[PD] Purpose of sig~

Jonathan Wilkes jancsika at yahoo.com
Wed Nov 3 23:42:07 CET 2010



--- On Wed, 11/3/10, Andy Farnell <padawan12 at obiwannabe.co.uk> wrote:

> From: Andy Farnell <padawan12 at obiwannabe.co.uk>
> Subject: Re: [PD] Purpose of sig~
> To: pd-list at iem.at
> Date: Wednesday, November 3, 2010, 5:14 PM
> There are some uses of [sig~] which
> are not immediately
> obvious but turn out to be desirable. By definition it
> is useful any place you want a message domain value
> converted
> to a signal, without any further ado. Without it, relying
> only on implicit conversion you might never have access to
> a signal except by a degenerate idiom like
> 
> [$1(
> |
> [line~]
> 
> 
> Crucially, [sig~] can be given a creation parameter, as in
> [sig~ 1], and will not need any messy initialisation 
> like using a [loadbang] in order to obtain a signal 
> constant immediately. 
> 
> Why might you want a signal constant? Perhaps for
> a relation like (1 - x), useful in panning, crossfading,
> or (1 / x) common in waveshaping.
> 
> Matju raises a question over DSP on/off. I have
> encountered
> problems relying on implicit right inlet conversion 
> with deep abstractions, so from practical experience 
> it seems safer to use [sig~] in these circumsatnces.

Is this because signal inlets of signal objects (except for the 
leftmost) don't accept one-element lists?  If so I think it'd be 
a cheaper workaround putting a [t f] before those inlets.

> 
> It also make code more readable to make important
> message/signal distinctions explicit.
> 

They are already explicit-- at least in pd-extended, where the 
signal inlets are visually distinct from the control inlets.

-Jonathan


      



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