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authorJacek Sieka <arnetheduck@gmail.com>2016-08-25 22:59:51 +0800
committerJacek Sieka <arnetheduck@gmail.com>2016-08-25 22:59:51 +0800
commitdb2f96daba9c04db2f24cb783c79fb37799cd9ea (patch)
tree567beb43c7e4549abfcae1ea66e5232d7525e001 /tests/closure/tflatmap.nim
parent3116744c86f37ac4e4e5fec3d6d1635304ed717f (diff)
parent84a09d2f5b0866491e55fef0fef541e8cc548852 (diff)
downloadNim-db2f96daba9c04db2f24cb783c79fb37799cd9ea.tar.gz
Merge remote-tracking branch 'origin/devel' into initallocator-fix
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diff --git a/tests/closure/tflatmap.nim b/tests/closure/tflatmap.nim
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+
+# bug #3995
+
+import future
+
+type
+  RNG* = tuple[]
+  Rand*[A] = (RNG) -> (A, RNG)
+
+proc nextInt*(r: RNG): (int, RNG) =
+  (1, ())
+
+proc flatMap[A,B](f: Rand[A], g: A -> Rand[B]): Rand[B] =
+  (rng: RNG) => (
+    let (a, rng2) = f(rng);
+    let g1 = g(a);
+    g1(rng2)
+  )
+
+proc map[A,B](s: Rand[A], f: A -> B): Rand[B] =
+  let g: A -> Rand[B] = (a: A) => ((rng: RNG) => (f(a), rng))
+  flatMap(s, g)
+
+let f = nextInt.map(i => i - i mod 2)