Performance improvements for D / DMD compiler.

[Bill Baxter]

Walter Bright wrote:
> Bill Baxter wrote:
>> The question is how can we write functions in D that take big structs 
>> as parameters in such a way that it is:
>> A) efficient and
>> B) guaranteed not to change the caller's value
>>
>> In C++ the answer is const LargeStruct&.
> 
> C++ doesn't *guarantee* it won't change. There are at least two legal 
> ways to do it.

Very true.  What I'm after is really a concise way to both
a) document to readers of the code that it won't change and
b) get the compiler to zap me if I accidentally try to modify it.

>> In D the answer is...
> 
> There aren't const references in D. But the 3 ways to pass it by pointer 
> are:
> 
> 1) inout
> 2) take the address and use a pointer
> 3) make it a class instead

And none of those accomplishes a or b.

--bb