Initial project import

tools/v/vlib/arrays/index_of.v

@@ -0,0 +1,26 @@
+module arrays
+
+// index_of_first returns the index of the first element of `array`, for which the predicate fn returns true.
+// If predicate does not return true for any of the elements, then index_of_first will return -1.
+// Example: assert arrays.index_of_first([4,5,0,7,0,9], fn(idx int, x int) bool { return x == 0 }) == 2
+pub fn index_of_first[T](array []T, predicate fn (idx int, elem T) bool) int {
+	for i, e in array {
+		if predicate(i, e) {
+			return i
+		}
+	}
+	return -1
+}
+
+// index_of_last returns the index of the last element of `array`, for which the predicate fn returns true.
+// If predicate does not return true for any of the elements, then index_of_last will return -1.
+// Example: assert arrays.index_of_last([4,5,0,7,0,9], fn(idx int, x int) bool { return x == 0 }) == 4
+pub fn index_of_last[T](array []T, predicate fn (idx int, elem T) bool) int {
+	for i := array.len - 1; i >= 0; i-- {
+		e := array[i]
+		if predicate(i, e) {
+			return i
+		}
+	}
+	return -1
+}