Data commit

Task/Binary-search/E/binary-search.e

@@ -0,0 +1,14 @@
+/** Returns null if the value is not found. */
+def binarySearch(collection, value) {
+    var low := 0
+    var high := collection.size() - 1
+    while (low <= high) {
+        def mid := (low + high) // 2
+        def comparison := value.op__cmp(collection[mid])
+        if      (comparison.belowZero()) { high := mid - 1 } \
+        else if (comparison.aboveZero()) { low := mid + 1 }  \
+        else if (comparison.isZero())    { return mid }      \
+        else                             { throw("You expect me to binary search with a partial order?") }
+    }
+    return null
+}