Library vs Framework (was Dr. Dobb's Python-URL!)

[Rocco Moretti]

Simon Brunning wrote:
> On 8/15/05, Terry Hancock <hancock at anansispaceworks.com> wrote:
> 
>>On Monday 15 August 2005 09:54 am, Simon Brunning wrote:
>>
>>>If you call its code, it's a library. If it calls yours, it's a framework.
>>
>>Such concision deserves applause. ;-)
> 
> 
> Thank you. ;-)
> 
> As others have pointed out, this is a *drastic* simplification,
> perhaps an oversimplification. You will inevitably need to call a
> framework's code in addition to it calling yours, and a callback
> argument or two won't turn a library into a framework. But I think it
> captures the essence of the difference.

The point that passed me by the first time, and which Magnus et al. 
helped me realize, is that it's referring not to an instantaneous, 
mechanical view of calling, but to a more general, philosophical view of 
calling.

With a library, the user's code is "in charge" of the program structure, 
and calls the library to fill in the details and help out. With a 
framework, the framework is "in charge", and the user code is filling in 
with a supporting role. With this in mind, it's easy to see why Andy 
Smith feels frameworks are restricting - after all, it's the framework, 
not the user, who is "in charge" of program structure.

But I'm not sure if library vs. framework a fair comparison - the two 
are doing different things. With a framework, you're not really writing 
your own program, you're customizing someone else's. Sort of a vastly 
more flexible version of command line options. Saying you can't reuse 
code written for a framework is kind of like saying that it's difficult 
to use an Apache config file with the Gimp.