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[Andrei Alexandrescu]

Denis Koroskin wrote:
> On Fri, 10 Oct 2008 19:19:45 +0400, Sergey Gromov 
> <snake.scaly at gmail.com> wrote:
> 
>> Fri, 10 Oct 2008 19:10:19 +0400,
>> Denis Koroskin wrote:
>>> On Fri, 10 Oct 2008 18:33:43 +0400, Andrei Alexandrescu
>>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>
>>> > Sergey Gromov wrote:
>>> >> I'd also like
>>> >>   "foo" ~ text ~ "bar"
>>> >> to become something like
>>> >>   (new Array!(char)) ~= "foo" ~= text ~= "bar"
>>> >> that is what Java does to string concatenation.  Sugar doesn't 
>>> seem to
>>> >> couple well with a purely library type.
>>>
>>> I doubt that. Java strings are immutable, their length can't be changed
>>> either (i.e. they are a direct analog of a proposed invariant(char)[]).
>>> Concatanating Java strings don't turn them into array, and it is dead
>>> slow. Every sane person uses StringBuilder instead.
>>
>> Java compiler substitutes
>>
>> "foo" + text + "bar"
>>
>> with
>>
>> new StringBuilder().append("foo").append(text).append("bar").toString()
>>
>> all by itself because both String and StringBuilder are built-in
>> classes.
> 
> Yes, you are right. From The Java Language Specification, 3rd edition:
> 
>> To increase the performance of repeated string concatenation,
>> a Java compiler may use the StringBuffer class or a similar technique
>> to reduce the number of intermediate String objects that are created
>> by evaluation of an expression.

But that doesn't require StringBuffer to be part of the language. With 
literals, the compiler can do whatever magic it wants.

Andrei