2. Markup and style¶

Tags¶

A tag names a style. Styles combine, and tags nest:

console.print_str("[bold]bold[/] [italic]italic[/] [underline]underline[/]");
console.print_str("[red]red[/] [white on blue]white on blue[/]");
console.print_str("[bold magenta]outer [italic]and inner[/] again outer[/]");

[bold]bold[/] [italic]italic[/] [underline]underline[/]
[red]red[/] [white on blue]white on blue[/]
[bold magenta]outer [italic]and inner[/] again outer[/]

[/] closes the most recent tag; [/bold] closes a named one. Both work, and abbreviations resolve — [b]…[/bold] matches, because tag names are normalised before they are compared.

What can go in a tag¶

Combine them freely: [bold not italic #ff8800 on grey15].

Styles as values¶

Markup is a convenience. The underlying type is Style:

use rich::{Console, Style, Text};

let console = Console::new();
let style = Style::parse("bold underline").unwrap();
console.print(&Text::styled("styled directly", style));

Automatic highlighting¶

A Console highlights recognisable things without being asked — numbers, paths, URLs, UUIDs, booleans, None:

This is on by default, matching upstream. Turn it off when the text is not code-like:

let console = Console::builder().highlight(false).build();

Themes¶

A theme maps names to styles. Because span styles are resolved when the text is rendered, not when it is created, changing the theme restyles output that was already built:

use rich::{Console, Style, Theme};

let mut theme = Theme::default_theme();
theme.insert("repr.number", Style::parse("bold red").unwrap());
// The same applies to your own names.
theme.insert("danger", Style::parse("bold white on red").unwrap());

let console = Console::builder().theme(theme).build();
console.print_str("answer = 42");     // 42 is bold red, not the default cyan
console.print_str("[danger] DANGER [/]");

Theme::from_styles builds a theme from (name, style) pairs, like upstream's Theme({...}): with inherit set, the default styles come first.

Temporary themes¶

A console keeps a stack of themes, as upstream's does. use_theme pushes one until the returned guard is dropped; print through the guard while it lives:

use rich::{Console, Theme};

let mut console = Console::new();
let alert = Theme::from_styles([("danger", "bold yellow on red")], false).unwrap();
{
    let themed = console.use_theme(alert);   // inherits the current styles
    themed.print_str("[danger] ALERT [/] answer = 42");
}                                            // popped here, even on panic
console.print_str("[danger]back to normal[/]");

push_theme(theme, inherit) and pop_theme() are the manual form; popping the base theme is an error, as upstream's ThemeStackError is.

Theme files¶

Upstream's theme files ([styles] sections read by Python's configparser) load unchanged, so a theme shared with Python rich users works here too:

[styles]
danger = bold white on red
repr.number = bold magenta

let theme = rich::Theme::read("my-theme.ini", true)?; // inherit the defaults
println!("{}", theme.config());                       // write one back out

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