John Carmack on Eclipse performance

[deadalnix]

On Sunday, 6 October 2013 at 16:02:24 UTC, Joseph Rushton 
Wakeling wrote:
> On 05/10/13 01:55, deadalnix wrote:
>> D has some really serious flaw when it come to functionnal 
>> style.
>
> Really?  That's a shame. :-(
>
>>  - Function aren't first class.
>>  - Delegates break type system.
>>  - Immutable object have identity issue that wouldn't show up 
>> in a functional
>> language. It is unsure what the semantic around them is (and 
>> if identity must be
>> preserved, then functional style is badly impaired).
>>  - Many qualifier do start to not make any sense when using 
>> functions as
>> arguments (inout for instance).
>>  - Expect for type qualifier, it is impossible to express 
>> return qualification
>> depending on the input(s qualification (and see point above, 
>> that do not work
>> when using first class functions/delegates).
>>
>> On implementation side, heap allocated values aren't optimized 
>> to go on the
>> stack, ever. And the GC is unable to take advantage of 
>> immutability. Note that
>> because everything is immutable in functional programming, 
>> both are mandatory if
>> you don't want to trash your performances.
>
> How much of this is actually a language problem (I imagine the 
> first-class functions and delegate issues are) and how much is 
> to do with implementation?

What comes before "On implementation side" is language problem. 
What comes after is implementation problem.