On 24.01.15 15:53, Andrei Alexandrescu wrote:
On 1/24/15 4:13 AM, zeljkog wrote:
On 24.01.15 12:50, Peter Alexander wrote:
auto f = unique();
[1, 5, 5, 2, 1, 5, 6, 6].filter!(f).writeln; // [1, 5, 2, 6]
Filter needs an alias, and you cannot alias an R-value (it has no
symbol).
Yes, I see :)
But I think this should be supported by std.algorithm:
import std.stdio, std.algorithm;
struct Uniq{
bool[int] c;
bool opCall(int a){
if (a in c)
return false;
else{
c[a] = true;
return true;
}
}
}
void main()
{
[1, 5, 5, 2, 1, 5, 6, 6].filter!Uniq.writeln;
}
I can't make sense of this - where is Uniq supposed to be instantiated?
-- Andrei
Require following changes in std.algorithm.filter.
original:
template filter(alias predicate) if (is(typeof(unaryFun!predicate)))
{
auto filter(Range)(Range range) if (isInputRange!(Unqual!Range))
{
return FilterResult!(unaryFun!predicate, Range)(range);
}
}
private struct FilterResult(alias pred, Range)
...
changed (to run this case):
template filter(alias predicate) if (is(typeof(unaryFun!predicate)))
{
auto filter(Range)(Range range) if (isInputRange!(Unqual!Range))
{
static if (is(predicate == struct))
return FilterResult!(predicate, Range)(range);
else
return FilterResult!(unaryFun!predicate, Range)(range);
}
}
private struct FilterResult(alias predicate, Range)
{
static if (is(predicate == struct))
predicate pred;
else
alias pred = predicate;
...
