. To see how runtime paths are being used in the wild, go to the repository of one of your favorite Vim plugins and study its directory structure. You should be able to understand most of them now. Try to follow along and discern the big picture. Now that you understand Vim directory structure, you're ready to learn Vimscript.
