# Formatting

Decodal includes an initial source formatter for parsed Decodal code.
The formatter is available from the Rust crate, the CLI, the WebAssembly package, and the playground.

## CLI

Print formatted source to stdout:

```sh
decodal fmt config.dcdl
```

Format in place:

```sh
decodal fmt --write config.dcdl
```

Read from stdin:

```sh
cat config.dcdl | decodal fmt -
```

## Rust

```rust
let formatted = decodal::format_source("Server={port=Int default 8080;};")?;
```

## WebAssembly

```js
import init, { formatSource } from 'decodal-wasm';

await init();
const result = JSON.parse(formatSource('Server={port=Int default 8080;};'));

if (result.ok) {
  console.log(result.source);
} else {
  console.error(result.error);
}
```

## Current limitation

The formatter currently rejects source containing line comments rather than silently dropping them.
Comment-preserving formatting requires attaching comments to syntax nodes or formatting from a concrete syntax tree, and should be implemented before comment-heavy source is formatted automatically.