Re: [sc-users] A bug in switch/case?

["Ph.E" <phe@xxxxxxx>]

Thanks Alberto, for your answer. But can we do anything with 
IdentityDictionary?

For example, the code below works, with switch:

       switch (input,
           "white",        {in = WhiteNoise.ar(inmul, inadd);},
           "pink",        {in = PinkNoise.ar(inmul, inadd);},
           "brown",        {in = BrownNoise.ar(inmul, inadd);},
           "gray",        {in = GrayNoise.ar(inmul, inadd);},
           "clip",        {in = ClipNoise.ar(inmul, inadd);},
           "crackle",    {in = Crackle.ar(param, inmul, inadd);},
           "dust",        {in = Dust.ar(param, inmul, inadd);}
       );

Then, I dug into the SC list, and found this code written by hjh:

c = IdentityDictionary[
 { x == 1 } -> { "case 1".postln },
 { x == 2 } -> { "case 2".postln },
 { x == 3 } -> { "case 3".postln }
];


I tried to write this:

       inputdic = IdentityDictionary [
           {input == "white"}     -> {in = WhiteNoise.ar(inmul, inadd);},
            {input == "pink"}         -> {in = PinkNoise.ar(inmul, 
inadd);},
             {input == "brown"}    -> {in = BrownNoise.ar(inmul, inadd);},
             {input == "gray"}        -> {in = GrayNoise.ar(inmul, 
inadd);},
             {input == "clip"}        -> {in = ClipNoise.ar(inmul, 
inadd);},
             {input == "crackle"}    -> {in = Crackle.ar(param, inmul, 
inadd);},
             {input == "dust"}        -> {in = Dust.ar(param, inmul, 
inadd);}
      ];

But, it doesn't seem to work. I'm just wondering whether my code is 
wrong or there is an impossibility of doing this with 
IdentityDictionary. I should add that input is not a variable but an 
argument of a proto-synthdef function.


Ph.

Alberto de Campo wrote:

> Hi Ph,
>
> > It is possible to use additional switch structures in case there are 
> > more than 7 expressions to be evaluated, but I wonder what is the 
> > advantage of using "case" or "switch" instead of an 
> > IdentityDictionary. ??
>
>
> AFAIR, people wanted to have switch, even against the advice that
> dictionaries are better OOP style and faster. I just measured speed
> again (on a PB G4/1.33 GHz):
>
> (
> var z, cases;
> z = [0, 1, 1.1, 1.3, 1.5, 2, 3, 4, 5];
> cases = [ 1, { \no },
> 1.1, { \wrong },
> 1.3, { \wrong },
> 1.5, { \wrong },
> 2, { \wrong },
> 0, { \true },
> 3, { \true }
> ];
> )
> {
> 100000.do {
>     z.choose.switch (*cases);
> }
> }.bench;
> )
>
> -> ca 1.4 to 1.75 sec.
>
> (
> var z, cases;
> z = [0, 1, 1.1, 1.3, 1.5, 2, 3];
> cases = IdentityDictionary[
>     1 -> { \no },
>     1.1 -> { \wrong },
>     1.3 -> { \wrong },
>     1.5 -> { \wrong },
>     2 -> { \wrong },
>     0 -> { \true },
>     3 -> { \true }
> ];
>
> {
> 100000.do {
>     cases[z.choose].value;
> }
> }.bench;
> )
>
> -> ca 0.33 to 0.45 sec, and the same
> same with Event instead of IdentityDictionary.
>
> best,
> adc