Auto-YASnippet 1.0.0

Auto-YASnippet is a hybrid of keyboard macros and YASnippet. You create the snippet on the go and it'll be ready to use immediately. Because you're not leaving the current buffer the workflow is very fast.

All you do is enter the code you'd enter anyway but placing ~ chars where you`d like YASnippet fields and mirrors to be.

Table of Contents

• Auto-YASnippet 1.0.0
• Setup/Install
• Configuration
• Examples
  • Multiple placeholders
  • Mixed case templates
  • Expanding around a region
• Functions
  • aya-create
  • aya-expand
  • aya-expand-from-history
  • aya-delete-from-history
  • aya-next-in-history & aya-previous-in-history
  • aya-open-line
  • aya-persist-snippet
  • aya-persist-snippet-from-history

Setup/Install

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).

Configuration

In your Emacs init file set keys for the aya commands.

For example:

(global-set-key (kbd "C-c C-y w")   #'aya-create)
(global-set-key (kbd "C-c C-y TAB") #'aya-expand)
(global-set-key (kbd "C-c C-y SPC") #'aya-expand-from-history)
(global-set-key (kbd "C-c C-y d")   #'aya-delete-from-history)
(global-set-key (kbd "C-c C-y c")   #'aya-clear-history)
(global-set-key (kbd "C-c C-y n")   #'aya-next-in-history)
(global-set-key (kbd "C-c C-y p")   #'aya-previous-in-history)
(global-set-key (kbd "C-c C-y s")   #'aya-persist-snippet)
(global-set-key (kbd "C-c C-y o")   #'aya-open-line)

Examples

If we need to write some repetitive code in an expression:

count_of_red = get_total("red");
count_of_blue = get_total("blue");
count_of_green = get_total("green");

We can write a template, using ~ to represent text we want to replace:

count_of_~red = get_total("~red");

With the cursor on this line, or with selected text, call M-x aya-create RET. An auto-snippet is created and the text is converted to remove the ~ marker:

count_of_red = get_total("red");

Now we can call aya-expand and we can insert text at each marker in the template, note, because both words are the same, we just type it one.

Yasnippet controls all the interaction while expanding so refer to the yasnippet docs. Basic interaction is to enter text at a marker and TAB to the next one.

count_of_[CURSOR] = get_total("");

Say we enter blue once at `count_of_`` the result will be.

count_of_blue = get_total("blue");

Multiple placeholders

You can replace multiple values in a template, just like normal yasnippet.

In this example, our template has multiple lines, so we need to select the relevant lines before calling aya-create

~FooType get~Foo() {
    // Get the ~foo attribute on this.
    return this.~foo;
}

We fill in two placeholders in this example (the 2nd and 4th are the same as the 3rd). Yasnippet places us at 1st, entering: Type TAB (yasnippet puts us at 3rd) entering: bar TAB will expand to:

Type getBar() {
  // Get the bar attribute on this.
  return this.foo;
}

Mixed case templates

You can create mixed case templates setting aya-case-fold to t. This will result in templates where variables that start with a character of a different case will be treated as the same variable. The case of the first character will be preserved in the resulting snippet.

Using the earlier example with a slight twist:

count_of_~red = get_total("~Red");

Then calling aya-create, then aya-expand, and finally typing blue, the result would be:

count_of_blue = get_total("Blue");

Notice that blue was placed in both locations with proper casing.

Expanding around a region

If you create an auto-yasnippet with one field, it's value will be filled in from the current region. For example if we create a new snippet:

print("\(~thing)")

Select text:

myVar + 10

aya-expand gives us...

print("\(myVar + 10)")

You can also use the YASnippet built in marker $0 in the point where you want to finish expanding the snippet. YASnippet allows $0 to be the region, by setting yas-wrap-around-region to t.

Functions

aya-create

Removes "~" from current line or region (if mark is active) yielding valid code. The created snippet is recorded into aya-current and appended to aya-history.

aya-expand

Expands whatever is currently in aya-current

aya-expand-from-history

Select and expand from snippets in aya-history. The selected snippet will become aya-current.

aya-delete-from-history

Select and delete a snippet from aya-history. The next available snippet will become aya-current. When there are no other snippets available aya-current will be set to "".

aya-next-in-history & aya-previous-in-history

Set aya-current to the next or previous in aya-history.

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 its key trigger.

aya-persist-snippet-from-history

Functionally equivalent to aya-persist-snippet but using a snippet selected from aya-history