psource

print source code

CLI tool to pretty print source code to stdout or directly to the clipboard.

The tool is created to quickly provide source code context to a large language model (LLM).

Roadmap

• Print to stdout

• Copy to clipboard

• Skip binary files

• Configuration file entry to toggle direct output to clipboard by default

• Add cargo build CI/CD

• Publish to crates.io

• Add CI/CD to publish to crates.io

• Publish package to the AUR

• Add CI/CD to publish package to the AUR

• Include only files matching a regex

• Exclude files matching a regex

• Add tests

• Add cargo test CI/CD

• Make async

• Ability to omit comments in output

• Add option to print as markdown fenced code blocks, e.g.:

      **src/main.rs:**
      ```rust
      fn main() {
          println!("Hello, world!");
      }
      ```
  

• Add video/gif demo to README.md

Install

Install using Cargo

Make sure to have Cargo installed and PATH configured. See The Rust Programming Language - Installing Binaries with cargo install.

Install from crates.io

cargo install psource

Install from GitHub source

cargo install --git https://github.com/frederikstroem/psource.git

Install from local source

cargo install --path .

Quick start

Get help:

psource --help
CLI tool to pretty print source code to stdout or directly to the clipboard. Skips binary files.

Usage: psource [OPTIONS] [INPUT]...

Arguments:
  [INPUT]...  Input files and directories

Options:
  -s, --stdout   Print the source code to stdout
  -c, --copy     Copy the source code to the clipboard
  -h, --help     Print help
  -V, --version  Print version

Configuration

The tool can be configured using a configuration file. The configuration file is a simple TOML file with the following structure:

# Copy the source code to the clipboard instead of printing it to stdout (default: false)
clipboard_is_default_output_target = false

psource will look for a configuration file in the following $HOME/.config/psource/config.toml.

Example: Add a to_uppercase utils function to a Rust project

We have created a simple Rust project with a lib.rs file and a main.rs file.

main.rs:

mod lib;

fn main() {
    let message = lib::greet("Rustacean");
    println!("{}", message);
}

lib.rs:

pub fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

We want to add a to_uppercase function to a new utils.rs file and use it in lib.rs. We can use the psource tool to quickly copy the relevant code to the clipboard.

cd into the project root directory and run:

psource -c src

This command will place the following content onto your clipboard:

⚫ simple_rust_program/src/main.rs
mod lib;

fn main() {
    let message = lib::greet("Rustacean");
    println!("{}", message);
}

⚫ simple_rust_program/src/lib.rs
pub fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

You can now prompt the LLM with the following:

Please add a to_uppercase function to a new utils.rs file. Modify the greet function in lib.rs to use the to_uppercase function.

Source code:

⚫ simple_rust_program/src/main.rs
mod lib;

fn main() {
    let message = lib::greet("Rustacean");
    println!("{}", message);
}

⚫ simple_rust_program/src/lib.rs
pub fn greet(name: &str) -> String {
    format!("Hello, {}!", name)
}

The LLM should be able to help you complete the task.

Note: This is a very simple example but scales really well to large projects. The limit largely depends on the LLM's capabilities and its context window. I've had great success with OpenAI's GPT-4 Turbo, used with an alternative front-end utilizing the API, I can recommend chatgpt-web. GPT-4 Turbo has a context window of 128,000 tokens, and I've also found setting a sample temperature of ±0.6 to work well for code development tasks.

Tip: A file tree structure can sometimes help the LLM to better understand the context of the code. For such a task, I recommend using eza with the --tree option. To pipe it to the clipboard, a tool like xsel can be used, e.g., eza --tree | xsel -b.

Speeding up the copy to clipboard process

Due to a bug in the software supply chain, the -c option requires psource to wait for some time before exiting, else the clipboard will not be updated on some systems (discovered on KDE Plasma running X11).[1][2] To speed up the process, the psource stdout can be piped to a clipboard tool like xsel, e.g., psource src | xsel -b.