JavaScript

The anti-JavaScript

Posted on by John

The problems with JavaScript come from premature standardization. The language’s author Brendan Eich said

I had to be done in ten days or something worse than JS would have happened.

For a programming language designed in 10 days, he did an amazing job. Maybe he did too good a job: his first draft was good enough to use, and so he never got a chance to fix the language’s flaws.

The opposite of JavaScript may be Perl 6. The language has been in the works for 12 years and is still in development, though there are compilers you can use today. An awful lot of thought has gone into the language’s design. Importantly, some early design decisions were overturned after the community had time to think, a luxury JavaScript never had.

Perl 6 has gotten a lot of ridicule for being so slow to come out, but it may have the last laugh. Someone learning Perl 6 in the future will not care how long the language was in development, but they will appreciate that the language was very thoughtfully designed.

* * *

Another contrast between JavaScript and Perl 6 is their names. Netscape gave JavaScript a deliberately misleading name to imply a connection to the Java language. The Perl 6 name honestly positions the new language as a successor to Perl 5.

Perl 6 really is a new language, compatible in spirit with earlier versions of Perl though not always in syntax. Damian Conway has suggested that perhaps Perl 6 should have been developed under a completely different name. Then after it was completed, the developers could announce, “Oh, and by the way, this language is the upgrade path for Perl.”

If you think of Perl 6 as a new language, your expectations are quite different than if you think of it as an upgrade. If it’s a new language, it doesn’t matter so much how long it was in development. Perl programmers would be pleased with how similar the new language is to their familiar one, rather than upset about the differences. And people would evaluate the new language on its merits rather than being prejudiced by previous experience with Perl.

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The virtual machine of the Internet

Posted on by John

From Douglas Crockford’s talk The State and Future of JavaScript:

There’s pressure to make it [i.e. JavaScript] a better compilation target. Now, this is a big surprise. Everybody thought that the Java VM was going to be the VM of the Internet, but it turns out that JavaScript language is the VM [ virtual machine ] of the internet. People are writing in Java, and Python, and lots of other languages, and then translating it into JavaScript because JavaScript, for all of its security problems, actually has a much better security model than everybody else.

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Zero-knowledge password management in JavaScript

Posted on by John

The most recent guest on Jon Udell’s Interviews with Innovators podcast was Marco Barulli. Barulli discusses Clipperz, a zero-knowledge password management application. The software encrypts passwords (or arbitrary text) using client-side JavaScript. Your data is encrypted on your computer and the encrypted version is uploaded to the Clipperz server. When you want to retrieve your data, the encrypted data is downloaded to your computer and decrypted there. Your unencrypted data never leaves your computer.

For more information, see the article on Jon Udell’s blog or listen to the podcast. Even if you’re not interested in using the Clipperz product, you may find the discussion of JavaScript and cryptography techniques interesting.

Programming book I wish someone would write: R, The Good Parts

Posted on by John

Douglas Crockford’s book JavaScript: The Good Parts is terrific. Crockford is both a critic of and advocate for JavaScript. He’s quite frank about the language’s faults. His book is the clearest exposition of the pitfalls of JavaScript that I’ve seen. But he also believes there’s a great language at the heart of JavaScript. He doesn’t just complain about the bad parts; he explains how to avoid them. He has identified his recommended subset of the language. He has written programming style guide intended to increase the chances that JavaScript code does what the programmer intends. And he has written a tool, JSLint, to warn of potential problems. (Crockford reminds me of Luke Skywalker, convinced that there is good in Darth Vader and determined to rescue him from the dark side of the force.)

I wish someone would write a book for R analogous to the one Crockford wrote for JavaScript.

The R language has a lot in common with JavaScript. Both are Lisp-like languages at their core with C-like syntax. Both are dominant languages in their respective niches: R in academic statistics and JavaScript in web browsers. (R doesn’t have the monopoly in statistics that JavaScript has in the browser, but it’s still pervasive.) Both languages are powerful but maddening to debug. JavaScript has an undeserved reputation for being ugly because it is typically used to program the browser DOM; it’s the DOM that’s buggy and non-standard, not JavaScript. Similarly, R’s reputation may suffer from the numerous poorly written modules implemented in R.

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Programming language fatigue

Posted on by John

Joe Brinkman wrote an insightful article the other day, Ployglot Programming: Death By A Thousand DSLs. Here’s an excerpt:

I don’t know about other programmers, but I am drowning in DSLs [domain specific languages].  It is hard enough keeping up with my primary development language and the associated platform APIs, but these DSLs are going to be the death of me.  The end result is that I have a pretty decent handle on maybe 3 or 4 of these DSLs but rarely do I have the requisite knowledge to make the right choices in anything beyond that.

It takes a dozen programming languages to do any web project these days. Whenever I bring this up in conversation, most developers say “Oh, well. That’s just the way it is. It isn’t so bad.” But I think it really is a problem. Obviously it’s intimidating amount of material for new developers to learn. But the more subtle problem is that experienced developers who think they understand all the different languages they use are probably wrong.

Case in point: JavaScript. Nearly every web project involves some client-side JavaScript, and 99% of the people who write JavaScript do not know the language. I never claimed to be a JavaScript expert, but I thought I understood the language better than I really did until I saw some presentations by Douglas Crockford.

Crockford has written an excellent book: JavaScript: The Good Parts. His position is that there is an elegant, powerful language at the core of JavaScript but it is surrounded by landmines. His book focuses on the good parts, but along the way he tells you how to avoid or disarm the landmines.

Related post: Programming language subsets

Syntax coloring for code samples in HTML

Posted on by John

Syntax coloring makes it much easier to read source code, especially when you become accustomed to a particular color scheme. For example, I’m used to the default color scheme in Visual Studio: comments are green, keywords are blue, string literals are red, etc. Once you get used to color-coded source code, it’s hard to go back to black-and-white. However, the code samples here are monochrome and I’ve been thinking about doing something about that.

It’s possible to mark up code samples on the web just like any other chuck of HTML, but that would be time-consuming. Also, you want to leave code samples as plain text so readers can copy the source and paste it into their code. So what people usually do is use client-side JavaScript to change the way code samples are displayed in the browser. That way the code appears to be marked up but it’s still unadorned underneath.

I like the way code samples look on Scott Hanselman’s blog, and so I started to use the JavaScript solution that he recommends, SyntaxHighlighter. However, I decided to hold off when I read this comment on his blog.

I tried to use it. Unfortunately the scrolling errors I see on your and other sites are too much to bear.

More recently I heard that StackOverflow is using prettify.js to add syntax coloring for their code samples. I haven’t noticed any problems on that site, so I’m starting to try out prettify. I’ve heard that the script doesn’t always handle VB code correctly, but that doesn’t matter to me.

The prettify script is easy to use. You don’t have to tell it what programming language you’re highlighting. However, you do have the option of  specifying the language, which presumably can’t hurt. I’ve tried it on a page containing C++ code and on another page containing Python code and they both look OK. My only complaint is that the default color scheme is not what I would have chosen. However, the color scheme can be modified by editing a style sheet and I intend to do that.

I’m going to start by experimenting with static files on my site. I’m more cautious about incorporating syntax coloring with the blog since I don’t know what interaction problems there could be with the WordPress software on the server or with blog reader software on the clients. Scott Hanselman says on his blog

… I couldn’t find a syntax highlighting solution that worked in EVERY feed reader. There are lots of problems with online ones like Google Reader and BlogLines if I, as the publisher, try to get tricky with the CSS.

So I may leave the code samples on the blog alone. Also, I’m also not sure what I’ll do about PowerShell samples. The prettify script works well with C-family languages, but PowerShell syntax may be too far afield from what it expects.

Does anyone have suggestions in general? For PowerShell in particular?

Web 2.0 over dial-up

Posted on by John

I’m borrowing an old Pentium III computer with a dial-up Internet connection. I haven’t used dial up in a long time and was surprised what a difference bandwidth makes. Many “Web 2.0” sites are just painful to use. Some simply do not work. One site gave me a message essentially saying to go away and come back with a better connection.

However, StackOverflow was a pleasant surprise. I thought that since it uses a lot of client-side JavaScript, the site would be just as sluggish as the others I tried. It takes a while to log in, but after that the site is easy to use over a slow connection. The developers of the site must have thought about conserving bandwidth; I find it hard to believe that the excellent low-bandwidth performance was an accident. Very impressive.

Programming language subsets

Posted on by John

I just found out that Douglas Crockford has written a book JavaScript: The Good Parts. I haven’t read the book, but I imagine it’s quite good based on having seen the author’s JavaScript videos.

Crockford says JavaScript is an elegant and powerful language at its core, but it suffers from numerous egregious flaws that have been impossible to correct due to its rapid adoption and standardization.

I like the idea of carving out a subset of a language, the good parts, but several difficulties come to mind.

  1. Although you may limit yourself to a certain language subset, your colleagues may choose a different subset. This is particularly a problem with an enormous language such as Perl. Coworkers may carve out nearly disjoint subsets for their own use.
  2. Features outside your intended subset may be just a typo away. You have to have at least some familiarity with the whole language because every feature is a feature you might accidentally use.
  3. The parts of the language you don’t want to use still take up space in your reference material and make it harder to find what you’re looking for.

One of the design principles of C++ is “you only pay for what you use.” I believe the primary intention was that you shouldn’t pay a performance penalty for language features you don’t use, and C++ delivers on that promise. But there’s a mental price to pay for language features you don’t use. As I’d commented about Perl before, you have to use the language several hours a week just to keep it loaded in your memory.

There’s an old saying that when you marry a girl you marry her family. A similar principle applies to programming languages. You may have a subset you love, but you’re going to have to live with the rest of the language.