Thanks, Claude! I'm working on moving your example into the Vivid context.
Tom, indeed, that would be simpler! I wanted to use `toI`. But I don't see
how to do that without hard-coding every choice of which parameter to send
a message to.
For instance, suppose you've got a list of parameter names `["freq","amp"
..]` from which you want the code to choose a parameter `p` randomly every
cycle, and set it to the value `x`. You can't write `set s (x :: I p)`,
because the `p` in `I p` is a type-level variable rather than an ordinary
one.
I considered keeping a list of functions `[setFreq, setAmp ..]` instead of
a list of parameter names, but I haven't found how to represent such a list:
.
> :set -XDataKinds
> :set -XRankNTypes
> s <- synth boop ()
> [set s (3::I "amp"), set s (5::I "freq")]
<interactive>:194:22: error:
• Could not deduce: Elem "freq" '[] arising from a use of ‘set’
from the context: VividAction m
bound by the inferred type of it :: VividAction m => [m ()]
at <interactive>:194:1-41
• In the expression: set s (5 :: I "freq")
In the expression: [set s (3 :: I "amp"), set s (5 :: I "freq")]
In an equation for ‘it’:
it = [set s (3 :: I "amp"), set s (5 :: I "freq")]
>
On Wed, Jul 4, 2018 at 11:50 AM <amindfv_at_gmail.com> wrote:
> The approach I'd use might be a little different. Vivid offers a "toI"
> function which takes any number and converts it to an "I".
>
> So for example:
>
> ```
> myNums = [1..10] :: [Double]
>
> sd0 = undefined :: SynthDef '["freq"]
> sd1 = undefined :: SynthDef '["amp"]
>
> main = do
> s0 <- synth sd0
> s1 <- synth sd1
> forM_ myNums $ \n -> do
> set s0 (toI n :: I "freq")
> set s1 (toI n :: I "amp")
> ```
>
> Also: "toI" works on any numeric type (any "Real n"), and "I" itself is a
> numeric type. So you can always write:
>
> x = 5 :: I "freq"
> y = toI x :: I "amp"
>
> Tom
>
>
> El 4 jul 2018, a las 08:30, Jeffrey Brown <jeffbrown.the_at_gmail.com>
> escribió:
>
> Composers reuse melodic material across different instruments. I would
> like to do that in Vivid. I would keep a sequence of values and send it
> sometimes to one parameter of one synth, sometimes to a different parameter
> of a different synth.
>
> To do that I would have to coerce those numbers to values of type `I a`,
> where the string `a` is known only at runtime. I tried to write a function
> to do that:
>
> import GHC.TypeLits
> toIOf :: (Real n, GHC.TypeLits.KnownSymbol a) => String -> n -> I a
> toIOf "freq" n = toI n :: I "freq"
> toIOf "amp" n = toI n :: I "amp"
>
> but it won't compile, because the outputs of `toIOf "freq"` and `toIOf
> "amp"` have different types.
>
> Is this possible?
>
> --
> Jeff Brown | Jeffrey Benjamin Brown
> Website <https://msu.edu/~brown202/> | Facebook
> <https://www.facebook.com/mejeff.younotjeff> | LinkedIn
> <https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often
> miss messages here) | Github <https://github.com/jeffreybenjaminbrown>
>
>
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--
Jeff Brown | Jeffrey Benjamin Brown
Website <https://msu.edu/~brown202/> | Facebook
<https://www.facebook.com/mejeff.younotjeff> | LinkedIn
<https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often miss
messages here) | Github <https://github.com/jeffreybenjaminbrown>
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Received on Thu Jul 05 2018 - 02:32:27 BST