Re: Should the 2.054 feature about warning on implicit fallthrough

[Timon Gehr]

On 09/15/2011 12:43 AM, bearophile wrote:

Timon Gehr:

What would you suggest?

At the moment I suggest nothing, because the situation is set.

Case syntax was discussed a lot, by me too. I suggested to differentiate the syntax, not 
using ".." because in D they denote an interval open on the right.

'C switch' means 'jump table'. It does do that perfectly. ;)

C language is full of badly designed parts :-)

What is your point?

Well, I don't understand the error it gives :-) Are you able to explain it to 
me?


import std.stdio;
void main() {
      int i = 1;
      switch(i) {
          case 0:
              writeln("case 0");
              goto default; // needed here
          aLabel:
              writeln("a label");
          default:
              writeln("default");
              // But always falls through here
      }
}

test.d(10): Error: switch case fallthrough - use 'goto default;' if intended

Bye,
bearophile

import std.stdio;
void main() {
     int i = 1;
     switch(i) {
         case 0:
             writeln("case 0");
             // goto default; // NOT needed here (for it to compile)
         aLabel:
             writeln("a label");
             goto default; // explicit fall through
         default:
             writeln("default");
             // But always falls through here
     }
}

And that is exactly the same as this:


import std.stdio;
void main() {
     int i = 1;
     switch(i) {
         case 0:
             writeln("case 0");
             writeln("a label");
             goto default; // comment this out to get your error back.
         default:
             writeln("default");
     }
}


It is a simple case of switch case fallthrough.