Re: Templates and writing variable number of arguments

[ted via Digitalmars-d-learn]

try replacing:
final void output(T)(string text, T params...) const {
with
 final void output(T...)(string text, T params) const {


Andre Polykanine via Digitalmars-d-learn wrote:

> Hi everyone,
> It's me again.
> Now  I'm  struggling  with  the  `output` member function which should
> output  a  string  either  to  stdout  or  to a file, depending on the
> parameter.
> However,  I would like it to work like `writefln` with variable number
> of arguments:
> output("Hello %s!", "world"); // should be OK
> output("%s  %s:  %s  %d  times",  "I", "say", "Hello world!", 500); //
> Should also be OK
> 
> Here is my code:
> 
> final void output(T)(string text, T params...) const {
> if (this.outFile == "") {
> writefln(text, params);
> } else { // Output to a file
> auto f = File(this.outFile, "w");
> try {
> f.writefln(text, params);
> } catch(Exception e) {
> writefln("Unable to write to %s: %s",
> this.outFile, e.msg);
> }
> }
> }
> 
> And the compiler says it can't deduce the type of arguments.
> What am I doing wrong here?
> Maybe, I don't need such a function and all and there is a way to make
> it more elegant?
> Thanks!
> 

Templates and writing variable number of arguments

[Andre Polykanine via Digitalmars-d-learn]

Hi everyone,
It's me again.
Now  I'm  struggling  with  the  `output` member function which should
output  a  string  either  to  stdout  or  to a file, depending on the
parameter.
However,  I would like it to work like `writefln` with variable number
of arguments:
output("Hello %s!", "world"); // should be OK
output("%s  %s:  %s  %d  times",  "I", "say", "Hello world!", 500); //
Should also be OK

Here is my code:

final void output(T)(string text, T params...) const {
if (this.outFile == "") {
writefln(text, params);
} else { // Output to a file
auto f = File(this.outFile, "w");
try {
f.writefln(text, params);
} catch(Exception e) {
writefln("Unable to write to %s: %s", 
this.outFile, e.msg);
}
}
}

And the compiler says it can't deduce the type of arguments.
What am I doing wrong here?
Maybe, I don't need such a function and all and there is a way to make
it more elegant?
Thanks!

-- 
With best regards from Ukraine,
Andre
Skype: Francophile
Twitter: @m_elensule; Facebook: menelion
My blog: http://menelion.oire.org/