Don't say "abstract" (instead say "general")

The word "abstract" is common in computer science. An abstract thing is one where some part of the whole is unspecified. For instance, the expression "3*x + 3" is an abstraction of the expression "3*4+3", because the "x" is unspecified. Likewise, a function is an abstraction over some set of values, supplied when the function is called.
The word "general" is not at all common in computer science. In non-computer-science use, the word "general" is used to describe things that may be applied to more than one thing or situation. For instance, a "more general solution" is one that applies not just to the problem at hand, but instead to a larger set of problems.
From a computer science perspective, things that are abstract are also general. Things that are general are also abstract. Substituting the word "general" for the word "abstract" would not be a terrible hurdle.
From a non-computer-science perspective, however, "general" and "abstract" have very different implications. Something that is general is better: it is more useful, it applies more frequently. Something that is abstract, though, is worse: it is lacking detail, it is non-concrete.
This is one difference--the major difference?--between computer science (and of course mathematics) and the real world: the abstract is no less concrete. We can abstract over expressions using functions, and we can even abstract over syntactic things, using hygienic macros. The result of such abstraction is a perfectly well-defined element in our universe of expressions.
In computer science, then, the pejorative sense of the word "abstract" is misleading, and the use of the terms "abstract" and "abstraction" merely provides ammunition for those who wish that we could all still be writing assembly language.
I suggest instead the use of the word "general."
John "purveyor of barbarous neologisms" Clements


Completions in DrScheme (finally)

DrScheme now supports a language- sensitive (but not lexical- scope sensitive) completion feature. Type <menukey>-/ and see what names are available to finish off the word you're typing.

Thanks to Jacob (and do follow that link; we all need a little more love in our lives) and Mike for taking the initiative to actually implement what is probably the most requested feature in DrScheme at the moment.


How many occurrences of car in the PLT source code?

Lets play a guessing game. See who can guess:

  • How many occurrences of the identifier 'car' there are in the PLT tree (when using 'read' and just counting the symbols that come out)?
  • Where does 'car' rank on the list of the most commonly used identifiers?
  • What is the most common identifier, and how many occurrences of it are there?
UPDATE: The two files raw-hattori and raw-kajitani.ss are generated files containing solutions to Paint by Numbers problems and about 30,000 occurrences of x and o. Discounting them, this is the list of the top ten identifiers and the number of occurrences:
((define 25294)
 (quote 24101)
 (lambda 18883)
 (let 14796)
 (send 14349)
 (x 11877)
 (if 11118)
 (... 8474)
 (car 7610)
 (syntax 6537))
The identifier cdr ranks 21st with 5,259 occurrences, let* has 3,066 which, when combined with let comes out at 17,862, still not enough to pass lambda. Speaking of combining, λ has 2,271 occurrences, which is also not enough to move lambda. Finally map comes in 32nd with 3,853 occurrences and foldl beats out foldr (1168th place with 75 occurrences vs 1451st place with 58 occurrences).


Birthday Easter Eggs in DrScheme

DrScheme has five birthday easter eggs in it, one for each of the main contributers to the PLT Scheme infrastructure (Matthias, Matthew, Eli, Shriram, and me). I put four of them in there, and mostly concentrated on making them fun. Matthew added mine and the best part of that one is figuring out on earth it shows up (it is quite tricky to find the code that actually makes that one appear).

I don't want to ruin the fun of searching for the Easter Eggs yourself, but just to get you started, do have a look at plt/collects/framework/private/bday.ss for Matthias, Matthew, Shriram, and Eli's birthdays. Mine is July 2nd.

Happy Hunting!