[Audacity-nyquist] extreme newbie question about abs function

[Jeff R. <jef...@ya...>]

I am an absolute beginner with Nyquist. I am trying to understand why this
does not work:

1. Select some audio in Audacity.
2. Effects -> nyquist prompt.
3. enter:

    (abs s)

4. expect that each sample in the selection should change to its absolute
value.

Instead, Audacity says "Nyquist did not return audio".

I'm sure that there is just some very basic hole in my understanding how
Nyquist and how it works in Audacity. Even the slightest clue-in would be helpful.

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