Format Macros

The cformat! and cformatb! macros format text with Farben markup and return the result as a String. Think of them as format! with full markup support built in.

cformat!

Formats a string with Farben markup and appends a trailing reset.

use farben::prelude::*;

let name = "Farben";
let msg = cformat!("[bold green]Hello, {name}![/] Welcome.");
println!("{msg}");

Format Argument Styles

cformat! supports all the same argument styles as format!:

use farben::prelude::*;

// Positional arguments
let msg = cformat!("[red]{} and {}", "a", "b");

// Named arguments
let msg = cformat!("[green]{greeting}", greeting = "Hello");

// Implicit capture (Rust 1.58+)
let user = "Alice";
let msg = cformat!("[dim]{user} joined the server.");

// Format specifiers
let pi = 3.14159;
let msg = cformat!("[yellow]Pi is approximately {pi:.2}");

Bleed variant:

use farben::prelude::*;

let msg = cformatb!("[red]This style bleeds");
// No trailing reset appended. msg ends with the ANSI red code

When the compile Feature Is Enabled

With compile enabled, static markup segments in your format string are rendered to ANSI escape codes at compile time. Only the {...} argument placeholders are evaluated at runtime. This means the markup itself has zero runtime overhead.

[dependencies]
farben = { version = "...", features = ["compile"] }

use farben::prelude::*;

let user = "Alice";
// "[bold green]" is baked into the binary as ANSI codes at compile time
cprintln!("[bold green]{user} logged in.");

The {user} placeholder is the only part evaluated at runtime. The ANSI sequences for [bold green] are already in the binary as a static string literal.

cformat! vs cformatb!

Macro	Trailing Reset	Use Case
cformat!	Yes	Formatting a self-contained colored string
cformatb!	No	Formatting a string whose style bleeds into subsequent output

Replaces color_fmt!

The color_fmt! macro is deprecated in favor of cformat!. The new name is shorter and consistent with the cprint! / cprintln! naming convention.

// Old way (deprecated):
// let msg = color_fmt!("[red]Error: {err}");

// New way:
let msg = cformat!("[red]Error: {err}");

All Macros Using cformat!

Every macro in the c* family uses cformat! internally when the compile feature is enabled:

• cprint! / cprintln!
• cprintb! / cprintbln!
• ceprint! / ceprintln!
• ceprintb! / ceprintbln!
• cwrite! / cwriteln!
• cwriteb! / cwritebln!

This means enabling compile improves the performance of all of them, not just cformat!.