Thursday, April 24, 2008

Yeah, we've got one of those

Title linkey (which I discovered via slashdot) goes to an interview in DDJ with Paul Jansen, the creator of the TIOBE Programmer Community Index, which ranks programming languages according to their web presence (i.e. the size of the community interested in those languages). From the interview:

C and C++ are definitely losing ground. There is a simple explanation for this. Languages without automated garbage collection are getting out of fashion. The chance of running into all kinds of memory problems is gradually outweighing the performance penalty you have to pay for garbage collection.

So, to those people who balked at Objective-C 2.0's garbage collection, on the basis that it "isn't a 4GL", I say who cares? Seemingly, programmers don't - or at least a useful subset of Objective-C programmers don't. I frequently meet fellow developers who believe that if you don't know which sorting algorithm to use for a particular operation, and how to implement it in C with the fewest temporary variables, you're not a programmer. Bullshit. If you don't know that, you're not a programmer who should work on a foundation framework, but given the existence of a foundation framework the majority of programmers in the world can call list.sort() and have done with it.

Memory management code is in the same bucket as sorting algorithms - you don't need for everybody to be good at it, you need for enough people to be good at it that everyone else can use their memory management code. Objective-C 2.0's introduction of a garbage collector is acknowledgement of this fact - look at the number of retain/release-related problems on the cocoa-dev list today, to realise that adding a garbage collector is a much bigger enhancement to many developers' lives than would be running in a VM, which would basically go unnoticed by many people and get in the way of the others trying to use Instruments.

Of course, Objective-C and ApPLE's developer tools have a long history of moving from instrumental programming (this is what the computer must do) to declarative programming (this is what I am trying to achieve, the computer must do it). Consider InterfaceBuilder. While Delphi programmers could add buttons to their views, they then had to override that button's onClick() method to add some behaviour. IB and the target-action approach allow the programmer to say "when this button is clicked, that happens" without having to express this in code. This is all very well, but many controls on a view are used to both display and modify the value of some model-level property, so instead of writing lots of controller code, let's just declare that this view binds to that model, and accesses it through this controller (which we won't write either). In fact, rather than a bunch of boilerplate storage/accessors/memory management model-level code, why don't we just say that this model has that property and let someone who's good at writing property-managing code do the work for us? Actually, coding the model seems a bit silly, let's just say that we're modelling this domain entity and let someone who's good at entity modelling do that work, too.

In fact, with only a little more analysis of the mutation of Objective-C and the developer tools, we could probably build a description of the hypothetical Cen Kase, the developer most likely to benefit from developing in Cocoa. I would expect a couple of facts to hold; firstly that Cen is not one of the developers who believes that stuff about sorting algorithms, and secondly that the differences between my description of Cen and the description used by Apple in their domain modelling work would fit in one screen of FileMerge on my iBook.

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