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Delphi anonymous methods - pro and cons. Good practices when using closures(anonymus methods) in Delphi

Asked 2011-10-19T08:48:45.740
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I have a colleague in my team which is extensively using closures in our projects developed in Delphi. Personal, I don't like this because is making code harder to read and I believe that closures should be used ONLY when you need them.

In the other hand I've read Can someone explain Anonymous methods to me? and other links related to this, and I'm taking into account that maybe I'm wrong, so I'm asking you to give me some examples when is better to use closures instead of a 'old-fashion' approach (not using closures).

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I believe that this question calls for a very subjective judgement. I am an old-school delphi developer, and inclined to agree with you. Not only do closures add certain risks (as David H points out in comments) they also reduce readability for all classically trained Delphi developers. So why were they added to the language at all? In Delphi XE, the syntax-formatting function and closures weren't working well together, for example, and this increased my mistrust of closures; How much stuff gets added to the Delphi compiler, that the IDE hasn't been fully upgraded to support? You know you're a cranky old timer when you admit publically that you would have been happy if the Delphi language was frozen at the Delphi 7 level and never improved again. But Delphi is a living, powerful, evolving syntax. And that's a good thing. Repeat that to yourself when you find the old-crank taking over. Give it a try.

I can think of at least ten places where Anonymous methods really make sense and thus, reasons why you should use them, notwithstanding my earlier comment that I mistrust them. I will only point out the two that I have decided to personally use, and the limits that I place on myself when I use them:

  1. Sort methods in container classes in the Generics.Collections accept an anonymous method so that you can easily provide a sorting bit of logic without having to write a regular (non-anonymous) function that matches the same signature that the sort method expects. The new generics syntax fits hand in hand with this style, and though it looks alien to you at first, it grows on you and becomes if not exactly really nice to use, at least more convenient than the alternatives.

  2. TThread methods like Synchronize are overloaded, and in addition to supporting a single TThreadMethod as a parameter Thread.Synchronize(aClassMethodWithoutParameters), it has always been a source of pain to me, to get the parameters into that s

answered 2011-10-19T13:17:09.763

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