nestable

A small Rust library for rendering text tables in the terminal.

Supports:

• multi-line cells
• Unicode (including emoji)
• ANSI styling (colours, bold, etc.)
• nested tables (via pre-rendering)

Command Line Utility

Despite being mostly developed as a rust library with minimal ddependencies, it also provides a nestable command line tool which can render CSV inputs from stdin and can be used as follows:

cat file.cvs | nestable

This provides incredibly limited functionality at the moment will be fleshed out with a proper implementation of RFC-4180 at a later point.

Library Example

use nestable::Table;

fn main() {
	#[rustfmt::skip]
	let table = nestable::Table::new([
		["Language", "Text"],
		["English", "nestable\nrendering tables\nacross multiple lines"],
		["Japanese", "ネスタブル\n複数行にわたる\nテーブル表示 🙂"],
		["Chinese\n(Simplified)", "可嵌套表格\n支持多行文本\n终端显示"],
		["Korean", "중첩 가능한 테이블\n여러 줄 텍스트\n터미널 출력"],
		["Persian", "جداول تو در تو\nمتن چند خطی\nخروجی ترمینال"],
		["Sanskrit", "नेस्टेबल टेबल्स\nबहुपङ्क्तिः पाठः\nटर्मिनल आउटपुट"],
	]);

	let cwd = std::env::current_dir()
		.map(|p| p.to_string_lossy().to_string())
		.unwrap_or_else(|_| "<unknown>".to_string());

	let user = std::env::var("USER")
		.map(|p| p.to_string())
		.unwrap_or_else(|_| "<unknown>".to_string());

	let system = nestable::Table::new([
		["Property", "Value"],
		["OS", std::env::consts::OS],
		["Architecture", std::env::consts::ARCH],
		["Directory", &cwd],
		["User", &user],
	]);

	let nested = nestable::Table::with_style( &styles::GLYPHS_ROUNDED, true, [
		vec!["System Details", "Unicode Demo"],
		vec![&system.to_string(), &table.to_string()],
	]);

	print!("{}", nested);
}

Example output:

Design

This crate uses a simple two-phase approach:

1. Input model Rows are defined as collections of strings.

2. Layout model Cells are split into lines, widths are computed, and a layout is derived before rendering.

Rendering is then performed from the computed layout.

ANSI handling

• ANSI escape sequences are preserved in output
• Display width is calculated while ignoring ANSI sequences
• Non-SGR escape sequences are not supported and may be ignored or warned about

Nested tables

Nested tables are supported by rendering them to strings:

["outer", &inner.to_string()]

This keeps the implementation simple and predictable.

Note: nested tables are rendered independently and are not resized based on the outer table.

Limitations

• No automatic text wrapping
• Layout is content-driven (columns expand to fit content)
• No column/row alignment options (yet)
• No true column spanning (only implicit “fill to end” behaviour)
• ANSI parsing is minimal (focused on common styling sequences)

Styling

Several predefined styles are available:

• GLYPHS_ROUNDED
• GLYPHS_SQUARE
• GLYPHS_NO_BORDER
• GLYPHS_NO_ROW_SEPARATOR
• ASCII_BORDER
• ASCII_NO_BORDER
• ASCII_NO_ROW_SEPARATOR

Optionally, the first row can be inverted.

Example:

use nestable::{Table, styles};

let table = Table::with_style(styles::GLYPHS_ROUNDED, false, [
    ["a", "b"],
    ["c", "d"],
]);

println!("{}", table);

Demo

There is a demo to be found in examples/demo.rs. To build and run it, use:

cargo run --example demo

License

MIT

Author

Charles Yates a link

Contributing / Feedback

Questions, suggestions, and bug reports are welcome via GitLab issues.