# Optimization

The `-O level` command-line option controls the level of optimization before the execution begins.

Currently, there are three level of optimization available:

```
0 -- Does nothing. (default)
1 -- Does constant folding on the AST. (recommended)
2 -- Does constant folding, after which it deparses the AST into Sidef code, parses the code again and does more constant folding on the new AST.
```

In the end, the code is translated to Perl and is ready to be executed. In the translation process, however, more non-optional optimizations are performed, such as loop and scope optimizations.