Why Ruby?

[Andrei Alexandrescu]

On 12/19/10 11:21 AM, foobar wrote:
> Andrei Alexandrescu Wrote:
>
>> On 12/19/10 5:08 AM, foobar wrote:
>>> Walter Bright Wrote:
>>>
>>>> JRM wrote:
>>>>> you could write:
>>>>> sort!(@1>@2)(x);
>>>> [...]
>>>>> I think this idea (or something similar) is worth consideration.  It is
>>>>> simply a small extension to an already existing feature that would give D
>>>>> a terser syntax for lambda's than most of the other languages we've been
>>>>> discussing.
>>>>
>>>> but:
>>>>
>>>>       sort!("a>b")(x);
>>>>
>>>> is just as short! And it already works.
>>>
>>> I think that the issue here is not about syntax as much as it is about semantics:
>>> As others said, this is equivalent to dynamic language's eval() or to D's string mixin and the this raises the question of hygiene which sadly has no good solution in D.
>>>
>>> The main concern is this:
>>> In what context are the symbols 'a' and 'b' evaluated?
>>>
>>> At the moment they cannot be correctly evaluated at the caller context and do not allow:
>>> sort!("a.foo()>   b.bar()")(whatever);
>>
>> That does work. What doesn't work is calling nonmember functions looked
>> up in the context of the caller.
>>
>> Andrei
>
> Either way, I personally don't care that much for another syntax for delegates. I personally just want to see this ugly hack removed from the standard library and discouraged. This feature promotes a code smell. And for what, as you said yourself, to save 4 characters?

"a > b" vs. (a, b) { return a > b; }

Savings: 17 characters.

> D should be consistent with only ONE delegate syntax. This is why Ruby reads like poetry to its followers and c++ is like carving letters in stone.

Also, Ruby is well slower than C++ and other languages. It's easy to 
design a beautiful language if that's the primary concern. It's 
difficult to design a language when you want to keep in harmony a larger 
list of desiderata.

> I much prefer that the lowering you mentioned to be implemented so that performance wise this UGLY hack will have no benefits.

The lowering will unfortunately solve little. I don't see how

sort!"a > b"(array);

is horrible but

sort(a, b; array) { return a > b; }

is beautiful and clear. Besides, that return is bizarre - did you mean 
return from the comparison or the caller? Ruby chose the latter, which I 
think is very sensible, but in that case you have a more difficult time 
returning locally. Of course, inventing new syntax is always available :o).

> regarding hygiene - the term was correct.

No.


Andrei