Thursday, January 22, 2015

Fluent 2014 Talk Summaries 3

"Speed, Performance and Human Perception"


In this performance-related talk, Ilya Grigorik explains that performance is not only a function of speed, but of meeting user expectations in a way that allows them to complete tasks effectively, with insightful examples.

[video]

My rating: 4/5. Provides useful insight on usability.

"Delivering the Goods"


Paul Irish discusses optimization in this keynote talk, describing the "critical path" and how requests impact page load times. Chrome developer tools are used to explain page load sequences and timing. Recommendations include: eliminate render-blocking JS; minimize render-blocking CSS; serve content in the original HTML response and use gzip compression. Google Page Speed Test is a tool to automatically recommend such optimizations.

[video]

My rating: 5/5. Beneficial recommendations for all developers of web-based software.

Tuesday, January 20, 2015

Fluent 2014 Talk Summaries, continued

"Reading, Writing, Arithmetic... and JavaScript?"


Pamela Fox, the person behind the JavaScript-based programming curriculum at Khan Academy, discusses how age affects a person's ability to learn programming and says that most 13 year olds are capable of learning basic programming skills that will help them explore other fields like art, history and language.  Visit Khan Academy for more information on their Computer Programming curriculum.


My rating: 3/5.  Introduces a great educational resource for young people. Plus, I've been a fan of Pamela's work ever since I read her articles on JavaScript widgets at Coursera.

[video]

"Virtual Machines, JavaScript and Assembler"


Popular podcaster Scott Hanselman delivers a humorous talk describing how the basic features of an operating system exist in both the cloud and the browser.

My rating: 3/5. Entertaining for programmers, though light on technical take-aways.

[video]

"The Humble Border-Radius"


In this talk Lea Verou demonstrates how border radii can be used to create a variety of shapes and animations, as well as upcoming CSS specifications for different corner shapes. While interesting, I think what web designers really want is complete flexibility to design arbitrary shapes, and border-radius seems like a very awkward mechanism for accomplishing that.

My rating: 3/5. Interesting CSS hacks.

[video]

Monday, January 19, 2015

Fluent Talk Summary: Brendan Eich, "JavaScript: the High and Low Roads"

In this lighthearted talk, Brendan Eich (inventor of JavaScript) discusses high and low-level improvements in upcoming versions of JavaScript. Acknowledging that Web development is hard ("like having a chain-saw in place of a hand"), Eich says the upcoming version of JavaScript, ES6 "Harmony", will address many difficulties facing web developers, with improvements like a built-in module system, observable objects, and many other features that will make "transpilers" and other "syntactic sugar" libraries unnecessary.

The future ES7 version of JavaScript aims to bring many low-level improvements for high-performance and scientific computing, including new value objects, operator overloading, and SIMD intrinsics. New value objects proposed in ES7 include: int64, uint64, int32x4 and int32x8 (SIMD), float32 (useful for GPUs), float32x4 and float32x8 (SIMD), bignum, decimal, rational, and complex. ES7 will also introduce operator overloading and new literals like 0L (int64), 0UL (uint64), etc. Support for SIMD (Single Instruction, Multiple Data) will lead to native performance for applications like game programming and signal processing. To demonstrate further, Eich reveals the first-ever public demo of the Unreal Engine 4 from Epic Games, showing stunning 3D graphics running at a full 60 frames per second, with no plugins, in a Firefox build with special SIMD capabilities.

Guided by the Extensible Web Manifesto, the high road of developer-friendly features and the low road of safe, low-level language improvements will converge in a virtual machine that offers native performance while being very developer friendly.

In a nutshell - "Always bet on JS!"

My rating: 4/5. Informative, insightful and entertaining for programmers.

Sunday, January 18, 2015

Dynamic Types FTW

There's a belief among some programmers, particularly the OO classical inheritance folks, that static typing is a bulwark of security against all kinds of disasters that may happen in your code.  They feel that the compiler will ensure their programs work correctly, by generating errors and warnings and refusing to compile their program until all the mistakes are fixed.

Some developers mistakenly speak in terms of "strong typing" and "weak typing". Put that way, who wouldn't prefer "strong" over "weak" typing? In reality the terms "strong typing" and "weak typing" are undefined in the language of computer science. They're misnomers that people sometimes use to talk about strict (explicit) type definition with static type checking, versus dynamic (runtime) type checking with implicit type conversion.

It's unfortunate that this line of reasoning causes some people to avoid languages that offer dynamic types. Dynamic types can be very useful, and static typing actually offers very little in the way of ensuring program correctness.  I finally sat down and watched Eric Elliott's presentation "Static Types are Overrated: The Dynamic Duo - Loose Types and Object Extension" and was treated to a bang-on description why static types aren't all they're cracked up to be.  Eric does a good job of explaining and clarifying things about JavaScript and programming in general that I intuitively believed but had a difficult time putting into words or backing up with solid examples.

I borrowed a bunch of points from Eric's talk when I spoke at a recent Ottawa JavaScript meetup. I was presenting on Flow, a static type checker for JavaScript, but I wanted people to see it as something that could be added to their regular code linting process rather than something to enforce a statically typed programming style. Here are some of them.
  • It's a myth that dynamic loosely typed languages like JavaScript aren't suitable for building large, complex applications.  There are dozens of examples from Facebook to 37signals, Dow Jones, Adobe, Flickr, LinkedIn, Walmart, etc).
  • Type correctness does not guarantee program correctness. This is one of the biggest cargo-cult myths out there: thinking that static, strict type checking will save you. It won't.
  • When languages lack dynamic types, people fake it with ugly hacks - void pointers, variadic functions, abusing array accessors, type-casting of all sorts, generics and ugly template classes, to name a few. I don't know any C or Java programmers who haven't used and abused at least a few of these techniques.
  • "Any sufficiently advanced C / Fortran [Java, etc] program contains an ad hoc, informally specified, bug-ridden, slow implementation of half of common Lisp" - Greenspun's Tenth Rule. (There are no rules 1 through 9, by the way. Greenspun's Rules of Programming start and end with number 10.)
  • Older statically typed languages are now introducing dynamic types because they really are useful. Objective-C added them a long time ago; more recently C++11 has added dynamic types, Java has "generics", and libraries like cppscript and boost provided ways to do dynamic types in earlier versions of C++.
  • Functional programming benefits from functions that can operate on any type which implements its requirements (for example, arguments have a valueOf method). Otherwise known as duck typing. This permits things like map, filter, forEach etc. to be used generically.
  • Correctness can only really be assured through proper unit and integration testing. 
  • Code that is well organized in small, simple modules, linted, unit tested, peer reviewed, and integration tested, is very unlikely to contain type errors. 

The last thing I would add is that while static types are over-rated, static code analysis tools like JSLint, Tern.js and Flow are mostly underrated and underutilized. If you use something like Flow or Tern.js to provide hints and insights into potential type mismatches, the chances of type errors become essentially zero. Ideally they should be as up-front as possible, i.e. integrated directly into your code editor. I wrote a JSLint plugin for SublimeText and recently wrote a Flow plugin as well. They provide immediate static code analysis warnings as I edit my code, so I can fix problems before I commit anything to the source code repository.

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