aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

Time for an 2014 update…

Browse source
This commit is contained in:
Ingy döt Net 2014-01-17 05:32:22 +00:00
parent 372c577f83
commit 09687c4926
2520 changed files with 34227 additions and 7318 deletions
Download patch file Download diff file Expand all files Collapse all files

40
Task/Y-combinator/D/y-combinator.d
View file

@ -1,31 +1,25 @@
import std.stdio, std.traits, std.algorithm, std.range;
auto Y(F)(F f) {
alias D = void delegate();
alias Ret = ReturnType!(ParameterTypeTuple!F);
alias Args = ParameterTypeTuple!(ParameterTypeTuple!F);
return ((Ret delegate(Args) delegate(D) x) =>
x(cast(D)x))(
(D y) =>
f((Args args) =>
(cast(Ret delegate(Args))(cast(D delegate(D))y)(y))(args)
)
);
auto Y(S, T...)(S delegate(T) delegate(S delegate(T)) f) {
static struct F {
S delegate(T) delegate(F) f;
alias f this;
}
return (x => x(x))(F(x => f((T v) => x(x)(v))));
}
void main() { // Demo code --------------------
auto factorial = Y((int delegate(int) self) =>
(int n) => 0 == n ? 1 : n * self(n - 1)
);
void main() { // Demo code:
auto factorial = Y((int delegate(int) self) =>
(int n) => 0 == n ? 1 : n * self(n - 1)
);
auto ackermann = Y((ulong delegate(ulong, ulong) self) =>
(ulong m, ulong n) {
if (m == 0) return n + 1;
if (n == 0) return self(m - 1, 1);
return self(m - 1, self(m, n - 1));
auto ackermann = Y((ulong delegate(ulong, ulong) self) =>
(ulong m, ulong n) {
if (m == 0) return n + 1;
if (n == 0) return self(m - 1, 1);
return self(m - 1, self(m, n - 1));
});
writeln("factorial: ", 10.iota.map!factorial);
writeln("ackermann(3, 5): ", ackermann(3, 5));
writeln("factorial: ", 10.iota.map!factorial);
writeln("ackermann(3, 5): ", ackermann(3, 5));
}