#shell #commandline #table #unicode

comfy-table

An easy to use library for building beautiful tables with automatic content wrapping

26 releases (17 stable)

4.1.1 Aug 11, 2021
4.0.1 Jul 8, 2021
3.0.0 Jun 13, 2021
2.1.0 Jan 26, 2021
0.1.0 Mar 21, 2020

#9 in Text processing

Download history 6751/week @ 2021-07-03 4806/week @ 2021-07-10 5290/week @ 2021-07-17 4828/week @ 2021-07-24 7674/week @ 2021-07-31 7747/week @ 2021-08-07 9305/week @ 2021-08-14 10231/week @ 2021-08-21 10791/week @ 2021-08-28 8544/week @ 2021-09-04 9919/week @ 2021-09-11 9688/week @ 2021-09-18 9249/week @ 2021-09-25 9273/week @ 2021-10-02 10181/week @ 2021-10-09 10745/week @ 2021-10-16

22,793 downloads per month
Used in 36 crates (27 directly)

MIT license

120KB
1.5K SLoC

Comfy-table

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comfy-table

Comfy-table is designed as a library for building beautiful tables, while being easy to use.

Features

  • Dynamic arrangement of content depending on a given width.
  • ANSI content styling for terminals (Colors, Bold, Blinking, etc.).
  • Styling Presets and preset modifiers to get you started.
  • Pretty much every part of the table is customizable (borders, lines, padding, alignment).
  • Constraints on columns that allow some additional control over how to arrange content.
  • Cross plattform (Linux, macOS, Windows).
  • It's FAST! Benchmarks show that a pretty big table with weird constraints is build in 4 μs, which is 4*1e^6. To run the benchmarks install criterion via cargo install cargo-criterion and run cargo criterion afterwards.

Comfy-table is written for the current stable Rust version. Older Rust versions may work, but aren't officially supported.

Examples

use comfy_table::Table;

fn main() {
    let mut table = Table::new();
    table
        .set_header(vec!["Header1", "Header2", "Header3"])
        .add_row(vec![
                 "This is a text",
                 "This is another text",
                 "This is the third text",
        ])
        .add_row(vec![
                 "This is another text",
                 "Now\nadd some\nmulti line stuff",
                 "This is awesome",
        ]);

    println!("{}", table);
}

Create a very basic table.
This table will become as wide as your content, nothing fancy happening here.

+----------------------+----------------------+------------------------+
| Header1              | Header2              | Header3                |
+======================================================================+
| This is a text       | This is another text | This is the third text |
|----------------------+----------------------+------------------------|
| This is another text | Now                  | This is awesome        |
|                      | add some             |                        |
|                      | multi line stuff     |                        |
+----------------------+----------------------+------------------------+

More Features

use comfy_table::*;
use comfy_table::presets::UTF8_FULL;
use comfy_table::modifiers::UTF8_ROUND_CORNERS;

fn main() {
    let mut table = Table::new();
    table
        .load_preset(UTF8_FULL)
        .apply_modifier(UTF8_ROUND_CORNERS)
        .set_content_arrangement(ContentArrangement::Dynamic)
        .set_table_width(40)
        .set_header(vec!["Header1", "Header2", "Header3"])
        .add_row(vec![
                 Cell::new("Center aligned").set_alignment(CellAlignment::Center),
                 Cell::new("This is another text"),
                 Cell::new("This is the third text"),
        ])
        .add_row(vec![
                 "This is another text",
                 "Now\nadd some\nmulti line stuff",
                 "This is awesome",
        ]);

    // Set the default alignment for the third column to right
    let column = table.get_column_mut(2).expect("Our table has three columns");
    column.set_cell_alignment(CellAlignment::Right);

    println!("{}", table);
}

Create a table with UTF8 styling, and apply a modifier that gives the table round corners.
Additionally, the content will dynamically wrap to maintain a given table width.
If the table width isn't explicitely set and the program runs in a terminal, the terminal size will be used.

On top of this, we set the default alignment for the right column to Right and the alignment of the left top cell to Center.

╭────────────┬────────────┬────────────╮
│ Header1    ┆ Header2    ┆    Header3 │
╞════════════╪════════════╪════════════╡
│  This is a ┆ This is    ┆    This is │
│    text    ┆ another    ┆  the third │
│            ┆ text       ┆       text │
├╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┼╌╌╌╌╌╌╌╌╌╌╌╌┤
│ This is    ┆ Now        ┆    This is │
│ another    ┆ add some   ┆    awesome │
│ text       ┆ multi line ┆            │
│            ┆ stuff      ┆            │
╰────────────┴────────────┴────────────╯

Styling

use comfy_table::*;
use comfy_table::presets::UTF8_FULL;

fn main() {
    let mut table = Table::new();
    table.load_preset(UTF8_FULL)
        .set_content_arrangement(ContentArrangement::Dynamic)
        .set_table_width(80)
        .set_header(vec![
                    Cell::new("Header1").add_attribute(Attribute::Bold),
                    Cell::new("Header2").fg(Color::Green),
                    Cell::new("Header3"),
        ])
        .add_row(vec![
                 Cell::new("This is a bold text").add_attribute(Attribute::Bold),
                 Cell::new("This is a green text").fg(Color::Green),
                 Cell::new("This one has black background").bg(Color::Black),
        ])
        .add_row(vec![
                 Cell::new("Blinky boi").add_attribute(Attribute::SlowBlink),
                 Cell::new("This table's content is dynamically arranged. The table is exactly 80 characters wide.\nHere comes a reallylongwordthatshoulddynamicallywrap"),
                 Cell::new("COMBINE ALL THE THINGS")
                 .fg(Color::Green)
                 .bg(Color::Black)
                 .add_attributes(vec![
                                 Attribute::Bold,
                                 Attribute::SlowBlink,
                 ])
        ]);

    println!("{}", table);
}

This code generates the table that can be seen at the top of this document.

Code Examples

A few examples can be found in the example folder. To test an example, run it with cargo run --example $name. E.g.:

cargo run --example readme_table

If you're looking for more information, take a look at the tests folder.
There are tests for almost every feature including a visual view for each resulting table.

Contribution Guidelines

Comfy-table is supposed to be minimalistic. A fixed set of features that just work, for a simple use-case:

  • Normal tables (columns, rows, one cell per column/row).
  • Dynamic arrangement of content to a given width.
  • Some kind of manual intervention in the arrangement process.

If you come up with an idea or an improvement, that fits into the current scope of the project, feel free to create an issue :)!

Some things however will most likely not be added to the project, since they drastically increase the complexity of the library or cover very specific edge-cases.

Such features are:

  • Nested tables
  • Cells that span over multiple columns/rows
  • CSV to table conversion and vice versa

Unsafe

Comfy-table doesn't allow unsafe code in its code-base. As it's a "simple" formatting library, it also shouldn't be needed in the future.

However, Comfy-table uses two unsafe functions calls in its dependencies.
Both calls can be disabled by explicitely calling Table::force_no_tty.

  1. crossterm::tty::IsTty. This function is necessary to detect whether we're currently on a tty or not. This is only called if no explicit width is provided via Table::set_table_width.

    /// On unix, the `isatty()` function returns true if a file
    /// descriptor is a terminal.
    #[cfg(unix)]
    impl<S: AsRawFd> IsTty for S {
        fn is_tty(&self) -> bool {
            let fd = self.as_raw_fd();
            unsafe { libc::isatty(fd) == 1 }
        }
    }
    
  2. crossterm::terminal::size. This function is necessary to detect the current terminal width, if we're on a tty. This is only called if no explicit width is provided via Table::set_table_width.

    http://rosettacode.org/wiki/Terminal_control/Dimensions#Library:_BSD_libc This is another libc call with, which is used to communicate with /dev/tty via a file descriptor.

    ...
    if wrap_with_result(unsafe { ioctl(fd, TIOCGWINSZ.into(), &mut size) }).is_ok() {
        Ok((size.ws_col, size.ws_row))
    } else {
        tput_size().ok_or_else(|| std::io::Error::last_os_error().into())
    }
    ...
    

Dependencies

~0.8–1.7MB
~34K SLoC