How to instantiate a map with multiple functions

[Ali Çehreli via Digitalmars-d-learn]

On 12/26/2015 11:46 AM, karthikeyan wrote:

 > Thanks but the following returns an error for me
 >
 >    import std.algorithm.comparison : equal;
 >    import std.range : chain;
 >    int[] arr1 = [ 1, 2, 3, 4 ];
 >    int[] arr2 = [ 5, 6 ];
 >    auto dd = map!(z => z * z, c => c * c * c)(chain(arr1, arr2));
 >    writeln(dd);
 >
 > Error :
 >
 > /usr/include/dmd/phobos/std/meta.d(546): Error: template instance
 > F!(__lambda2) cannot use local '__lambda2' as parameter to non-global
 > template AppliedReturnType(alias f)

That looks like a bug to me. Please report here:

   https://issues.dlang.org/

You can call tuple() as a workaround:

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

void main() {
     int[] arr1 = [ 1, 2, 3, 4 ];
     int[] arr2 = [ 5, 6 ];
     auto dd = map!(z => tuple(z * z, z * z * z))(chain(arr1, arr2));
     writeln(dd);
}

Ali