Design of intuitive interfaces

[Ary Borenszweig]

KennyTM~ wrote:
> On Feb 22, 10 06:07, Ary Borenszweig wrote:
>> Michel Fortin wrote:
>>> On 2010-02-21 10:19:06 -0500, bearophile <bearophileHUGS at lycos.com> 
>>> said:
>>>
>>>> Michel Fortin:
>>>>> array.sort(predicate) // sort in place using predicate
>>>>> array.sorted(predicate) // create sorted copy using predicate
>>>>> array.isSorted(predicate) // tell if the array is sorted using
>>>>> predicate
>>>>
>>>> Good.
>>>>
>>>> Another possibility is to let D2 accept ? and ! too inside variable
>>>> names, so they can become (as in Ruby I think, and something similar
>>>> is common in Lisp-like languages too):
>>>> array.sort(predicate)
>>>> array.sort!(predicate); // void function
>>>> array.sorted?(predicate)
>>>
>>> Note that Ruby only accept this as a suffix, but yeah it's part of the
>>> identifier.
>>>
>>> And I'd love this, but the ! suffix is totally ambiguous with the
>>> template instantiation syntax, and the ? suffix would be ambiguous in
>>> the ternary operator "?:".
>>
>> But ruby has the ternary operator "?:", it just gives the "?" in the
>> identifier more precedence.
>>
>> So there's just the backwards compatibility problem, but if you had:
>>
>> foo? something : something_else
>>
>> then now it won't compile ("foo?" can't be found) and you'll have to
>> change it to
>>
>> foo ? something : something_else
>>
>> so it's a safe backwards incompatible change.
> 
> enum foo = false;
> enum bar = 2;
> ...
>   case foo?(1):bar: break;
> 
> Suddenly, if "foo?" is defined, the value of the case completely changed 
> and you've got a "bar" label.

Cases are known at compile-time.