Re: Is there any hope for "lazy" and @nogc?

[Steven Schveighoffer via Digitalmars-d]

On 8/1/18 10:14 PM, Shachar Shemesh wrote:
On 01/08/18 17:13, Steven Schveighoffer wrote:
The lazy variadic thing is a distinction between specifying variadic 
lazy parameters and a lazy variadic array.

I have now read that sentence 4 times, and I still have no idea what it 
means.

Can you give examples of both?

import std.stdio;

// lazy variadic array
void foo(lazy int[] arr...)
{
  writeln(arr[0]);
  writeln(arr[1]);
  writeln(arr[2]);
}

// variadic lazy paramters
void bar(int delegate()[] items...)
{
   writeln(items[0]());
   writeln(items[1]());
   writeln(items[2]());
}

int param(int x)
{
    writeln("param ", x);
    return x;
}

void main()
{
    foo(param(0), param(1), param(2));
    bar(param(0), param(1), param(2));
}

output:

param 0
param 1
param 2
0
param 0
param 1
param 2
1
param 0
param 1
param 2
2
param 0
0
param 1
1
param 2
2

So in the first case, the ENTIRE array is evaluated lazily, and then an 
element selected. In the second case, each item is evaluated when used.

-Steve