On Tuesday, 18 August 2015 at 15:51:55 UTC, ixid wrote:
Though sugar seems to be somewhat looked down upon I thought I'd suggest this- having seen the cartesianProduct function from std.algorithm in another thread I thought it would be an excellent piece of sugar in the language. It's not an earth shattering change but it makes something very common more elegant and reduces indentation significantly for multiple nested loops. Braces make nested loops very messy and any significant quantity of code in the loop body benefits from not being in a messy nesting.

import std.algorithm, std.range, std.stdio;


void main() {
        // Standard
        foreach(i; 0..10)
                foreach(j; 0..10)
                        foreach(k; 0..10)
                                writeln(i, j, k);
        
        // Better
        foreach(k, j, i; cartesianProduct(10.iota, 10.iota, 10.iota))
                writeln(i, j, k);
        
        
        // Sugar
        foreach(k, j, i; 0..10, 0..10, 0..10)
                writeln(i, j, k);

        //Following brace rules
        // Standard
        foreach(i; 0..10)
        {
                foreach(j; 0..10)
                {
                        foreach(k; 0..10)
                        {
                                writeln(i, j, k);
                        }
                }
        }
                
        // Sugar
        foreach(k, j, i; 0..10, 0..10, 0..10)
        {
                writeln(i, j, k);
        }


You can create a multi-loop quite easily in template form for avoid the nesting.

Essentially use an array for the the index instead of individual variables, e.g.,


mutliloop([0..10, 0..10, 0..10], (i)=>
{
   writeln(i[0], i[1], i[2]);
});


I'm not sure how efficient it is but essentially achieves what you are asking without too much overhead. Obviously having good language support is always nice...

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