# Feature: AST to AST conversion
Note: that specs support rich text formatting.
In particular, rewrites preserve _emphasized text_, **bold text** and ~strikethrough text~!
## Background
Given `pipeline` as:
```rust
let output = display(ast_to_ast(parse(input)));
```
And `environment` as:
```sql
CREATE TABLE s(x int, y int);
CREATE TABLE t(x int, y int);
```
## Example: Constant queries (1)
When `input` is:
```sql
SELECT 1;
```
Then `output` is:
```sql
SELECT 1;
```
## Example: Linear queries (2)
When `input` is:
```sql
SELECT '_foo_' as x, '*bar*' as y;
```
Then `output` is:
```sql
SELECT
'_foo_' as x,
'*bar*' as y;
```