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Yasnippets

The Emacs snippet manager

Where there are many packages to manage snippets in emacs, yasnippets is by far the most complete and robust solution. With robustness and completeness, unfortunately, also comes weight, and for this reason there are many other snippet managers that one might prefer. Although, to our knowledge, none of these other snippet managers come with the option to install quite a generous collection of premade snippets.

Installation

As with all packages in our Emacs configuration, package installation is performed using straight.el integrated with the famous use-package.el package configuration system. Using this, all one needs to do is simply add the below block of code to your emacs configuration file.

(use-package yasnippet)

and your done.

Writing snippets

Yasnippets has it’s own file format and mode for handling said format. Creation of snippets can be done by executing the command yas-new-snippet or C-c C-n on the keyboard. If you go this route, when finished, all one needs to do is hit C-x C-s and a dialogue will ask you what mode is the snippet for, and then will ask for confirmation of the location to save the file. Snippets are generally stored in the ~/.emacs.d/snippets/ and inside a folder with the same name as the mode for which the snippet is for. Once finished, simply press enter.

If one does not desire to use the automated method of creating snippets, they can do so manually as long as they follow the correct file format. All yasnippets start with the same header:

# -*- mode: snippet -*-
# name: snippet_name
# key: some_key
# --

;; Here is where you write your snippet.

Once written, simply save the file in the propert location and tell yasnippet to reload all snippets.

Autobinding keys to snippets

A cool feature of yasnippet is it’s ability to automatically add keybinds directly to the insertion of snippets simply by adding them to the snippet file after the heading label binding:. Nothing else is needed after the label, which makes this step really convenient. To take the example provided above, adding a binding label would change our heading to below.

# -*- mode: snippet -*-
# name: snippet_name
# key: some_key
# binding: C-c C-z x
# --

;; Here is where you write your snippet.

This would allow us to insert the snippet simply by pressing Ctrl-c Ctrl-z x keys. Super cool.

Adding place holders to your snippets.

If a snippet contains a placeholder, then once the snippet is inserted into the file, the cursor will automatically moved to the first placeholder, and the placeholder label will be highlighted. You can then directly type in the replacement text for the placeholder label, and that text will overwrite the placeholder label. To move to the next placeholder, simply use Tab and the cursor will jumpt to the next placeholder in the order which the snippet was written.

Placeholders with labels can be added to your snippets by use of the format ${N:LABEL}. Where N is the number designating the order in which the labels should be replaced, and LABEL is the actually placeholder label that will be replaced by the user. ¹ A basic example is provided below:

# -*- mode: snippet -*-
# name: she_bang
# key: some_key
# --
#!/usr/bin/env ${1:Shell}

When you insert this snippet it the fifth hash mark will be read exactly as you intended it, and the cursor will be moved automatically to the shell placeholder for you to designate your shell.

Using Elisp in your snippets

Once you understand how to create placeholders inside your snippet files, it will be very easy to pick up on how to include elisp in your snippet files as well. The only difference between the two, is instead of writing your placeholder label after your numeric designator ², you would write your elisp code inside of a pair of backticks “(CODE)”. For example:

${1:Label}

;; would be

${1:`(some elisp code here)`}

If you have not yet, you should visit yasnippets documentation. It is written very well, and to the point. (Unlike this wiki.)