On Monday, 27 February 2017 at 02:02:57 UTC, ag0aep6g wrote:
Make a range or an array of function pointers from the AliasSeq
of function aliases:
----
import std.meta: staticMap;
import std.range: only;
enum fptr(alias f) = &f;
enum fptrs = staticMap!(fptr, funcs);
auto r = only(fptrs);
foreach (i, f; parallel(r))
values[i] = f(val);
----
Although this answers my question perfectly, it turns out that I
have simplified my case too much. It looks like existing
overloads are complicating the matter. (I am actually trying to
parallelise
https://github.com/PhilippeSigaud/Pegged/blob/master/pegged/peg.d#L1646.)
The problem seems to be
enum fptr(alias f) = &f;
(This is still a bit magical to me: it this a shorthand for a
template?)
Can the following be made to work?
int one(int) {return 1;}
int two(int) {return 2;}
int three(int) {return 3;}
int four(int) {return 4;}
int five(int) {return 5;}
int six(int) {return 6;}
int seven(int) {return 7;}
int eight(int) {return 8;}
int one(string) {return 0;} // How to ignore this?
int[8] values;
template eval_all(funcs...)
{
void eval_all(int val)
{
import std.meta: staticMap, Filter;
import std.range: only;
import std.parallelism;
import std.traits;
alias int function(int) iwant;
//enum fptr(alias f) = &f; // Error: cannot
infer type from
// overloaded
function symbol & one
enum fptr(alias int f(int)) = &f; // ditto.
enum fptrs = staticMap!(fptr, funcs);
auto r = only(fptrs);
foreach (i, f; parallel(r))
values[i] = f(val);
}
}
void main()
{
eval_all!(one, two, three, four, five, six, seven, eight)(42);
foreach(i, val; values)
assert(val == i + 1);
}
