When good comments mean bad language

I’ve had an epiphany.

For years, I’ve urged developers to write better comments. I still claim that’s a good idea (a very good one), but as I’ve pondered what a better programming language might look like, I’ve come to an important conclusion:

A lot of “best practice” commenting is just workarounds for inadequate language design.

This might seem like a crazy or arrogant claim. The Wirths and Matsumotos and Hejlsbergs and van Rossums and McCarthys of the world are incredibly smart people; how could I claim to know something that they do not? Each of these language designers has probably forgotten more about computer science than I will ever learn.

And yet, I think Randall Munroe (the cartoonist at xkcd) was right to make fun of our industry’s facile assumption that context-free grammar is all you need to know about formal language:

image credit: xkcd.com

To show you what I mean, I’ve inlined snippets of code from a variety of programming languages below. Don’t worry about digesting them carefully right now, but give them a quick glance and then move on to my analysis, and see if you agree with my claim about an unhealthy pattern. Continue reading

Good fences make good neighbors

In Robert Frost’s poem, “Mending Wall”, two farmers meet each spring to rebuild the rock wall between their properties. One farmer is the narrator. He notes that the unseen forces of winter and weather always cause some decay (“something there is that doesn’t love a wall”), and he wonders why the wall is necessary. There’s apple orchard on one side, and pine forest on the other–it’s not as if something will be kept in or out. The other farmer answers with the repeated aphorism “good fences make good neighbors.”

photo credit: DragonWoman (Flickr)

This poem could be a treatise for the principle of encapsulation in software. In software as in life:

  • Something there is that doesn’t love a wall.
  • Good fences make good neighbors.

What doesn’t love a wall?

Subroutines, formal interfaces, data hiding, class hierarchies, the pimpl idiom, and similar mechanisms all create barriers in software between consumers and providers of functionality. These techniques are well known, but we still have codebases littered with protected data members, unnecessary class declarations in headers, goto, and other suboptimal choices.

Why? Continue reading

Programming Language Popularity Index

Here’s an interesting chart, giving a realtime view of which programming languages have high mindshare. The chart has one axis devoted to number of lines in code commits on GitHub, and another to how often the language shows up in tags on StackOverflow.


Programming languages: what’s hot (top right), what’s not (bottom left). Top 3 rows of buttons are clearly where mindshare is at in the industry. Click for details.

I don’t think the chart is perfect. I’ve seen it billed as a “popularity index,” but I think it might be better described as a measure of how busy the coders are who use each language. If most of the coders who use a language hate it, I don’t think it’s fair to call it “popular.” Some apples-to-apples issues are glossed over, such as the fact that certain languages are very verbose, and some languages tend to get used mostly for “big” projects or for “small” ones. And the chart says nothing about the quality of systems built with the languages, or about the velocity of teams.

Continue reading