Add c like switch (fallthrough tag)?

[Andersama]

New to the language. I started reading the documentation and then looking at the source code for the compiler. It seems like it'd be relatively straightforward to have a c-like switch if there isn't one already. Seeing how #partial looks like it ignores unhandled cases, I'm thinking a #fallthrough tag or switch fallthrough. In the event someone wants fallthrough behavior by default. A tag appears to be far easier to do.

To be fair most of the code I've put in switch blocks doesn't use fallthroughs, but every once in a while it just makes sense. While I'm incredibly used to ()'s being everywhere I do like the different variations of for and switch statements. I'm not exactly invested in the language, but since it seems like it's designed with as few keystrokes in mind, I think someone might like this.

// if for example you wanted to write a particular device
#fallthrough switch x%8 {
case 0: //do no thing
case 1: do_thing()
case 2: do_thing()
case 3: do_thing()
// and so on...
}

Relevant area in the parser for anyone who'd want to add it as a tag:

Odin/src/parser.cpp

Line 4689 in 7b539e3

} else if (tag == "partial") {

I might build the compiler myself and see if I can't work out how to do this for fun.

[Kelimion]

You can write that as either:

switch n {
case 0: //do no thing
case 1, 2, 3: do_thing()
}

Or:

switch n {
case 0: //do no thing
case 1: fallthrough
case 2: fallthrough
case 3: do_thing()
}

[Kelimion]

Then only 0 and 3 would ever be hit, with any other value ignored.

[Andersama]

Hold on, shouldn't your second example have been

switch n {
case 0: //do no thing
case 1: do_thing()
    fallthrough
case 2: do_thing()
    fallthrough
case 3: do_thing()
}

?
Now I might just have to play around with odin to figure out what's going on. I don't understand the syntax.

[Kelimion]

Hold on, shouldn't your second example have been

switch n {
case 0: //do no thing
case 1: do_thing()
    fallthrough
case 2: do_thing()
    fallthrough
case 3: do_thing()
}

? Now I might just have to play around with odin to figure out what's going on. I don't understand the syntax.

No, because then do_thing would be called 3 times if n == 1, twice if n == 2, and once if n == 3. In my 2nd example it calls do_thing once if n is one of 1, 2 or 3.

[Andersama]

Sorry forgot to get back to this, I might've screwed up the first example so it wasn't quite clear (I probably should've had case 0: do_thing()). That was the intended effect of the original example.

[Kelimion]

Duff's Device?