D, meanwhile, had been in the top 20 from 2007 until the middle of 2009 and was ranked 20 in the September report. Tiobe points to a Wikipedia reference about the release of a book entitled "The D Programming Language," by Andrei Alexandrescu, in June 2010, as a possible reason for the language's comeback. The D language is from Digital Mars and can be viewed as somewhat of a successor to C++, although C++ is still popular, said Paul Jansen, founder and chief community officer of Tiobe, which assesses software quality: "D is in fact a clean design of C++."
D displaces the F# language, which briefly cracked the Tiobe top 20 last month. , was ranked No. 20 in August, its first-ever entrance in the top 20. But it dropped to the 23rd-most popular language in the September report.
But F#, representing a new generation of functional languages, can be expected to quickly return to the top 20, Jansen said: "It's a functional language, which means that it is a completely different way of programming. There have been a lot of functional languages around so far, and the most famous one is Lisp."
Java remains No. 1 on the Tiobe list, followed by C, C++, C#, and PHP. Between Objective-C and D, the top 20 was filled out by Visual Basic, Python, Perl, JavaScript, Ruby, Delphi/Object Pascal, Lua, Lisp, Transact-SQL, Pascal, PL-SQL, Ada, and RPG (OS/400). Java has been the top language for 10 years, except for a few months when it was eclipsed by C, Jansen said.