Improvement to switch-case statement

[Daniel Keep]

Michel Fortin wrote:
> On 2008-12-31 18:22:32 -0500, "Adam D. Ruppe" 
> <destructionator at gmail.com> said:
> 
>> This wouldn't be any less efficient than any other switch statement; 
>> writing
>>
>> case 2..5:
>>   code;
>>   break;
>>
>> could just be magically converted into
>>
>> case 2:
>> case 3:
>> case 4:
>> case 5:
>>   code;
>>   break;
> 
> Except that if you want to keep consistency with array slices, 2..5 
> should probably not include 5 in the range, thus should be equivalent 
> "case 2,3,4". Unfortunatly, that's generally not what you want when 
> creating such cases. Imagine writting:
> 
>     case 'a'..'{':
>     case 'A'..'[':
> 
> Concistent, yes; but not very appealing. What you want to be able to 
> write is this:
> 
>     case 'a'..'z':
>     case 'A'..'Z':
> 
> But then it doesn't work as elsewhere in the language anymore.
> 

Python solves this rather elegantly; instead of

   if( chr in 2..5 ) ...

you can just do this:

   if( 2 <= chr <= 5 ) ...

which allows you to explicitly control which ends are inclusive/exclusive.

   -- Daniel