# Developer's Guide
## Incrementing the Version
The following instructions will guide you to incrementing the Carlo language
version number.
1. Open `src/main.rs`. Change the `VERSION` string to the new version number.
2. Open `Cargo.toml`. Change the version number towards the top of the file.
## Adding a Subcommand
The following instructions will guide you to adding a Carlo langauge subcommand.
1. Create a Cargo library package in the `subcommands` directory with the name `sc`, where `sc` is your desired subcommand name.
2. Create a function in your subcommand library named `sc::sc`. It is recommended that you import `carlotk::prelude::*` so you can use the Carlo tokenizer, parser, and environment utilities. Your function must have the following signature: `fn(CliArgs) -> ()`.
3. Create the following entry in `Cargo.toml`.
```
[dependencies.sc]
path = "./subcommands/sc"
```
4. In `src/main.rs`, add `subcommand sc` (on a new line) to the `include_subcommands!` macro invocation.