Re: Switch: Case Range Syntax

[Timon Gehr]

On 08/17/2011 07:27 PM, Vijay Nayar wrote:
D adds a very handy feature that allows you to check for a range of
values in a single case.  Is there a particular reason that the syntax
"case<start>:  .. case<end>:" is used instead of treating the case
statement similarly to an array slice, e.g. "case<start>  ..<end>:"?
For example:

import std.stdio;

void main() {
     int bob = 12;
     switch (bob) {
         // Why not "case 0 .. 9:"?
         case 0: .. case 9:
             writeln("Less than 10.");
         case 10: .. case 19:
             writeln("Less than 20.");
         case 20: .. case 29:
             writeln("Less than 30.");
             break;
         default:
             break;
     }
     // Output:  Less than 20.  Less than 30.
}

  - Vijay

With the other syntax, the wrapping switch statement really should look 
like this:

switch(a .. b){
    case x .. y:       // a case statement that matches a range
}

as opposed to:

switch(a){
    case x: .. case y: // a range of case statements
}