Category: Link

Emacs Lisp programmers must know about pcase

Pattern matching is available in a bunch of programming languages. For some reason, I never thought to look for a library in Emacs Lisp for it, and it is here in pcase.
There is this weird thing that happens when you start using Emacs Lisp. Unlike other languages where you start learning it for “its great features”, most of us only learned it to configure Emacs. Because of this, our brains kind of turn off when it comes to using the language. Or perhaps instead, our expectations change. They are just, lower, and it makes our minds slower. That is why you see so many posts like “if you are programming Emacs Lisp then you must…”.

A faster rsync for Vagrant

[vagrant-gatling-rsync is ] an rsync watcher for Vagrant 1.5.1+ that uses fewer host resources.

How it works:

The built-in rsync-auto plugin sometimes uses a lot of CPU and disk I/O when it starts up on very large rsynced directories. This plugin is designed to work well with such large rsynced folders.
The rsync-auto command that ships with Vagrant 1.5 uses the listen gem. The Listen gem is quite thorough – it uses Celluloid to spin up an actor system and it checks file contents on OS X to ensure that running “touch” on a file (to do a write but not update its content) will not fire the rsync command.
The downside of using Listen is that it takes a large amount of host resources to monitor large directory structures. This gem works well with to monitor directories hierarchies with 10,000-100,000 files.
This gem’s implementation is much closer to the underlying fsevent or inotify APIs, which allows for higher performance.

Realtime web development with skewer and Emacs

[skewer-mode] provides live interaction with JavaScript, CSS, and HTML in a web browser. Expressions are sent on-the-fly from an editing buffer to be evaluated in the browser, just like Emacs does with an inferior Lisp process in Lisp modes.

Looks like a pretty nice option if you are used to Emacs already and so much more pleasant then running code in the Chrome/Firefox/IE REPL.