Of these 3, at least 2 would depend on the language in use: "We used a combination of lexical features (e.g., variable name choices), layout features (e.g., sp

Of these 3, at least 2 would depend on the language in use: "We used a combination of lexical features (e.g., variable name choices), layout features (e.g., spacing), and syntactic features (i.e., grammatical structure of source code)" In particular, "layout features" is a huge issue in some languages, and not at all in others. For instance, a language like Javascript, or PHP, give great flexibility about layout, so in those languages I can see each developer having a unique style (and I have been involved in style debates regarding those languages), however, a language like Python has a fairly fixed layout, since the whitespace is significant. And also, in Clojure, I think most programmers use Emacs and accept the Emacs clojure-mode indenting as the default. Variable name choices is another where some environments encourage similarity, and others allow for unpredictability and unique styles. Within the Ruby On Rails framework, for instance, there are norms about the creation of variable names. I would guess that syntactic features is perhaps the one characteristic that shows a great deal of uniqueness in every language. I am often surprised at the choices my fellow co-workers make, when it comes to how to solve a problem.