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digitalmars.D.announce - columnar struct storage template

reply BCS <ao pathlink.com> writes:
If you have an array of structs that is primarily accessed by columns (the 
same member in each item) rather than by rows (all members in a given item) 
it can be faster to store the members each in there own array. The Columns 
template automates this for POD struct types.

http://www.dsource.org/projects/scrapple/browser/trunk/columns/columns.d
Dec 13 2008
parent reply Nestor <nestorperez2016 yopmail.com> writes:
On Saturday, 13 December 2008 at 21:13:52 UTC, BCS wrote:

 If you have an array of structs that is primarily accessed by 
 columns (the same member in each item) rather than by rows (all 
 members in a given item) it can be faster to store the members 
 each in there own array. The Columns template automates this 
 for POD struct types.

 http://www.dsource.org/projects/scrapple/browser/trunk/columns/columns.d


This no longer compiles on recent versions of DMD :(
Jan 29 2017
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Sunday, 29 January 2017 at 13:09:18 UTC, Nestor wrote:

 This no longer compiles on recent versions of DMD :(


Trivial fix though, it just needs to say "\n" instead of plain \n 
(it is missing quotes, D used to allow that for whatever stupid 
reason and has since been fixed).

Actually, tbh, I'm surprised it isn't a bigger fix needed given 
that that post is from 9 years ago!
Jan 29 2017
parent reply Nestor <nestorperez2016 yopmail.com> writes:
On Sunday, 29 January 2017 at 13:45:12 UTC, Adam D. Ruppe wrote:

 On Sunday, 29 January 2017 at 13:09:18 UTC, Nestor wrote:

 This no longer compiles on recent versions of DMD :(


 Trivial fix though, it just needs to say "\n" instead of plain 
 \n (it is missing quotes, D used to allow that for whatever 
 stupid reason and has since been fixed).

 Actually, tbh, I'm surprised it isn't a bigger fix needed given 
 that that post is from 9 years ago!


Where is it missing the quotes? I tried fixing it like this, but 
it still doesn't compile:

"(){return members["~j.stringof~"];}\"\n\""
Jan 29 2017
parent reply ezneh <petitv.isat gmail.com> writes:
On Sunday, 29 January 2017 at 14:00:37 UTC, Nestor wrote:

 On Sunday, 29 January 2017 at 13:45:12 UTC, Adam D. Ruppe wrote:

 On Sunday, 29 January 2017 at 13:09:18 UTC, Nestor wrote:

 This no longer compiles on recent versions of DMD :(


 Trivial fix though, it just needs to say "\n" instead of plain 
 \n (it is missing quotes, D used to allow that for whatever 
 stupid reason and has since been fixed).

 Actually, tbh, I'm surprised it isn't a bigger fix needed 
 given that that post is from 9 years ago!


 Where is it missing the quotes? I tried fixing it like this, 
 but it still doesn't compile:

 "(){return members["~j.stringof~"];}\"\n\""


Here :

  foreach(uint  u; FooCol.j) writef("%s ", u); writef(\n);
Jan 29 2017
parent Nestor <nestorperez2016 yopmail.com> writes:
On Sunday, 29 January 2017 at 14:16:37 UTC, ezneh wrote:

 Here :

  foreach(uint  u; FooCol.j) writef("%s ", u); writef(\n);


I see, but apparently this isn't the only issue. I replaced the 
whole unittest with this, and it still doesn't compile:

import std.stdio;
void main() {
   struct MyStruct {
     uint   i;
     float  j;
   }
   MyStruct data;
   Columns!(MyStruct) MyCols;
}

Problems this time were in the AfterLast function, which I 
modified like this:

string AfterLast(string s, char c) {
   foreach_reverse(int i, char d; s) if(c==d) return s[i+1..$];
   return s;
}

However there are still some errors which I don´t know how to fix:

columns1.d(45): Error: cannot implicitly convert expression 
(this) of type Columns!(MyStruct) to Columns!(MyStruct)*
columns1.d(63): Error: template instance 
columns1.Columns!(MyStruct) error instantiating


Line 63 is the declaration of MyCols, and line 45 would be thisÑ

At opIndex(uint i) { return At(this,i); }
Jan 29 2017