General Category > Ideas

Switch proposal

<< < (2/3) > >>

lerno:
So, current options:

(A) case 3 | for empty fallthrough, explicit fallthrough when it is non empty.
(B) | case 3 to indicate the previous case was fallthrough, regardless whether it was empty or not.
(C) case 3, for empty fallthrough, explicit fallthrough when it is non empty.

Types of "fallthrough" keyword:

(a) fallthrough
(b) goto next
(c) goto case
(d) goto case 4
(e) continue case
(f) next
(g) nextcase

bas:
Wow, that's a lot of posts in one day..

The case of
--- Code: ---case 3|
--- End code ---
looks quite nice, but it differs from the case where you have some code, but also a fall-through.
I want to simplify the language as much as possible, so I don't really want to change the current behavior too much. If you think
about the possible bugs that often occur is only that a develop forgets to add the break keyword. So the only needed option I
think is to add the fallthrough keyword and require that for all fallthroughs. So for example:


--- Code: ---case 1:
   break;
case 2:
   fallthrough;
case 3:
   fallthrough:
default:
   // ...

--- End code ---

or maybe even allow empty cases to fallthrough without keyword to make code with lots of fallthrough's better readable


--- Code: ---case 1:
   break;
case 2:  // allowed because empty case
case 3:
   fallthrough;
default:
   // ..

--- End code ---

lerno:
I think fallthrough automatically on empty is very inconsistent. Consider this, with impllcit break:


--- Code: ---func void printTest(i32 foo) {
 switch (foo) {
   case 1:
     printf("A\n");
   case 2:
     printf("B\n");
   default:
     // Do nothing
  }
}
printTest(1);

--- End code ---

Prints "A"

Now we decide to comment out printf("A\n");


--- Code: ---func void printTest(i32 foo) {
 switch (foo) {
   case 1:
     // printf("A\n");
   case 2:
     printf("B\n");
   default:
     // Do nothing
  }
}
printTest(1);

--- End code ---

Now this prints "B". Perhaps not what we expected... So I think case 1, is a better suggestion for empty fallthrough (version C)

bas:
Fallthrough is always automatic, except when you use break. So there is never an automatic break.
The compiler gives gives a warning/error if you don't use break/fallthrough in cases there is a code..

lerno:
Err... My proposal was to add implicit break.

Navigation

[0] Message Index

[#] Next page

[*] Previous page