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Re: Why callbacks?

by exussum0 (Vicar)
on Mar 30, 2007 at 17:51 UTC ( #607553=note: print w/ replies, xml ) Need Help??


in reply to Why callbacks?

Callbacks are great for injecting behaviour into something - ruby calls them mixins.

Instead of having variables referenced within the function, outward, to something lexically scoped or globally is really weird. I would expect the callback retaining the data and you querying it for the result. Hrm..


Comment on Re: Why callbacks?
Re^2: Why callbacks?
by Joost (Canon) on Mar 30, 2007 at 17:56 UTC
      Right right, was using the wrong terminology for what i meant. tnx.

        Terminology is important, as those are commonly agreed protocols. Ialize that this is not just a problem with Vicar, even other higher type of saints make those mistakes, for example ovid calls a common class a framework.

        Regardless, aimminghigh and use terminologies properly.

      You can do mixins in Perl as well, by using Exporter to import methods into an OO class. CGI::Application uses this technique to add methods via plugins.
Re^2: Why callbacks?
by Cop on Dec 23, 2007 at 19:42 UTC

    Obviously you are looking at this as a coder, not a language designer. There are two purposes (actually only one since those two are one if you can see): 1) Dynamically change or determine the behavior; 2) make it possible for creation of frameworks.

    For example, in a GUI program with callback, rendering engine no longer needs to know how to render a component, the component knows and in way renders itself.

    This might seem abit diificult for you to understand, but try your best to learn.

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