60 lines
1.3 KiB
Rust
60 lines
1.3 KiB
Rust
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use std;
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import std::vec;
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import std::rand;
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import std::option;
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// random uint less than n
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fn under(r : rand::rng, n : uint) -> uint { assert n != 0u; r.next() as uint % n }
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// random choice from a vec
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fn choice<T>(r : rand::rng, v : [T]) -> T { assert vec::len(v) != 0u; v[under(r, vec::len(v))] }
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// 1 in n chance of being true
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fn unlikely(r : rand::rng, n : uint) -> bool { under(r, n) == 0u }
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tag maybe_pointy {
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no_pointy;
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yes_pointy(@pointy);
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}
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type pointy = {
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mutable x : maybe_pointy,
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mutable y : maybe_pointy,
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mutable z : fn()->()
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};
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iter allunder(n: uint) -> uint {
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let i: uint = 0u;
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while i < n { put i; i += 1u; }
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}
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fn nopT(_x : @pointy) { }
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fn nop() { }
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fn test_cycles(r : rand::rng)
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{
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const max : uint = 10u;
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let v : [mutable @pointy] = [mutable];
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for each i in allunder(max) {
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v += [mutable @{ mutable x : no_pointy, mutable y : no_pointy, mutable z: nop }];
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}
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for each i in allunder(max) {
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v[i].x = yes_pointy(v[under(r, max)]);
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v[i].y = yes_pointy(v[under(r, max)]);
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v[i].z = bind nopT(v[under(r, max)]);
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}
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// Drop refs one at a time
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for each i in allunder(max) {
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v[i] = @{ mutable x : no_pointy, mutable y : no_pointy, mutable z: nop };
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}
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}
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fn main()
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{
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let r = rand::mk_rng();
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test_cycles(r);
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}
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