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

[Alberto de Campo <adc@xxxxxx>]

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
--
--
Alberto de Campo
Bergstrasse 59/33
A-8020 Graz, Austria
e-mail : decampo@xxxxxx
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