Haskell

[Timon Gehr]

On 08/25/2011 02:34 AM, Jonathan M Davis wrote:
> On Wednesday, August 24, 2011 17:17 Timon Gehr wrote:
>> On 08/25/2011 01:15 AM, Timon Gehr wrote:
>>> On 08/24/2011 11:55 PM, bearophile wrote:
>>>> Timon Gehr:
>>>>> If anyone is interested:
>>>>> http://pastebin.com/2rEdx0RD
>>>>
>>>> I suggest you to usually compile your D code with -w, I see some
>>>> missing overrides. At line 40 it gives me a "Warning: statement is not
>>>> reachable".
>>>
>>> There is only one missing override, but it is reported for every
>>> instantiation of the template. Statement at line 40 is necessary to make
>>> the /type inference/ work out, and such things are the reason I don't
>>> usually turn warnings on. Another example where warnings are a pita:
>>>
>>> case "bla","blu","blo": // Warning: fallthrough
>>> case "xxx","yyy","zzz":
>>>
>>> What the code expresses is: There are two cases, one occurs if the input
>>> is bla blu or blo, and the other one if it is xxx or yyy or zzz. Those
>>> cases should be handled the same way. (At least for now).
>>> goto case; is both unnecessary and ugly in that case.
>>>
>>> So basically, for me there are too many false positives to make the -w
>>> switch really practical, which is a pity, as they would have catched the
>>> missing override in this case.
>>>
>>>> Are you able to use it to translate the Haskell version of this task?
>>>> http://rosettacode.org/wiki/Hamming_numbers#Haskell
>>>
>>> Challenge accepted.
>>
>> ASDF. I got it working quite fast, and then I started a fight with
>> std.bigint.BigInt.toString until I accidentally cp'd over my source
>> code. That will be reported soon, it makes BigInt UNUSABLE.
>>
>> I am going to code it again...
>
> Don refuses to implement it, because it always creates a new string. He wants
> something like the DIP for writeFrom (or whatever the exact function name was)
> which allows for writing to a pre-existing buffer. I think that there's
> already a bug on the issue, but I'd have to search for it.
>
> - Jonathan M Davis

We must just add _*RVO for arrays*_ to the compiler and then users can 
use the built-in array concatenation syntax for the efficient thing. 
Everything else would just waste the precious grammar rules.
How it is now is just painful and it does not fit well into the rest of 
Phobos. Not even std.conv.to can convert a BigInt to a string. This is a 
trivial issue that renders std.bigint unusable for these kinds of little 
scripts, where they actually would be of use. I don't care if I get a 
newly allocated string, because I only convert it once to output it. The 
current design just hurts me everywhere, and wasted a lot of my time. 
Premature optimization is the root of all evil.