Thought Palace

Terra: A low-level counterpart to Lua

eyepool — Fri, 17 May 2013 10:28:44 -0700

Terra is a new low-level system programming language that is designed to interoperate seamlessly with the Lua programming language:

Like C, Terra is a simple, statically-typed, compiled language with manual memory management. But unlike C, it is designed from the beginning to interoperate with Lua. Terra functions are first-class Lua values created using the terra keyword. When needed they are JIT-compiled to machine code.

—Zach DeVito, Stanford

new-aesthetic: “An ode to the journey of ó on a shipping label”...

eyepool — Mon, 13 May 2013 16:36:46 -0700

new-aesthetic:

“An ode to the journey of ó on a shipping label” found at http://i.imgur.com/4J7Il0m.jpg, via @shyhoof.

Go 1.1 is released

eyepool — Mon, 13 May 2013 15:24:20 -0700

Go 1.1 is released:

Go 1.1 includes many improvements over 1.0.

The most significant improvements are performance-related. We have made optimizations in the compiler and linker, garbage collector, goroutine scheduler, map implementation, and parts of the standard library. It is likely that your Go code will run noticeably faster when built with Go 1.1.

There are some minor changes to the language itself, two of which are worth singling out here: the changes to return requirements will lead to more succinct and correct programs, and the introduction of method values provides an expressive way to bind a method to its receiver as a function value.

Concurrent programming is safer in Go 1.1 with the addition of a race detector for finding memory synchronization errors in your programs. We will discuss the race detector more in an upcoming article, but for now the manual is a great place to get started.

JChris: “Stuart Langridge from Canonical wearing the best...

eyepool — Fri, 10 May 2013 15:02:32 -0700

JChris: “Stuart Langridge from Canonical wearing the best t-shirt inspired by an HTTP proxy bug ever.”

Douglas Crockford (JavaScript guru and originator of JSON)...

eyepool — Wed, 08 May 2013 11:47:47 -0700

Douglas Crockford (JavaScript guru and originator of JSON) models one of our Couchbase “You Had Me At JSON” t-shirts at QCon Tokyo

new-aesthetic: Twitter / redcatco: “We live in a world where...

eyepool — Tue, 09 Apr 2013 12:29:32 -0700

new-aesthetic:

Twitter / redcatco: “We live in a world where even trash cans can kernel panic.”

Mistitled: The Gathering Storm: Our Travails with iCloud Sync

eyepool — Sun, 31 Mar 2013 12:13:57 -0700

Mistitled: The Gathering Storm: Our Travails with iCloud Sync:

rms2:

Preface

Recently, and with increasing frequency, developers have been speaking out about the difficulties they’ve had trying to implement support for iCloud in their products, and journalists have been reporting the news. I told our story to Ars Technica, and they’ve made their own report….

ArsTechnica: Frustrated with iCloud, Apple’s developer community...

eyepool — Thu, 28 Mar 2013 11:41:16 -0700

ArsTechnica: Frustrated with iCloud, Apple’s developer community speaks up en masse

See also recent coverage at The Verge, and a great blog post by Brent Simmons on “Why Developers Shouldn’t Use iCloud Syncing, Even If It Worked”.

This is a great opportunity for Couchbase’s mobile technologies (which I work on) — TouchDB, and the upcoming Couchbase Lite and Couchbase Sync Gateway.

How To Build An RSS Sync System: A Brain-Dump

eyepool — Wed, 13 Mar 2013 22:44:00 -0700

Problem Statement: Google pulled the plug on Reader, but you still want a way to keep the news-reader apps on your various devices in sync, so they all know what feeds you’re subscribed to and which articles you’ve already read.

Here’s what you do. I’ve built this before, as part of the OS X Syndication and PubSub frameworks. (It wasn’t identical to what I’m describing here, partly because app.net didn’t exist so I had to do some clever things with hidden file storage on mac.com. Aren’t you lucky?)

Find a protocol that lets you publish and subscribe to small messages in store-and-forward fashion. Yay, this is already done! It’s the app.net Messaging API.
Define a custom channel type for RSS sync.
Create a channel in the user’s account, with ACL such that only that user can access it (i.e. private.)
Encode the current subscription list somehow — probably as a tree of JSON objects containing the feed names and URLs — and save it as an attachment on the channel.
Periodically check whether the content of this attachment has changed; if so, download it and update your app’s subscription list from it.
Define an algorithm for identifying a news article by a unique digest. Basically you collect the attributes that identify the article and run them and the feed URL through something like SHA-1. These attributes could be just the article UUID if the feed includes those; else the permalink; else the title, else the body. (If you’ve written a newsreader you know what I’m talking about and have probably done this already. It’s just that for compatibility, all apps have to agree on the details of the encoding.)
When the user marks articles as read, remember their digests. Periodically bundle up the recent digests and publish them in a message to the channel.
When messages arrive on the channel, unpack them into lists of article digests. Mark every such article as read. Remove any such articles from the recently-marked-as-read list described in the previous step.

That’s pretty much it. Note that the traffic in this channel is pretty low: if a digest is 20 bytes (ok, 30 in base64), and a user reads a few hundred articles a day, that’s a few kbytes of data a day. No problem. The number of messages can be tuned by changing the heuristic for how long to wait to post to the channel after the user reads a message. Waiting a couple of minutes seems reasonable, as long as you make sure to post before the user quits or deactivates the app.

A newly installed app will want to reach back into the channel’s history to find out what articles are already read. How far back is arbitrary, but it depends on how long articles stay in the RSS feeds. You can do something like reading through the last two weeks of the channel, and then assuming any article from a feed that’s older than two weeks must already be read. It’s not 100% accurate but it’s pretty close. (And this issue only applies to newly installed apps.)

“Starring” or favoriting articles works the same way as marking them as read. You just need something like an additional bit of metadata on each digest to determine whether the article is starred or not. (With additional bits you can indicate more state like an article that’s been explicitly marked unread again.)

As I re-read this, I’m remembering some interesting edge cases and details that I don’t want to get into here. They’re not rocket science, so I’ll leave them as exercises for the reader. If you want clues, just ask…

Hi Jens, I believe in Couchbase you had an embedded Erlang RT suitable for iOS; is this still the case in Touchbase? Thanks, Oliver

eyepool — Sat, 23 Feb 2013 16:34:27 -0800

The old Couchbase Mobile had an embedded Erlang, yes. That’s what made it so big and slow, unfortunately. TouchDB and Couchbase Lite are written natively in Objective-C with no interpreters.

spam tip

eyepool — Tue, 08 Jan 2013 13:50:39 -0800

Want to cut down on email spam? Add a filter to your email program that will trash any messages whose From address starts with “contact@”.

I set up such a filter two weeks ago, and so far it’s caught about 90% of the junk that otherwise makes it through even my ISP’s and Apple Mail.app’s spam blockers. (I think there may have been one false positive, but not more. Apparently almost no one sends real email from a contact@ address.)

(FYI, all of these spams seem to be the result of one network. They’ve recently implemented a trick to work around DomainKey, which is an anti-spam measure that digitally signs an email message to prove that it legitimately came from the email domain in its From address. DomainKey is great for stopping spam with forged @gmail.com or @amazon.com addresses, but what these spammers have done is registered a buttload of randomly-named domains and installed DomainKey on them, so they can send out spam with valid DomainKey signatures from their domains. The signature gives spam-filters a warm fuzzy feeling about the message, making it less likely to be marked as spam. Presumably the anti-spam folks are blacklisting these domains as fast as they can, but it’s easy for the spammers to keep registering more. I don’t know where this particular arms race will end.)

"There are only two hard things in computer science: cache invalidation, naming things, and..."

eyepool — Wed, 19 Dec 2012 17:31:49 -0800

“There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors.”

- Martin Fowler, intentionally misquoting Phil Karlton

iTunes 11 and Colors

eyepool — Tue, 11 Dec 2012 15:51:15 -0800

iTunes 11 and Colors:

“iTunes 11 is a radical departure from previous versions and nothing illustrates this more than the new album display mode. The headlining feature of this display is the new view style that visually matches the track listing to the album’s cover art. The result is an attractive display of textual information that seamlessly integrates with the album’s artwork.

“After using iTunes for a day I wondered just how hard it would be to mimic this functionality — use a source image to create a themed image/text display.”

—Wade, from Panic

He goes on to provide an open source library to compute these colors for any image. Nice.

"IDEKit is a framework designed to make it easy to add programmer friendly editors to existing..."

eyepool — Tue, 11 Dec 2012 08:08:05 -0800

““IDEKit is a framework designed to make it easy to add programmer friendly editors to existing programs, or design a whole project based IDE. It includes support for plugins for languages, syntax coloring, preference panels, etc… See the release notes for more details. It was designed to work with both 10.2 and 10.3 originally, and was built using Xcode 1.1 (targeting 10.2.7). IDEKit was forked internally at Apple, and is the basis for Xcode’s editing capabilities, syntax highlighting, and project format. It is a highly complicated framework, and as such, is a little unstable at the moment.””

- CodaFi/IDEKit · GitHub

Old blog archive at last

eyepool — Sat, 27 Oct 2012 17:56:17 -0700

Old blog archive at last:

I exported the old Thought Palace WordPress blog posts from MySQL and wrote a little Ruby script to massage them into Jekyll format so I can host them on Github. Here they are — yes, even the apricot jam recipe.

The theme is kind of lame, and there are probably some formatting glitches and definitely some missing graphics, but the text is there.

Any chance you'll be uploading your archive to this site? "The Lost Lesson of Instant Typing" was a great piece and I was looking for it again to share with someone.

eyepool — Fri, 26 Oct 2012 19:16:53 -0700

I really should! Unfortunately I think I’d have to dig them out of the MySQL database and then convert the Textile to Markdown, and I keep finding better things to do with my weekends…

In the meantime, the WaybackMachine still has archives of my old blog.

Galuca Icons Project

eyepool — Mon, 08 Oct 2012 09:45:59 -0700

Galuca Icons Project:

Galuca is a special project to develop FREE high-quality, high-resolution icons for iOS, Android and Windows Phone apps.

Galuca is aimed at helping professional and freelance developers when designing and choosing stunning icons for their apps with minimum time and no cost.

All Galuca project’s icons are designed, developed and distributed freely according to Creative Commons Attribution license v3.

Just watch out; there are a couple of icons using trademarks in there, like the Playboy bunny, UPS logo, Olympic rings…

webkitmemes: Debugging JavaScriptCore.

eyepool — Thu, 04 Oct 2012 17:39:13 -0700

webkitmemes:

Debugging JavaScriptCore.

Dilbert (Except for the words “large-scale”, he...

eyepool — Thu, 06 Sep 2012 11:27:42 -0700

Dilbert

(Except for the words “large-scale”, he might be talking about TouchDB…)

A successful Git branching model » nvie.com

eyepool — Thu, 23 Aug 2012 13:37:36 -0700

A successful Git branching model » nvie.com:

In this post I present the development model that I’ve introduced for all of my projects (both at work and private) about a year ago, and which has turned out to be very successful. I’ve been meaning to write about it for a while now, but I’ve never really found the time to do so thoroughly, until now. I won’t talk about any of the projects’ details, merely about the branching strategy and release management.