Lacunas Everywhere

I’m told that in Czech, the word “prozvonit” means “to call a mobile phone and let it ring once so that the other person will call back, saving the first caller money.”

Image credit: AstridWestvang (Flickr)

How would you translate this word to someone in New Guinea who has never experienced electricity, let alone a telephone or a bill from Verizon? You wouldn’t. This is an example of a “lacuna“–a translation problem caused by semantic gaps in a target language. Lacunas occur in programming languages. You might know a few; maybe you wish C++ had python-style generators–or that Java had Haskell’s notion of pure functions–or that C supported PHP-style string interpolation. But what if I told you that semantic misalignment between any pair of programming languages is just minor details? What if I claimed that all programming languages I’ve used have numerous, pernicious, and expensive semantic gaps? That we don’t see these gaps for the same reasons that a stone-age hunter-gatherer fails to notice his inability to discuss patterns of cell phone usage? Would you think I’m crazy? Continue reading

Headers, babies, and bathwater

I claim that by eliminating the C/C++-style dichotomy between headers and implementation, most modern programming languages have thrown out the baby with the bathwater.

Don't throw out the baby with the bathwater! Photo credit: StubbyFingers (Flickr)

Don’t throw out the baby with the bathwater! Photo credit: StubbyFingers (Flickr)

If that sounds crazy, just hang with me for a minute.

I know my claim runs counter to popular wisdom; have a look at this thread on Designers of languages like python and go and D and ruby and java consider it a feature that developers don’t have two redundant pictures of the same functionality. This comment from the C# 5.0 specification is typical:

“Because an assembly is a self-describing unit of functionality containing both code and metadata, there is no need for #include directives and header files in C#. The public types and members contained in a particular assembly are made available in a C# program simply by referencing that assembly when compiling the program” (p 3).

I agree.

Sort of…

Bad headers are a royal pain

It can be onerous to maintain the parallelism between a .h and a .cpp. And most C/C++ headers are managed so poorly that the benefits you might claim for them are theoretical rather than real. Three common antipatterns that I particularly detest: Continue reading

// Comments on Comments


We spend little or no time teaching programmers how to write good comments.

This is surprising, when you consider how often “total lack of comments” or “poor comments” are cited as evidence that certain modules (or the programmer who wrote them) are the worst thing that ever happened to the technoverse.

Comments shouldn’t leave you–or anybody else–mystified. :-) Image credit: xkcd

I happen to think that there are much yuckier tech things than poor or missing comments in code. But I still think our general level of comment proficiency is lower than it should be.

Here is my attempt to raise the bar a little.

Why We Comment

Sooner or later, most interesting programming problems require a sophisticated mental model of a problem. Building these models is hard work, and once we have them, we are paid to share with our team (or our future selves).

The best way to share mental models with other engineers is Continue reading