I am new to D and have been reading documentation. I had a couple question about
the readLine function. After looking through some of the archive posts I had
seen there were some performance issues using this function, have those been
corrected in the current version?
If not does anyone have any suggestion on how to parse a large file by line, or
better yet with specific character rather than just \n? This is for part of a
larger project I am looking to use D for or I would use perl or something to do
it.

Thanks,
Chris

nilesr@rodsnet.com wrote:
> I am new to D and have been reading documentation. I had a couple question about
> the readLine function. After looking through some of the archive posts I had
> seen there were some performance issues using this function, have those been
> corrected in the current version?
> If not does anyone have any suggestion on how to parse a large file by line, or
> better yet with specific character rather than just \n? This is for part of a
> larger project I am looking to use D for or I would use perl or something to do
> it.
> 
> Thanks,
> Chris

I have a vague memory of the problem in std.stream that you've described, and I think it was fixed quite a while ago.

But if you're looking for more horsepower than what std.stream provides you might check out the mango.io package in Mango (http://www.dsource.org/projects/mango). I haven't tried Mango myself, but many people swear by it.

-- 
jcc7

In article <e0up1s$2e3j$1@digitaldaemon.com>, nilesr@rodsnet.com says...
>
>I am new to D and have been reading documentation. I had a couple question about
>the readLine function. After looking through some of the archive posts I had
>seen there were some performance issues using this function, have those been
>corrected in the current version?
>If not does anyone have any suggestion on how to parse a large file by line, or
>better yet with specific character rather than just \n? This is for part of a
>larger project I am looking to use D for or I would use perl or something to do
>it.
>
>Thanks,
>Chris
>
>

Please post any performance issues you find. I'd guess the posts you refer to
either use unbuffered streams or do not pass a scratch buffer to readLine. I
recommend using the example from the doc as a model
Stream file = new BufferedFile("sample.txt");
foreach(ulong n, char[] line; file) {
stdout.writefln("line %d: %s",n,line);
}
file.close();
the opApply for Stream uses a 128 bytes stack buffer and will only allocate a
temporary buffer from the heap if a line is greater than 128. No memory
allocations happen during that loop in the usual case.

-Ben

BenHinkle wrote:
> Stream file = new BufferedFile("sample.txt");
> foreach(ulong n, char[] line; file) {
> stdout.writefln("line %d: %s",n,line);
> }
> file.close();
> the opApply for Stream uses a 128 bytes stack buffer and will only allocate a
> temporary buffer from the heap if a line is greater than 128. No memory
> allocations happen during that loop in the usual case.

...which also means that you have to .dup the variable 'line' if you plan to use it later. If you only pass a reference to 'line', it's contents will change at the next iteration.

-- 
Niko Korhonen
SW Developer