alias type = real;
alias func = type function(type a);

void main()
{
  import std.range;
  auto range = 10.iota!type(14, .5);

  alias fun1 = (type a) => a * a;
  alias fun2 = (type a) => a * 2;
  alias fun3 = (type a) => a + 1;
  alias fun4 = (type a) => a - 1;
  alias fun5 = (type a) => a / 2;

  import std.typecons;
  auto funs = tuple(fun1, fun2, fun3, fun4, fun5);

  import std.stdio;
  foreach(fun; funs)
  {
	fun(10).write(" "); // Perfect...
  }
  writeln; // 100 20 11 9 5

  import std.algorithm;
  auto sum = (type a, type b) => a + b;
  foreach(fun; funs)
  {
	range.map!fun
	     .reduce!sum
	     .write(" "); // Opps!
  }
  writeln; // 1115 1115 1115 1115 1115

  range.map!fun1.reduce!sum.write(" "); // "1115" Ok!
  range.map!fun2.reduce!sum.write(" "); // "188"  Ok!
  range.map!fun3.reduce!sum.write(" "); // "102"  Ok!
  range.map!fun4.reduce!sum.write(" "); // "86"   Ok!
  range.map!fun5.reduce!sum.write(" "); // "47"   Ok!
} /*
   * EXPECTED RESULTS:
   *
   *  1115 188 102 86 47
   *
   */

Hi all,

I get an unexpected result inside the second foreach() loop. Anyone know your reason?

SDB@79

On Wednesday, 20 April 2022 at 08:04:42 UTC, Salih Dincer wrote:

It's my fault, here is the solution:

  foreach(fun; funs)
  {
	range.map!(a => fun(a))
	     .reduce!sum
	     .write(" "); // Ok!
  }
  writeln; // "1115 188 102 86 47"

On Wednesday, 20 April 2022 at 08:37:09 UTC, Salih Dincer wrote:

  foreach(fun; funs)
  {
	range.map!(a => fun(a))
	     .reduce!sum
	     .write(" "); // Ok!
  }
  writeln; // "1115 188 102 86 47"

With the original version, I'm getting expected results with 2.098.1. run.dlang.io with 'dmd' also shows expected results.

On Wednesday, 20 April 2022 at 08:04:42 UTC, Salih Dincer wrote:

alias type = real;
alias func = type function(type a);

[...]

I think technically you should have save after range in that loop.