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digitalmars.D - 2/3 dimensional arrays + comparison page truncated

reply Dan <twinbee41 skytopia.com> writes:
A few things. Firstly, what's happened to the main comparison page:
http://www.digitalmars.com/d/comparison.html

It's only showing stats for D.

Second thing. How does D allocate for a 2D (or even 3D) array. I tried to look
everywhere on the D site for this, and nothing came up. I'm just curious to how
it compares with the long-winded C/C++ way of using malloc to create arrays.

Lastly, is there a place which shows all of the D commands with a short
description? What would be great too is if they were all sorted by how often
each command is used.
Aug 05 2007
next sibling parent reply Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:
Dan wrote:

 A few things. Firstly, what's happened to the main comparison page:
 http://www.digitalmars.com/d/comparison.html
 
 It's only showing stats for D.


Hm.  Dunno.


 Second thing. How does D allocate for a 2D (or even 3D) array. I tried to look
everywhere on the D site for this, and nothing came up. I'm just curious to how
it compares with the long-winded C/C++ way of using malloc to create arrays.


Well... it sorta depends.  For static/fixed-length arrays:
int[5][10] foo;
x = foo[2][3];

Its the same as this:
int[50] foo;
x = foo[(2 * 10) + 3];

At least in terms of memory layout.  The difference is in how it 
interacts with slices, typeinfo, and the meaning of the .length property.

Dynamic/variable-length arrays, on the other hand, are structures of a 
length and pointer to heap memory.  So its best to say there /are no/ 
multi-dimensional dynamic arrays -- but there /are/ arrays whose element 
type is itself an array.  A subtle difference.



 Lastly, is there a place which shows all of the D commands with a short
description? What would be great too is if they were all sorted by how often
each command is used.


Someone was maintaining a D keyword glossary at one time, and might 
still be, but I be darned if I can remember a link to it.  -_- 
Hopefully someone else has it bookmarked.

-- Chris Nicholson-Sauls
Aug 06 2007
parent reply Kirk McDonald <kirklin.mcdonald gmail.com> writes:
Chris Nicholson-Sauls wrote:

 Someone was maintaining a D keyword glossary at one time, and might 
 still be, but I be darned if I can remember a link to it.  -_- Hopefully 
 someone else has it bookmarked.


That would be me, and I still am. :-)

As Deewiant mentioned, it's on Wiki4D, but that site is down. The Google 
cache is slightly out of date (it is missing __traits), but still 
serviceable.

-- 
Kirk McDonald
http://kirkmcdonald.blogspot.com
Pyd: Connecting D and Python
http://pyd.dsource.org
Aug 06 2007
next sibling parent Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:
Kirk McDonald wrote:

 Chris Nicholson-Sauls wrote:

 Someone was maintaining a D keyword glossary at one time, and might 
 still be, but I be darned if I can remember a link to it.  -_- 
 Hopefully someone else has it bookmarked.


 
 That would be me, and I still am. :-)
 
 As Deewiant mentioned, it's on Wiki4D, but that site is down. The Google 
 cache is slightly out of date (it is missing __traits), but still 
 serviceable.
 


And I'm off to bookmark the link anyhow, so I /will/ have it next time 
it comes up.  :)  Thanks for doing that, by the way, even if I haven't 
used it often.

-- Chris Nicholson-Sauls
Aug 06 2007
prev sibling parent Chad J <gamerChad _spamIsBad_gmail.com> writes:
Kirk McDonald wrote:

 Chris Nicholson-Sauls wrote:

 Someone was maintaining a D keyword glossary at one time, and might 
 still be, but I be darned if I can remember a link to it.  -_- 
 Hopefully someone else has it bookmarked.


 
 That would be me, and I still am. :-)
 
 As Deewiant mentioned, it's on Wiki4D, but that site is down. The Google 
 cache is slightly out of date (it is missing __traits), but still 
 serviceable.
 


I did not know that existed.  That actually sounds very useful, 
especially for showing newbies how to use D.

I learned most of that by cross-referencing the NG with the digital mars 
site and with simple compiler tests.  But that's the slow way ;)

Thanks for making such a glossary.
Aug 06 2007
prev sibling next sibling parent reply Deewiant <deewiant.doesnotlike.spam gmail.com> writes:
Dan wrote:

 A few things. Firstly, what's happened to the main comparison page: 
 http://www.digitalmars.com/d/comparison.html
 
 It's only showing stats for D.


It got tonnes of complaints by non-D users about how their languages were being
misrepresented. In the end, it was decided to take them out completely.


 Lastly, is there a place which shows all of the D commands with a short
 description? What would be great too is if they were all sorted by how often
 each command is used.


http://www.prowiki.org/wiki4d/wiki.cgi?LanguageSpecification/KeywordIndex

prowiki.org is down now, though, so you can't see it. Google has a cache:

http://www.google.com/search?q=cache:QgZctJ2jkQUJ:http://www.prowiki.org/wiki4d/wiki.cgi%3FLanguageSpecification/KeywordIndex

-- 
Remove ".doesnotlike.spam" from the mail address.
Aug 06 2007
parent Henrik <zodiachus gmail.com> writes:
Deewiant wrote:

 Dan wrote:

 A few things. Firstly, what's happened to the main comparison page: 
 http://www.digitalmars.com/d/comparison.html

 It's only showing stats for D.


 
 It got tonnes of complaints by non-D users about how their languages were being
 misrepresented. In the end, it was decided to take them out completely.
 


I think it was when DMD finally hit 1.0 (and thus got some extra 
attention). People would complain that "their" language indeed do have 
(insert feature here) and then show a two-page example on how to do this 
  via the language's standard library. Usually a D user would then point 
out somewhat smugly that the comparison page states that only language 
  features are compared - standard libraries are not included in the 
comparison. Although this may be true, the discussion would usually 
degenerate from there into some form of flame war with hurt feelings and 
bruised egos.
Programmers can be very dogmatic like that sometimes. Just as other 
people we tend to mix up what we do with who we are. I think it was 
decided that although the comparison page was technically correct, it 
had to be "truncated" a bit in the interests of public relations.
Aug 08 2007
prev sibling next sibling parent "Digital Mars" <Dave_member pathlink.com> writes:
"Dan" <twinbee41 skytopia.com> wrote in message 
news:f96gar$1vjv$1 digitalmars.com...

 Second thing. How does D allocate for a 2D (or even 3D) array. I tried to 
 look everywhere on the D site for this, and nothing came up. I'm just 
 curious to how it compares with the long-winded C/C++ way of using malloc 
 to create arrays.


Try this:

import std.stdio;
void main()
{
    int[][]   arr2d = new int[][](10,10);
    foreach(d; arr2d)
    {
        foreach(ref x; d)
        {
            x = 2;
        }
    }
    foreach(d; arr2d)
    {
        foreach(x; d)
        {
            writef(x);
        }
        writefln;
    }
    int[][][] arr3d = new int[][][](10,10,10);
    foreach(d2; arr3d)
    {
        foreach(d; d2)
        {
            foreach(ref x; d)
            {
                x = 3;
            }
        }
    }
    foreach(d2; arr3d)
    {
        foreach(d; d2)
        {
            foreach(x; d)
            {
                writef(x);
            }
            writef(" ");
        }
        writefln;
    }
}
Aug 07 2007
prev sibling parent "Dave" <Dave_member pathlink.com> writes:
"Dan" <twinbee41 skytopia.com> wrote in message
news:f96gar$1vjv$1 digitalmars.com...

 Second thing. How does D allocate for a 2D (or even 3D) array. I tried to
 look everywhere on the D site for this, and nothing came up. I'm just
 curious to how it compares with the long-winded C/C++ way of using malloc
 to create arrays.


Try this:

import std.stdio;
void main()
{
    int[][]   arr2d = new int[][](10,10);
    foreach(d; arr2d)
    {
        foreach(ref x; d)
        {
            x = 2;
        }
    }
    foreach(d; arr2d)
    {
        foreach(x; d)
        {
            writef(x);
        }
        writefln;
    }
    int[][][] arr3d = new int[][][](10,10,10);
    foreach(d2; arr3d)
    {
        foreach(d; d2)
        {
            foreach(ref x; d)
            {
                x = 3;
            }
        }
    }
    foreach(d2; arr3d)
    {
        foreach(d; d2)
        {
            foreach(x; d)
            {
                writef(x);
            }
            writef(" ");
        }
        writefln;
    }
}
Aug 07 2007