Passing Template to Function

[Vino]

Hi All,

  Request you help on the below program as it error out with the 
below error

Error:
UDictCompression.d(31): Error: template UDictCompression.compress 
cannot deduce function from argument types !()(string), 
candidates are:
UDictCompression.d(19):        
UDictCompression.compress(T)(Array!T col)

Program:
import std.algorithm: countUntil, joiner, sort, uniq, map;
import std.csv: csvReader;
import std.stdio: File, writeln;
import std.typecons: Tuple, tuple;
import std.meta: AliasSeq;
import std.container.array;

alias ColumnTypes = AliasSeq!(string, string, int);
alias Arr(T) = Array!T;

auto readData() {
auto file = 
File("C:\\Users\\bheev1\\Desktop\\Current\\Script\\Others\\TColRead.csv", "r");
Arr!(Tuple!ColumnTypes) res;
foreach (record; 
file.byLineCopy.joiner("\n").csvReader!(Tuple!ColumnTypes))
	{ res.insertBack(record); }	
	return res;
}

auto compress(T)(Array!T col) {
     Arr!int ks; Array!T vals;
     vals.insertBack(sort(col.dup[]).uniq);
	ks.insertBack(col.map!(v => vals.countUntil(v)));
	return tuple(vals, ks);
}

void main() {
	auto columns = readData[];
	foreach(r; columns)
	{
		foreach(i, ColT; ColumnTypes) {
			auto vk = compress(r[i]);
			writeln(vk[0][], vk[1][]);
			}
	}
}

From,
Vino.B