Re: Taking a function or delegate as argument.

[bls]

On 01/10/2012 06:53 AM, Jacob Carlborg wrote:

On 2012-01-10 14:48, simendsjo wrote:

On 10.01.2012 14:43, Mike Parker wrote:

On 1/10/2012 10:05 PM, simendsjo wrote:

If I want to have a method taking a callback function, I have to
specify
if it should take a function or delegate even if I don't really care.
What's the best way to accept either? I cannot see any wrapper for
something like this in std.typecons.

The simple way:

void callback(int i, void delegate(int) dg)
{
dg(i);
}

void callback(int i, void function(int) fn)
{
void wrap(int j)
{
function(j);
}
callback(i, &wrap);
}

Yeah, but a bit tedious.. I found toDelegate:
http://dlang.org/phobos/std_functional.html#toDelegate

Or make it a template parameter and check if it's callable using
std.traits.isCallable.

What's wrong with toDelegate ? Seems to be pretty handy.

//simple snip
import std.functional;

int main()
{
    int delegate( int i) dg;
    alias dg callback;
    callback = toDelegate(&test);
    writeln( callback( 12 ) );
    readln();

    return 0;
}

int test(int i) { return 30 +i;}