Ouch

basicspells.qnt

@@ -385,4 +385,42 @@ module basicSpells {
       assert(repeat(5,1) == [1,1,1,1,1]),
       assert(repeat(2,true) == [true,true])
   }
+
+
+  /// `listToSet(l)` is set of elements, generated from a list l.
+  ///
+  /// - @param n: list of elements
+  /// - @returns a set of elements.
+  pure def listToSet(l:List[a]): Set[a] = l.foldl(Set(), (acc,e) => acc.union(Set(e)))
+
+  run listToSetTest = all {
+      assert(listToSet([1,2,3]) == Set(1,2,3)),
+      assert(listToSet([1,1,1]) == Set(1)),
+  }
+
+  pure def dropFirst(l: List[a], cond: (a) => bool): List[a] = {
+    pure val result = l.foldl(([], true), (acc, e) => {
+      if (acc._2 and not(cond(e))) {
+        (acc._1.append(e), true)
+      } else if (not(acc._2)) {
+        (acc._1.append(e), acc._2)
+      } else {
+        (acc._1, false)
+      }
+    })
+
+    result._1
+  }
+
+  run dropFirstTest = all {
+    assert(dropFirst([1, 5, 4, 3], (x) => x % 2 != 1) == [1, 5, 3]),
+    assert(dropFirst([1,2,3,4,5], (x) => x == 12) == [1,2,3,4,5])
+  }
+
+  pure def mapToSet(m: a -> b):Set[(a,b)] = m.keys().fold(Set(),(acc, k) => acc.union(Set((k,m.get(k)))))
+
+  run mapToSetTest = {
+    assert(mapToSet(Map(1 -> 2, 3 -> 6)) == Set((1,2),(3,6)))
+  }
+
 }