tabled

An easy to use library for pretty printing tables of Rust structs and enums.

Agenda

• Usage
  • Derive information
• Style
  • Styles
    • Default
    • Psql
    • GithubMarkdown
    • Pseudo
    • PseudoClean
    • Noborder
  • Custom Style
  • Alignment
  • Format
  • Indent
  • Disable
  • Color
• Features
  • Column name override
  • Hide a column
  • Custom field formatting
  • Tuple combination
  • Object
• Notes
  • Emoji

Usage

To print a list of structs or enums as a table your types should implement the the Tabled trait or derive with a #[derive(Tabled)] macro.

use tabled::{Tabled, Table};

#[derive(Tabled)]
struct Language {
    name: &'static str,
    designed_by: &'static str,
    invented_year: usize,
}

let languages = vec![
    Language{
        name: "C",
        designed_by: "Dennis Ritchie",
        invented_year: 1972
    },
    Language{
        name: "Rust",
        designed_by: "Graydon Hoare",
        invented_year: 2010
    },
    Language{
        name: "Go",
        designed_by: "Rob Pike",
        invented_year: 2009
    },
];

let table = Table::new(languages).to_string();

let expected = "+------+----------------+---------------+\n\
                | name |  designed_by   | invented_year |\n\
                +------+----------------+---------------+\n\
                |  C   | Dennis Ritchie |     1972      |\n\
                +------+----------------+---------------+\n\
                | Rust | Graydon Hoare  |     2010      |\n\
                +------+----------------+---------------+\n\
                |  Go  |    Rob Pike    |     2009      |\n\
                +------+----------------+---------------+\n";

assert_eq!(table, expected);

Derive information

To be able to use a Tabled macro each field should implement std::fmt::Display otherwise it will not work.

The following example will cause a error.

use tabled::Tabled;
#[derive(Tabled)]
struct SomeType {
    field1: SomeOtherType,
}

struct SomeOtherType;

Most of the default types implements the trait out of the box.

use tabled::Table;
let some_numbers = [1, 2, 3];
let table = Table::new(&some_numbers);

Style

Styles

A list of ready to use styles. Styles can be chosen by passing a Style argument option.

let table = Table::new(&data).with(Style::psql());

Default

+------+----------------+---------------+
| name |  designed_by   | invented_year |
+------+----------------+---------------+
|  C   | Dennis Ritchie |     1972      |
+------+----------------+---------------+
| Rust | Graydon Hoare  |     2010      |
+------+----------------+---------------+
|  Go  |    Rob Pike    |     2009      |
+------+----------------+---------------+

Psql

 name |  designed_by   | invented_year 
------+----------------+---------------
  C   | Dennis Ritchie |     1972      
 Rust | Graydon Hoare  |     2010      
  Go  |    Rob Pike    |     2009      

GithubMarkdown

| name |  designed_by   | invented_year |
|------+----------------+---------------|
|  C   | Dennis Ritchie |     1972      |
| Rust | Graydon Hoare  |     2010      |
|  Go  |    Rob Pike    |     2009      |

Pseudo

┌──────┬────────────────┬───────────────┐
│ name │  designed_by   │ invented_year │
├──────┼────────────────┼───────────────┤
│  C   │ Dennis Ritchie │     1972      │
├──────┼────────────────┼───────────────┤
│ Rust │ Graydon Hoare  │     2010      │
├──────┼────────────────┼───────────────┤
│  Go  │    Rob Pike    │     2009      │
└──────┴────────────────┴───────────────┘

PseudoClean

┌──────┬────────────────┬───────────────┐
│ name │  designed_by   │ invented_year │
├──────┼────────────────┼───────────────┤
│  C   │ Dennis Ritchie │     1972      │
│ Rust │ Graydon Hoare  │     2010      │
│  Go  │    Rob Pike    │     2009      │
└──────┴────────────────┴───────────────┘

Noborder

 name    designed_by     invented_year 
  C     Dennis Ritchie       1972      
  Rust   Graydon Hoare       2010      
  Go       Rob Pike          2009      

Custom Style

You can modify existing styles to fits your needs.

let style = tabled::Style::noborder()
                .frame_bottom(Some(Line::short('*', ' '')))
                .split(Some(Line::short(' ', ' ')))
                .inner(' ');

let table = Table::new(&data).with(style);

Alignment

You can set a horizontal and vertical alignment for a Header, Column, Row or Full set of cells.

Table::new(&data)
    .with(Modify::new(Full)
        .with(Alignment::left())
        .with(Alignment::top())
    );

Format

The Format function provides an interface for a modification of cells.

Table::new(&data)
    .with(Style::psql()),
    .with(Modify::new(Column(..)).with(Format(|s| format!("<< {} >>", s))))
    .with(Modify::new(Row(..1)).with(Format(|s| format!("Head {}", s))));

It's also possible to use functions with signature Fn(&str) -> String as a formatter.

Table::new(&data)
    .with(Style::psql()),
    .with(Modify::new(Column(..)).with(|s: &str| format!("<< {} >>", s)))
    .with(Modify::new(Row(..1)).with(str::to_lowercase));

IMPORTANT: you may need to specify type in your lambda otherwise compiler may be disagreed to work :)

Indent

The Indent type provides an interface for a left, right, top and bottom indent of cells.

Table::new(&data).with(Modify::new(Row(1..)).with(Indent::new(1, 1, 0, 2)));

Disable

You can remove certain rows or columns from the table.

Table::new(&data)
    .with(Disable::Row(..1))
    .with(Disable::Column(3..4));

Color

The library doesn't bind you in usage of any color library but to be able to work corectly with color input you should provide a --features color.

Table::new(&data)
    .with(Style::psql())
    .with(Modify::new(Column(..1)).with(Format(|s| s.red().to_string())))
    .with(Modify::new(Column(1..2)).with(Format(|s| s.blue().to_string())))
    .with(Modify::new(Column(2..)).with(Format(|s| s.green().to_string())));

Features

Column name override

You can use a #[header("")] attribute to override a column name.

#[derive(Tabled)]
struct Person {
    #[header("Name")]
    first_name: &'static str,
    #[header("Surname")]
    last_name: &'static str,
}

Hide a column

You can mark filds as hidden in which case they fill be ignored and not be present on a sheet.

A similar affect could be achived by the means of a Disable setting.

struct Person {
   #[header(hidden = true)]
   id: u8,
   #[header("field 2", hidden)]
   number: &'static str,
   name: &'static str,
}

Custom field formatting

#[derive(Tabled)] is possible only when all fields implement a Display trait.

However, this may be often not the case for example when a field uses the Option type.

There's 2 common ways how to solve this:

• Implement Tabled trait manually for a type.
• Wrap Option to something like DisplayedOption(Option) and implement a Display trait for it.

Or to use an attribute #[field(display_with = "func")] for the field. To use it you must provide a function name in a display_with parameter.

fn display_option(o: &Option<bool>) -> String {
    match o {
        Some(s) => format!("is valid thing = {}", s), 
        None => format!("is not valid"),
    }
}

#[derive(Tabled)]
pub struct MyRecord {
    pub id: i64,
    #[field(display_with="display_option")]
    pub valid: Option<bool>
}

Tuple combination

You also can combine objets which implements Tabled by means of tuples, you will get a combined columns of them.

use tabled::{Tabled, Table, Style};

#[derive(Tabled)]
enum Domain {
    Security,
    Embeded,
    Frontend,
    Unknown,
}

#[derive(Tabled)]
struct Developer(#[header("name")] &'static str);

let data = vec![
    (Developer("Terri Kshlerin"), Domain::Embeded),
    (Developer("Catalina Dicki"), Domain::Security),
    (Developer("Jennie Schmeler"), Domain::Frontend),
    (Developer("Maxim Zhiburt"), Domain::Unknown),
];

let table = Table::new(data).with(Style::psql()).to_string();

assert_eq!(
    table,
    concat!(
        "      name       | Security | Embeded | Frontend | Unknown \n",
        "-----------------+----------+---------+----------+---------\n",
        " Terri Kshlerin  |          |    +    |          |         \n",
        " Catalina Dicki  |    +     |         |          |         \n",
        " Jennie Schmeler |          |         |    +     |         \n",
        "  Maxim Zhiburt  |          |         |          |    +    \n"
    )
);

Object

You can peak your target for settings using and and not methods for an object.

Full.not(Row(..1)) // peak all cells except header
Head.and(Column(..1)).not(Cell(0, 0)) // peak a header and first column except a (0, 0) cell

Notes

Emoji

The library support emojies out of the box but be aware that some of the terminals and editors may not render them as you would expect.

Let's add emojies to an example from a Usage section.

 let languages = vec![
     Language {
         name: "C 💕",
         designed_by: "Dennis Ritchie",
         invented_year: 1972,
     },
     Language {
         name: "Rust 👍",
         designed_by: "Graydon Hoare",
         invented_year: 2010,
     },
     Language {
         name: "Go 🧋",
         designed_by: "Rob Pike",
         invented_year: 2009,
     },
 ];

The resultant table will look like the following.

As you can see Github triks a bit a return table, but GNOME terminal and Alacritty terminal handles it correctly.

+---------+----------------+---------------+
|  name   |  designed_by   | invented_year |
+---------+----------------+---------------+
|  C 💕   | Dennis Ritchie |     1972      |
+---------+----------------+---------------+
| Rust 👍 | Graydon Hoare  |     2010      |
+---------+----------------+---------------+
|  Go 🧋  |    Rob Pike    |     2009      |
+---------+----------------+---------------+