[PD] pdmtl abstractions questions and comments (previously without a subject)

Thomas O Fredericks tof at danslchamp.org
Wed Jul 4 21:24:53 CEST 2007


> > b) abstractions that finish with "_" are graphical abstractions.
> > Sometimes, we create an abstraction without a gui, then we create a
> > gui that wraps the same abstraction. The name of both abstractions
> > will be the same, except that the second version will have a "_"
> > appended.
>
> This sounds to me that you are exposing the implementation in the
> interface.  The interface should be defined separately from the
> implementation, and definitely does not need to reflect it.  When
> using an object, it is a distraction to think about the
> implementation of that object.  Instead the programmer should be
> thinking about the implementation of the program that is being
> built.  Therefore, the programmer would only need to know about the
> interface.

I do not understand your comment, but here are more details on how
this works: a pdmtl abstraction whose name ends with a "_" (or a "_~")
is usually exactly the same abstraction as one that has the same name
but does not end with a "_" (or  "_~"). For the programmer, there is
no difference between the inlets or outlets of both versions. The only
difference is that in one version, the abstraction is a Graph On
Parent that displays on screen controls, while the other does not.
Usually when I am programming, I will use the nice and convenient "_"
(GOP) version. But, since we all know Pd's graphic engine is real
slow,  when it is time to set up an installation or do a performance
or when I generate the abstractions dynamically , I will switch the
abstractions to the non GOP version WITHOUT hurting in any way the
interconnection between all the objects. Also, since the "_"
abstractions simply wrap their counterparts, they are both
automatically updated if the "engine" is updated.

Tom




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