Hello,

Here is a code with comments: https://run.dlang.io/is/BNl2Up.

I don't understand how to pass lambda into template.
I get an error:
>onlineapp.d(18): Error: template instance `qwerty!((i) => "arg" ~ i.to!string ~ "[0] == '?'", "||")` cannot use local __lambda1 as parameter to non-global template qwerty(alias mapper, alias delimiter)

On Monday, 3 September 2018 at 09:09:44 UTC, Andrey wrote:
> Hello,
>
> Here is a code with comments: https://run.dlang.io/is/BNl2Up.
>
> I don't understand how to pass lambda into template.
> I get an error:
>>onlineapp.d(18): Error: template instance `qwerty!((i) => "arg" ~ i.to!string ~ "[0] == '?'", "||")` cannot use local __lambda1 as parameter to non-global template qwerty(alias mapper, alias delimiter)

Not the best solution, but did you try to make querty template global adding a third parameter to pass count?

Andrea

On Monday, 3 September 2018 at 09:09:44 UTC, Andrey wrote:
> Hello,
>
> Here is a code with comments: https://run.dlang.io/is/BNl2Up.
>
> I don't understand how to pass lambda into template.
> I get an error:
>>onlineapp.d(18): Error: template instance `qwerty!((i) => "arg" ~ i.to!string ~ "[0] == '?'", "||")` cannot use local __lambda1 as parameter to non-global template qwerty(alias mapper, alias delimiter)

Congratulations, you've run into one of D's oldest and most annoying known bugs, issue 5710: https://issues.dlang.org/show_bug.cgi?id=5710

The solution is to define `qwerty` outside of `exec`, and add an additional parameter to pass in `count`: https://run.dlang.io/is/VTeizm

On Monday, 3 September 2018 at 09:09:44 UTC, Andrey wrote:
> Hello,
>
> Here is a code with comments: https://run.dlang.io/is/BNl2Up.
>
> I don't understand how to pass lambda into template.
> I get an error:
>>onlineapp.d(18): Error: template instance `qwerty!((i) => "arg" ~ i.to!string ~ "[0] == '?'", "||")` cannot use local __lambda1 as parameter to non-global template qwerty(alias mapper, alias delimiter)

Try this:

if(mixin(qwerty!((int i) => "arg" ~ i.to!string ~ "[0] == '?'", "||")))