# Generate Parsers with Codama

This guide walks you through generating a [Vixen](https://github.com/rpcpool/yellowstone-vixen) Parser using [Codama](https://github.com/abklabs/codama), a tool for rendering Rust SDKs and parser implementations from IDLs.

Vixen is a framework for building real-time program data pipelines in Rust. This guide helps you scaffold a parser that can be used in the Vixen runtime to decode and process Solana program data.

#### Prerequisites

1. **An `idl.json` file:** Either Anchor-generated or custom.
2. **Install** [**pnpm**](https://pnpm.io/)**:** Or use npm/yarn if preferred.
3. **Initialize a JavaScript Project:**

   ```bash
   pnpm init
   ```

#### Installation

Install the required Codama packages:

```bash
pnpm install @codama/renderers-vixen-parser
```

Also, install dependencies for the parser generation script:

```bash
pnpm install \
  @codama/nodes \
  @codama/nodes-from-anchor \
  @codama/renderers-core \
  @codama/visitors-core
```

#### Setup

**Create a Parser Generation Script**

Create a new file, `codama.cjs`:

```javascript
const path = require("node:path");
const { rootNode } = require("@codama/nodes");
const { rootNodeFromAnchor } = require("@codama/nodes-from-anchor");
const { readJson } = require("@codama/renderers-core");
const { visit } = require("@codama/visitors-core");
const { renderVisitor } = require("@codama/renderers-vixen-parser");

const projectName = "example-parser";
const idl = readJson(path.join(__dirname, "idl.json"));
const node = rootNodeFromAnchor(idl);

visit(
    node,
    renderVisitor({
        projectFolder: __dirname,
        projectName,
    }),
);
```

> **Tip:** The `projectName` is used for the Cargo crate name of the generated parser.

**Run the Code Generation Script**

```bash
node codama.cjs
```

Your folder structure should look like:

```
example-parser/
├── proto/
│   └── example_parser.proto
├── src/
│   ├── generated_parser/
│   ├── generated_sdk/
│   └── lib.rs
├── build.rs
├── Cargo.toml
├── codama.cjs
└── idl.json
```

**Build and Verify**

```bash
cargo build
```

If successful, you now have a working parser for Solana account data using Yellowstone Vixen.

#### Completion

Congratulations! You now have a custom Vixen parser ready for integration into a Vixen pipeline.


---

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