[PD] message-creation and parsing questions

Hans-Christoph Steiner hans at eds.org
Thu Jun 12 05:37:43 CEST 2003

> On Tuesday, June 10, 2003, at 11:03  pm, David Merrill wrote:
>> Hello pd-ers,
>> I'm still getting the hang of pd, and I'm currently using it to build 
>> the mechanism to run a perceptual experiment.  For each condition I 
>> want to read in values from a text file, play a tone, and record the 
>> result. The parts I'm having trouble with are:
>> - how can I build up a message from parts?  for instance, the 
>> [writesf~] object responds to an "open" message with a single 
>> argument, like:
>> "open /tmp/output1.wav"
>> but I want to be able to iterate, and supply "output2.wav", 
>> "output3.wav" etc..  I have looked at the docs for the [pack] object, 
>> but I'm not sure that it can receive messages as input and pack them, 
>> or output it's result as a message - is that correct?  am I thinking 
>> about this in a wrong way?
[makefilename output%s.wav]----[open $1(----[writesf~]

>> - how can I parse a line of text such as: "output1.wav 440 500 1500" 
>> that I get from a [textfile] [bang] into its constituent parts 
>> (preserving the appropriate types)?

[unpack] or [route] depending on what you want to do.

>> - (related to the above) is parsing a string different from parsing a 
>> list?

Yes, you use different objects.  For list parsing you can use [pack], 
[unpack], [route], etc.  There are some objects for parsing symbols 
(what strings are called in pd) but I don't know them off hand.  Also, 
there is a python object and a tcl object, so those could be handy for 


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