treelog 0.0.3

A customizable tree rendering library for Rust

Provides low-level and high-level APIs for rendering hierarchical data structures, similar to tree, npm ls, or cargo tree.

Installation • Quick Start • Documentation • Examples

Features

• Multiple Styles - Unicode, ASCII, Box drawing, and custom styles
• Builder API - Fluent interface for easy tree construction
• Iterator Support - Stream large trees without materializing
• Custom Formatters - Format nodes and leaves to your needs
• Optimized - Pre-computed prefixes and efficient rendering
• Zero Dependencies - Lightweight and fast

Installation

Add this to your Cargo.toml:

[dependencies]
treelog = "0.0.3"

Quick Start

use treelog::{Tree, renderer::write_tree};

let tree = Tree::Node("root".to_string(), vec![
    Tree::Leaf(vec!["item1".to_string()]),
    Tree::Node("sub".to_string(), vec![
        Tree::Leaf(vec!["subitem1".to_string()]),
        Tree::Leaf(vec!["subitem2".to_string()]),
    ]),
]);

let mut output = String::new();
write_tree(&mut output, &tree).unwrap();
println!("{}", output);

Output:

root
├─ item1
└─ sub
   ├─ subitem1
   └─ subitem2

Usage

Basic

use treelog::{Tree, renderer::write_tree};

let tree = Tree::Node("root".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]);
let mut output = String::new();
write_tree(&mut output, &tree).unwrap();
// root
//  └─ item

Builder API

use treelog::builder::TreeBuilder;

let mut builder = TreeBuilder::new();
builder.node("root").leaf("item1").node("sub").leaf("subitem1").leaf("subitem2").end().leaf("item2");
let tree = builder.build();
println!("{}", tree.render_to_string());

Low-Level API

use treelog::Tree;

let tree = Tree::Node("root".to_string(), vec![
    Tree::Leaf(vec!["line1".to_string(), "line2".to_string()]),
    Tree::Node("sub".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]),
]);
println!("{}", tree.render_to_string());

Iterator API

use treelog::{Tree, TreeIteratorExt};

let tree = Tree::Node("root".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]);

// Stream lines
for line in TreeIteratorExt::lines(&tree) {
    println!("{} {}", line.prefix, line.content);
}

// Or collect all at once
let lines: Vec<String> = tree.to_lines();

Customization

Styles:

use treelog::{Tree, TreeStyle, RenderConfig, StyleConfig};

let tree = Tree::Node("root".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]);

// Predefined styles
tree.render_to_string_with_config(&RenderConfig::default().with_style(TreeStyle::Ascii));

// Custom style
let style = StyleConfig::custom("├─", "└─", "│ ", "   ");
tree.render_to_string_with_config(&RenderConfig::default().with_style(style));

Formatters (requires formatters feature):

use treelog::{Tree, RenderConfig};

let tree = Tree::Node("root".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]);
let config = RenderConfig::default()
    .with_node_formatter(|label| format!("[{}]", label))
    .with_leaf_formatter(|line| format!("- {}", line));
tree.render_to_string_with_config(&config);

Streaming Large Trees

use treelog::{Tree, TreeIteratorExt};
use std::io::Write;

let tree = Tree::Node("root".to_string(), vec![Tree::Leaf(vec!["item".to_string()])]);
let mut stdout = std::io::stdout();
for line in TreeIteratorExt::lines(&tree) {
    writeln!(stdout, "{}{}", line.prefix, line.content).unwrap();
}

Performance

• Pre-computed prefixes - Efficient string buffer capacity estimation
• Iterator API - Stream large trees without materializing the entire structure
• Stack-based traversal - Memory-efficient tree walking

License

This project is licensed under the MIT License - see the LICENSE file for details.

Development

cargo fmt --all
cargo clippy --all-targets --all-features -- -D warnings
cargo test --all-features

Real-time feedback: This project includes VS Code/Cursor settings (.vscode/settings.json) that configure rust-analyzer to provide real-time feedback:

• Formatting: Automatically formats on save (matches cargo fmt)
• Clippy: Shows clippy warnings/errors as you type (matches pre-commit hook settings)
• Tests: Displays test failures in the editor

Git hooks available via pre-commit (see .pre-commit-config.yaml).

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.