On Tuesday, 21 December 2021 at 08:26:17 UTC, rempas wrote:
On Tuesday, 21 December 2021 at 08:11:39 UTC, Anonymouse wrote:
I'm not certain I understand, but won't `foreach (i, a; args)
{ /* ... */ }` in his example do that?
As in, if you necessarily must index `args` instead of using a
foreach variable,
```d
import core.stdc.stdio : putc, stdout;
void print(T...)(string prompt, T args)
{
foreach (i, a; args)
{
alias A = typeof(args[i]);
static if (is(A : string))
{
for (int j = 0; j < args[i].length; j++)
{
putc(args[i][j], stdout);
}
}
else
{
// handle your other types
print("", A.stringof);
}
}
}
void main()
{
print("Prompt (ignored)", "Hello", " world!\n", 123);
}
```
No it will not. I will try to explain it the best way I can.
When I say I want to index args, I mean that I want to index
and choose which argument to use rather than use them
continuously one after another inside a `foreach`. For example
check the following call:
`print("Hello %s!%c", "world", '\n');`
In that case I want to first print print from "H" up to (but
not include) "%s". Then I want to print the first argument.
After that, I want to print the '!' character and then I want
to print the second argument. So I need a way to keep track
which argument was the last one I printed and manually choose
which argument to use. So `foreach` will not do in that case
because I don't want to continuously use the arguments one
after another. Is is more clear now? "writef" exists in phobos
so I'm pretty sure that there is a way to do that.
You can use switch + static foreach:
```d
import std.stdio;
//this print args in reverse order:
void print(T...)(string prompt, T args)
{
void print_arg(size_t index){
switch(index){
static foreach(i, a; args){
case i:
// handle your other types
write(a);
return;
}
default:
assert(0, "no impl");
}
}
write(prompt);
size_t len = args.length;
while(len --> 0)
print_arg(len);
}
void main(){
print("Prompt (ignored): ", "Hello", " world!\n", 123);
}
```
