Re: Replace (ie: substitute) a type in varadic args

[Sean Campbell via Digitalmars-d-learn]

On Tuesday, 2 August 2016 at 07:24:28 UTC, Saurabh Das wrote:
How can I substitute the type of an argument received via a 
varadic template?

For example say I want to generalise this scenario:

auto myConverterFunction1(bool arg1, bool arg2, ubyte arg3, int 
arg4)
{
    return targetFunction(cast(ubyte)arg1, cast(ubyte)arg2, 
arg3, arg4);
}

So I'll have something like:

auto myConverterFunction2(Args...)(Args args)
{
    // Don't know how to do this part...
}

Basically I need to substitute bool for ubyte to interface with 
the Java JNI.

Thanks,
Saurabh

Just of the top of my head, using ugly string mixins, this:
auto myConverterFunc(Args...)(Args args)
{
        string genCode()
        {
            string code = "targetFunction(";
            foreach (i, Arg; Args)
            {
                static if (is(Arg == bool))
	            code ~= format("cast(ubyte)args[%s]%s", i, i == 
Args.length ? "" : ",");
                else
	            code ~= format("args[%s]%s", i, i == Args.length ? 
"" : ",");
            }
            code ~= ");";
            return code;
        }
    mixin(genCode());
}

void targetFunction(ubyte i, ubyte j, uint k, int l)
{
        writefln("i : %s, j : %s, k : %s, l : %s",i,j,k,l);
}

void main()
{
        myConverterFunc(true,false,10,20);
}