During last week’s WWDC keynote address, Apple announced that it would be making its Swift programming language open source later this year. The move to open-source Swift is part of Apple’s efforts to be more open with developers and should surely help to encourage programmers to learn and start using this new language. However, it’s pretty clear that, even before it goes open source, usage of Swift has been steadily increasing, seemingly at the expense of the language it was designed to replace as the platform of OS X and iOS development, Objective-C.
This month’s TIOBE Index of programming languages, which ranks languages based on web searches, has Swift 14th, which was up from 18th in May and 25th in January. After its first 6 months of release, where it saw a spike in interest then some drop-off, Swift’s market share of web searches has been increasing steadily all year and is now up to 1.4%. Objective-C is currently ranked 5th by TIOBE, down from 4th in May and 3rd in January. It’s been losing market share of web searches since its peak in April 2014, when it had a 12.9% share, and is currently at 4.3%. The TIOBE editors say Objective-C has been losing about 1% of market share per month and, if it continues to slip at that rate, will drop out of the top 20 by the end of the year.
The Popularity of Programming Languages (PYPL) index for June, which is based on web searches for tutorials about programming languages, has Swift ranked 11th, up from 12th in January, with its market share increasing from 2.5% to 2.7% over that time period. Objective-C is current 8th on PYPL, where it has been ranked for the last year, but its share of web tutorials has continued to drop, now down to 5.5%, compared to 6.1% in January and 6.6% last June when Swift was first released.
Finally, the shift from Objective-C to Swift is also noticeable when looking at GitHub activity. From July through December of 2014, the first six months after its was released, Swift repos made up 0.65% of all non-forked repositories created during that time, compared to 1.6% for Objective-C. Since then, from January 1 through the end of May, Swift's share of new repos has increased to 0.8% while Objective-C’s share has dropped to 1.4%.
We see, then, that developer interest in Swift continues to grow, despite the fact that seasoned iOS/OS X programmers are taking a careful approach to the transition from Objective-C. The move to open-source Swift will likely increase the rate of adoption, since it will now to be open for use beyond iOS and OS X. It will be interesting to see which languages, other than Objective-C, start to yield market share to Swift. I’ll be sure to keep an eye on how it plays out.