[PD] definitions of data types

Frank Barknecht fbar at footils.org
Wed Feb 8 01:32:53 CET 2006


Hallo,
Martin Peach hat gesagt: // Martin Peach wrote:

> OK I see, so then wouldn't it be a good idea to merge those two types of 
> list into one? Just treat all messages as lists. Then there is no 
> restriction on the first element.
> Then an external could have a single list method which would be called 
> for any possible input, instead of the plethora of methods for each 
> possible input symbol and type the way it is now; the external would 
> parse its input and call all those functions itself instead of 
> registering them all with pd and having pd call them. Probably the time 
> taken would be no different and the symbol table would be much smaller.

Let me quote Matju on this (from a post he did on pd-dev replying to Hans,
when the term "undefined set" was still debated and finally abandoned and
which I called "meta-messages".)

  Messages have selectors. Selectors are used to select methods. 
  
  Suppose that the Pd of your dreams comes to existence, and that may mean
  without any so-called "undefined sets". Every message would be a "list".
  Then how would you send a message like "set $1" or "color $1 $2" to an
  object?  somehow the list method (which is then the only method in each
  class) would have to deal with all messages. Then a neat idea to break
  down the code in more manageable bits would be to select one of several C
  functions depending on the first element of the received list. This first
  argument could be called a "selector". But now, what about a
  list-processing object that really needs to be able to receive a list in
  the same inlet as you would use to do "set" and "color" and such? To
  disambiguate this, let's prefix the lists intended for list-processing
  with a special selector that we might call "list".  
  
  Thus messages would be called lists and former lists would be called
  something else like "really lists" but there might be better names.  And
  then again there would be things that are lists but not "really lists"
  and there appear again the "undefined sets" that aren't undefined nor
  sets.

Or in the words of Miller: 

  It's not clear whether this was a good design choice, but it's
  entrenched.

I learned the word "entrenched" from that.

Ciao
-- 
 Frank Barknecht                 _ ______footils.org_ __goto10.org__




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