auto-yasnippet

https://github.com/abo-abo/auto-yasnippet.git

git clone 'git://github.com/abo-abo/auto-yasnippet.git'


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Auto-YASnippet

This is a hybrid of keyboard macro and yasnippet. You create the snippet on the go, usually to be used just in the one place. It's fast, because you're not leaving the current buffer, and all you do is enter the code you'd enter anyway, just placing ~ where you'd like yasnippet fields and mirrors to be.

Functions

aya-create

Removes “~” from current line or region (if mark is active) yielding valid code. The created snippet is recorded into aya-current.

aya-expand

Expands whatever is currently in aya-current

aya-open-line

Generic expansion function. It will either expand or move to the next field depending on the context.

aya-persist-snippet

Save the current auto-snippet to a user snippets folder (this defaults to ~/.emacs.d/snippets/.) The current major-mode name will be used to determine the snippets sub-directory to store the snippet. For example when working in js2-mode the snippet will be saved to (by default) ~/.emacs.d/snippets/js2-mode/.

You will be prompted for the snippet name. The appropriate file will be opened but not saved, with the point on the key: parameter of the snippet. If you wish to proceed, fill in the key, save the buffer and call C-c C-l (yas-load-snippet-buffer). Otherwise, simply kill the buffer - there will be no side effects.

You can customize aya-persist-snippets-dir to use a different folder for storing auto-snippets.

You will need to run yas/reload-all before using the new snippet with it's key trigger.

Installation instructions

It's easiest/recommended to install from MELPA. Here's a minimal MELPA configuration for your ~/.emacs:

(package-initialize)
(add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/"))

Afterwards, M-x package-install RET auto-yasnippet RET (you might want to M-x package-refresh-contents RET beforehand if you haven't done so recently).

You will also want to setup the key bindings. Here's what I recommend:

(global-set-key (kbd "H-w") 'aya-create)
(global-set-key (kbd "H-y") 'aya-expand)

I also like to bind this, instead of using TAB to expand yasnippets:

(global-set-key (kbd "C-o") 'aya-open-line)

Usage examples

JavaScript

field~1 = document.getElementById("field~1");

Since this just one line, just call aya-create (from anywhere on this line). The ~ chars disappear, yielding valid code.

aya-current becomes:

"field$1 = document.getElementById(\"field$1\");"

Now by calling aya-expand multiple times, you get:

field1 = document.getElementById("field1");
field2 = document.getElementById("field2");
field3 = document.getElementById("field3");
fieldFinal = document.getElementById("fieldFinal");

Java

class Light~On implements Runnable {
  public Light~On() {}
  public void run() {
    System.out.println("Turning ~on lights");
    light = ~true;
  }
}

This differs from the code that you wanted to write only by 4 ~ chars. Since it's more than one line, select the region and call aya-create. Again, the ~ chars disappear, yielding valid code.

aya-current becomes:

"class Light$1 implements Runnable {
  public Light$1() {}
  public void run() {
    System.out.println(\"Turning $2 lights\");
    light = $3;
  }
}"

Now by calling aya-expand, you can quickly fill in:

class LightOff implements Runnable {
  public LightOff() {}
  public void run() {
    System.out.println("Turning off lights");
    light = false;
  }
}

C++

const Point<3> curl(grad[~2][~1] - grad[~1][~2],

Select the region between the paren and the comma and call aya-create. You can easily obtain the final code:

const Point<3> curl(grad[2][1] - grad[1][2],
                    grad[0][2] - grad[2][0],
                    grad[1][0] - grad[0][1]);

Note how annoying it would be to triple check that the indices match. Now you just have to check for one line.

JavaScript - aya-one-line:

aya-one-line works as a combination of aya-create and aya-expand for one-line snippets. It's invoked by aya-create in case there's no aya-marker (default ~) on the line, but there's aya-marker-one-line (default $). Or you can invoke it on its own.

field$ = document.getElementById("");

call aya-create and the rest is as before:

field1 = document.getElementById("field1");
field2 = document.getElementById("field2");
field3 = document.getElementById("field3");
fieldFinal = document.getElementById("fieldFinal");

Generating comments

Here's a yasnippet that makes use of aya-tab-position. You need to call aya-open-line if you want to use it.

# -*- mode: snippet -*-
# name: short comment
# key: sc
# --
//———$1${1:$(make-string (- 47 aya-tab-position (length yas-text)) ?—)}$0

Comments generated with this will always end in same column position, no matter from which indentation level they were invoked from.