Using closure causes GC allocation

[Vino.B via Digitalmars-d-learn]

On Saturday, 2 September 2017 at 20:54:03 UTC, Vino.B wrote:
> On Saturday, 2 September 2017 at 20:10:58 UTC, Moritz Maxeiner 
> wrote:
>> On Saturday, 2 September 2017 at 18:59:30 UTC, Vino.B wrote:
>>> [...]
>>
>> Cannot reproduce under Linux with dmd 2.076.0 (with commented 
>> out Windows-only check). I'll try to see what happens on 
>> Windows once I have a VM setup.
>>
>>> [...]
>>
>> You changed the type of dFiles, which you return from 
>> cleanFiles, without changing the return type of cleanFiles. 
>> Change the return type of cleanFiles to the type the compiler 
>> error above tells you it should be (`Tuple!(string, string)[]` 
>> instead of `string[][]`), or let the compiler infer it via 
>> auto (`auto cleanFiles(...`).
>
> Hi,
>
>  Thank you very much, was able to resolve the second code issue 
> by changing the return type of the function.

Hi,

   In order to resolve the issue "Using closure causes GC 
allocation" it was stated that we need to use delegates, can you 
please help me on how to as i have not gone that much far in D 
programming.

import std.stdio: File,writeln;
import std.datetime.systime: Clock, days, SysTime;
import std.file: SpanMode, dirEntries, exists, isFile, mkdir, 
remove;
import std.typecons: tuple, Tuple;
import std.algorithm:  filter, map, each;
import std.array: array;

Tuple!(string)[] logClean (string[] Lglst, int LogAge) {
	if (!Lglst[0].exists) { mkdir(Lglst[0]); }
	auto ct1 = Clock.currTime();
	auto st1 = ct1 + days(-LogAge);
	auto dFiles = dirEntries(Lglst[0], SpanMode.shallow).filter!(a 
=> a.exists && a.isFile && a.timeCreated < st1).map!(a => 
tuple(a.name)).array;
	dFiles.each!(a => a[0].remove);
	return dFiles;
}

void main () {
string[] LogDir = 
["C:\\Users\\bheev1\\Desktop\\Current\\Script\\D\\Logs"];
int  LogAge = 1;
logClean(LogDir,LogAge);
}

From,
Vino.B