Para

Work in progress. Not usable right now.

This package allows to deal with pairs efficiently. It provides the following:

• Functions for navigation in and manipulation of S-expressions. These include:

  • para-beginning-of-sexp
  • para-end-of-sexp
  • para-down-sexp
  • para-up-sexp
  • para-backward-down-sexp
  • para-backward-up-sexp
  • para-forward-sexp
  • para-backward-sexp
  • para-next-sexp
  • para-previous-sexp
  • para-backward-unwrap-sexp
  • para-unwrap-sexp
  • para-forward-slurp-sexp
  • para-forward-barf-sexp
  • para-backward-slurp-sexp
  • para-backward-barf-sexp
  • para-transpose-sexp
  • para-kill-sexp
  • para-backward-kill-sexp
  • para-kill-hybrid-sexp
  • para-select-next-sexp
  • para-select-previous-sexp

• Automatic insertion of closing pair. Para does not skip closing pair if it already exists, it inserts closing pair if you press key corresponding to it. It's easy to get into the habit of moving cursor one character forward instead of trying to insert already inserted character. This feature makes the package stateless, this is one of aims of this project.

• Automatic deletion of complete pairs. If cursor is placed behind whole pair and you press backspace, closing pair is deleted, as usual. If cursor is between paired characters and there is no text between them, only in that case deleting of opening pair will delete the closing pair as well. Otherwise opening pair is deleted as usual.

• Wrapping of active region. If you have active region and enter paired character the region is wrapped. Due to certain confusion that this feature can lead to (if you prefer to delete selected text when new text is typed), only single-character pairs work this way.

• Some pairs, like simple single quote which often serves as apostrophe and can be part of identifiers in some languages (Haskell), are handled intelligently. When it can be part of word or identifier it's not automatically paired. You can give this behavior to other pairs, since the package is quite flexible, but default configuration should be OK in most cases.

• The package can work with multi-character pairs and pairs where opening and closing sequences are identical.

However, Para is not a clone of Smartparens. It's much more clean, minimalistic, and fast. In my opinion packages for basic editing should be simple, robust, and they should not ever let you down. To achieve these goals Para adheres to the following principles:

• No state in your editing. Every combination of user's actions always result in the same thing no matter what manipulations user performed before it.

• No useless flashy things. Overlays in basic editing? I don't get it.

• Clear API for users. To define a pair you need to specify exactly two things: opening pair and closing pair. You can specify when this pair will be active too, but it's a different thing.

• Clean design from the very beginning and a lot of tests covering everything.

• Does not increase typing latency. Some packages use hooks that are executed after every key press and put heavy code there, and then it sums up and you get laggy text editor. It can get slower than IDE — certainly we can do better.

What's wrong with Smartparens?

I was user of Smartparens for about two years. Never liked it because of its technical debt and overlays, but couldn't find decent replacement.

I really tried several times to avoid writing this (para) package. I suspended development several times thinking that Smartpares is getting better. However, recently I had very annoying problems with typing latency that frustrated me to the point that I was close to switch to Atom text editor after years of Emacs. I tracked the latency problem down to two main sources of delay: Flyspell and Smartparens. I've fixed the former with help of flyspell-lazy, which works like a charm, but I see no solution to Smartparens problem except for writing an alternative package.

Installation

If you would like to install the package manually, download or clone it and put on Emacs' load-path, then you can require it in your init file like this:

(require 'para)

Usage

Coming soon…

Customization

Coming soon…

Why such name?

Para (пара, “а” sounds as “u” in “but”) means “pair” in Russian. The word is a good name for a package because it's quite unique and short and the same time.

License

Copyright © 2015–2016 Mark Karpov

Distributed under GNU GPL, version 3.