• Andrey (7/16) Aug 27 2018 I don't want to write manually these four "or" conditions because
• Kamil Koczurek (4/21) Aug 27 2018 Mixins seem to be an overkill here. Maybe something like this
• Andrey (27/30) Aug 27 2018 Here there is dynamic code, with memory allocs.

Andrey <saasecondbox yandex.ru> writes:

Hello again,
I have this part of code:
 ...
if(index + 3 >= data.length || data[index + 1][0] == '&' || 
data[index + 2][0] == '&' || data[index + 3][0] == '&' || 
data[index + 4][0] == '&')
{
    writeln("Some text...");
}

I don't want to write manually these four "or" conditions because 
in each case I know at compile time how many conditions should be.
I would be great if I could do something like this:
if(index + 3 >= data.length || mixin OrCondition!4) { ... }

where "OrCondition" will insert text using this expression:
 data[index + j][0] == '&' // j is between [1 and 4]

I know that it is possible but don't know how to implement...

Kamil Koczurek <koczurekk gmail.com> writes:

On Monday, 27 August 2018 at 11:52:02 UTC, Andrey wrote:
 Hello again,
 I have this part of code:
 ...
if(index + 3 >= data.length || data[index + 1][0] == '&' || 
data[index + 2][0] == '&' || data[index + 3][0] == '&' || 
data[index + 4][0] == '&')
{
    writeln("Some text...");
}

 I don't want to write manually these four "or" conditions 
 because in each case I know at compile time how many conditions 
 should be.
 I would be great if I could do something like this:
if(index + 3 >= data.length || mixin OrCondition!4) { ... }

 where "OrCondition" will insert text using this expression:
 data[index + j][0] == '&' // j is between [1 and 4]

 I know that it is possible but don't know how to implement...

Mixins seem to be an overkill here. Maybe something like this 
would suffice:

data[index + 1 .. index + 5].map!(k => k[0]).array == "&&&&"

Andrey <saasecondbox yandex.ru> writes:

On Monday, 27 August 2018 at 11:56:08 UTC, Kamil Koczurek wrote:
 Mixins seem to be an overkill here. Maybe something like this 
 would suffice:

 data[index + 1 .. index + 5].map!(k => k[0]).array == "&&&&"

Here there is dynamic code, with memory allocs.

I found solution:
-----------------------
import std.meta;
import std.traits;
import std.stdio;
import std.array : join;
import std.algorithm.iteration : map;
import std.conv : to;
import std.range;

string qaz(alias args, alias index, ubyte count)()
{
     return iota(1, count).map!(j => args.stringof ~ '[' ~ 
index.stringof ~ '+' ~ j.to!string ~ "][0] == '&'").join("||");
}

void main()
{
     ushort index = 1;
     string[] args = ["&second", "123", "&qaz", "true", "&first", 
"77", "&value"];

     if(index + 1 >= args.length || mixin(qaz!(args, index, 4)))
     {
         writeln(qaz!(args, index, 4)());
     }
}
-----------------------