---
title: "reference-book/9-common-patterns/loops"
source: reference-book
version: genesis-0-1-0
id: reference-book/9-common-patterns/loops
canonical: /docs/reference-book/9-common-patterns/loops
---


As you know Simorg doesn't have any third party entity sitting in the code dictating its own rules to the data. Instead, we believe in data-driven approaches by which the data is being streamed in certain paths which demonstrate certain behaviors.

Loops are a great example of this data-driven approach.

This code is demonstrating a typical classical loop in the C language,
```
for (int i = 10; i>0; i--) {
  printf("index: %d", i);
}
```

Now the same code according to a data-driven pattern is like,
```
$i >0 -- i ?
10 i
```
The above code is having a post-declaration syntax of a variable that continues reducing the counter and pushing data back into pipeline's head until it reaches 0.

We can even use a gate and make it a self-starting counter.

```
:[10, :] $i > 0 -- i ?
```

The point here is that we made the behavior of a loop using a data-driven approach.

If the initializer is always a positive value then the above loop can be even more simplified as,
```
$i--&i ?
10 i
```
Here, the truthy check operator <<<&>>> is replacing $$$KeywordSnippet keyword=>0 $$$ . This is possible because <<<&>>> will pass the vibration only if the incoming is a truthy value hence, preventing the flow to continue when <<<i>>> is <<<0>>>.


A typical usage of loop in **CPL**s is when we want to iterate over collections of items. Simorg doesn't need that approach either. As the collection itself naturally is iterable using <<<Collector Operator>>> so still the behavior of <<<foreach>>> is following a data-driven pattern.