Re: [sc-users] BooleanUGens (was Re: conditional statement in SynthDef)

[Scott Wilson <sdwilson@xxxxxxxxxxxx>]

On 6 Sep 2005, at 08:10, Dan Stowell wrote:

> 2005/9/6, Joshua Parmenter <joshpar@xxxxxxx>:
> > On Sep 5, 2005, at 1:22 PM, James Harkins wrote:
> >
> > > Since BinaryOpUGen already supports == and != I think it could just 
> > > be
> > > documented how to write the BinaryOpUGen yourself
> > I think this makes sense...
>
> I'm afraid I don't quite understand. Could someone spell it out for a
> stupid person, please? The situation as I see it is that there already
> exist BinaryOpUGens which perform equality/non-equality tests, but for
> some reason these aren't automatically inserted when someone uses "=="
> or "!=" in a SynthDef. What's the reason? Josh found he couldn't
> compile this in without breaking things so it's an unavoidable
> problem?

The problem is that == in its traditional non-UGen sense is used in 
tests when constructing a BinaryOpUGen which optimise out degenerate 
cases such as aUGen * 0.0 where the second operand is a constant. In 
this case you don't get a UGen, you get a constant of 0.0, thus saving 
some computation.
> When you say "documented how to write the BinaryOpUGen yourself", does
> that mean documenting how to manually rewrite "==" and "!=" within
> SynthDefs?

You can still make a BinaryOpUGen directly like so:

BinaryOpUGen('==', someUGen, anotherUGen);

S.