On Thursday, 12 May 2016 at 10:38:37 UTC, Dsby wrote:
I write one, bind functon to a delegate.
In here:
https://github.com/putao-dev/collie/blob/master/source/collie/utils/functional.d
this is the code:
auto bind(T,Args...)(auto ref T fun,Args args) if
(isCallable!(T))
{
alias FUNTYPE = Parameters!(fun);
static if(is(Args == void))
{
static if(isDelegate!T)
return fun;
else
return toDelegate(fun);
}
else static if(FUNTYPE.length > args.length)
{
alias DTYPE = FUNTYPE[args.length..$];
return
delegate(DTYPE ars){
TypeTuple!(FUNTYPE) value;
value[0..args.length] = args[];
value[args.length..$] = ars[];
return fun(value);
};
}
else
{
return delegate(){return fun(args);};
}
}
Thank you. Would you agree to help me understand it ?
The only thing I don't understand is why the function template
argument is defined as T and the argument as auto ref T fun. Why
the auto ref and not alias T in the template argument list ?
This bind is better than Partial!() from std.functional since it
accepts any number of parameters. But the given parameters are
passed as first arguments of fun. The std::bind of C++ allows to
bind any parameter in any order and eventually multiple times.
It's really as if a new function was defined with a total liberty
degree on its signature.
Anyway thank you very much.
