• =?UTF-8?Q?Christian_K=c3=b6stlin?= (51/51) May 19 2019 I would like to join several sorted files into one big sorted file.
• Jacob Carlborg (5/7) May 19 2019 In general you can use `typeof()`, where `` is
• =?UTF-8?Q?Christian_K=c3=b6stlin?= (54/62) May 19 2019 Thanks for the hint. The best I could come up with this is:
• =?UTF-8?Q?Christian_K=c3=b6stlin?= (51/51) May 19 2019 Last version using more from the outer template

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

I would like to join several sorted files into one big sorted file.

For that I came up with this snippet:


import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;

auto byMinimum(Ranges)(Ranges ranges)
{
     auto getNonEmpty()
     {
         return ranges.filter!("!a.empty");
     }

     auto nonEmpty = getNonEmpty;
     struct ByMinimum(Ranges)
     {
         bool empty()
         {
             return nonEmpty.empty;
         }

         auto front()
         {
             auto minRangeAndLine = nonEmpty.map!(range => tuple!("range",
                     "line")(range, range.front)).minElement!("a.line");
             return minRangeAndLine;
         }

         void popFront()
         {
             auto minRangeAndLine = nonEmpty.map!(range => tuple!("range",
                     "line")(range, range.front)).minElement!("a.line");
             minRangeAndLine.range.popFront;
             nonEmpty = getNonEmpty;
         }
     }

     return ByMinimum!(Ranges)();
}

void main(string[] files)
{
     foreach (n; files[1 .. $].map!(name => 
File(name).byLine(No.keepTerminator)).array.byMinimum)
     {
         writeln(n.line);
     }
}


I would like to get rid of the duplication that searches for the range 
with the next minimum in terms of runtime but also in terms of code 
written out. Unfortunately I have no idea how to even store the result 
of this search in an attribute of ByMinimum, as I cannot writeout its type.

Kind regards,
Christian

Jacob Carlborg <doob me.com> writes:

On 2019-05-19 15:36, Christian Köstlin wrote:

 Unfortunately I have no idea how to even store the result 
 of this search in an attribute of ByMinimum, as I cannot writeout its type.

In general you can use `typeof(<expression>)`, where `<expression>` is 
the expression you want to get the type of.

-- 
/Jacob Carlborg

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

On 19.05.19 20:38, Jacob Carlborg wrote:
 On 2019-05-19 15:36, Christian Köstlin wrote:
 
 Unfortunately I have no idea how to even store the result of this 
 search in an attribute of ByMinimum, as I cannot writeout its type.

 
 In general you can use `typeof(<expression>)`, where `<expression>` is 
 the expression you want to get the type of.
 

Thanks for the hint. The best I could come up with this is:


import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;
import std.traits;

auto byMinimum(Ranges)(Ranges ranges)
{
     auto getNonEmpty()
     {
         return ranges.filter!("!a.empty");
     }

     auto minimumOfRanges(Ranges)(Ranges ranges) {
         // dfmt off
         return ranges
             .map!(range => tuple!("range", "line")(range, range.front))
             .minElement!("a.line");
         // dfmt on
     }
     auto nonEmpty = getNonEmpty;
     ReturnType!(minimumOfRanges!(typeof(nonEmpty))) minRangeAndLine;
     struct ByMinimum(Ranges)
     {
         bool empty()
         {
             return nonEmpty.empty;
         }

         auto front()
         {
             minRangeAndLine = minimumOfRanges(nonEmpty);
             return minRangeAndLine;
         }

         void popFront()
         {
             minRangeAndLine.range.popFront;
             nonEmpty = getNonEmpty;
         }
     }
     return ByMinimum!(Ranges)();
}

void main(string[] files)
{
     foreach (n; files[1 .. $].map!(name => 
File(name).byLine(No.keepTerminator)).array.byMinimum)
     {
         writeln(n.line);
     }
}


Still it looks a little clumsy. Any ideas?

--
Christian

=?UTF-8?Q?Christian_K=c3=b6stlin?= <christian.koestlin gmail.com> writes:

Last version using more from the outer template


import std.stdio;
import std.algorithm;
import std.typecons;
import std.array;
import std.range;
import std.traits;

auto byMinimum(Ranges)(Ranges ranges)
{
     auto getNonEmpty()
     {
         return ranges.filter!("!a.empty");
     }

     auto nonEmpty = getNonEmpty;

     auto minimumOfRanges()
     {
         // dfmt off
         return nonEmpty
             .map!(range => tuple!("range", "line")(range, range.front))
             .minElement!("a.line");
         // dfmt on
     }

     ReturnType!(minimumOfRanges) minRangeAndLine;
     struct ByMinimum
     {
         bool empty()
         {
             return nonEmpty.empty;
         }

         auto front()
         {
             minRangeAndLine = minimumOfRanges;
             return minRangeAndLine;
         }

         void popFront()
         {
             nonEmpty = getNonEmpty;
             minRangeAndLine.range.popFront;
         }
     }

     return ByMinimum();
}

void main(string[] files)
{
     foreach (n; files[1 .. $].map!(name => 
File(name).byLine(No.keepTerminator)).array.byMinimum)
     {
         writeln(n.line);
     }
}