Adding `print_break` library as a dependency

Run this command in a terminal, in your project's directory:

cargo add print-break

To add it manually, edit your project's Cargo.toml file and add to the [dependencies] section:

print-break = "0.2.2"

The print_break library will be automatically available globally. Read the print_break library documentation.

Back to the crate overview.

Readme

print-break

A simple Rust debugging macro that pretty-prints variables and pauses execution. No debugger needed.

Features

Pretty-prints any Debug type with syntax highlighting
Auto-detects JSON, TOML, YAML strings and formats them with colors
Pauses execution until you press Enter
Compiles to nothing in release builds - zero overhead in production
Disable at runtime with PRINT_BREAK=0
Interactive controls: continue, quit, skip, more, help
Stack traces - press t to see how you got there
Clipboard support - press c to copy values
Elapsed time - see time between breakpoints
Conditional breakpoints with print_break_if!
Non-TTY safe - won't hang in CI/piped output
Customizable borders - rounded, sharp, double, or ASCII

Installation

[dependencies]
print-break = "0.1"

Usage

use print_break::{print_break, print_break_if};

fn main() {
    let user_id = 42;
    let name = "ferris";
    let items = vec![1, 2, 3];

    // Basic breakpoint
    print_break!(user_id, name, items);

    // Conditional breakpoint (great for loops)
    for i in 0..100 {
        print_break_if!(i == 50, i);
    }

    // JSON strings are auto-formatted
    let json = r#"{"status": "ok", "data": [1, 2, 3]}"#;
    print_break!(json);
}

Output

┌─ BREAK #1 ─────────────────────────────────────
│ src/main.rs:8                                  │
├────────────────────────────────────────────────
│ user_id = 42
│ name = "ferris"
│ items = [1, 2, 3]
└────────────────────────────────────────────────
[Enter=continue, m=more, s=skip all, q=quit]

Interactive Controls

When paused at a breakpoint:

Key	Action
Enter	Continue to next breakpoint
m	Show full output (if truncated)
t	Show stack trace
c	Copy value to clipboard
s	Skip all remaining breakpoints
q	Quit the program
h / ?	Show help

Environment Variables

# Disable all breakpoints
PRINT_BREAK=0 cargo run

# Re-enable (default)
PRINT_BREAK=1 cargo run

# Set max nesting depth for structs (default: 4)
PRINT_BREAK_DEPTH=6 cargo run

# Show all nesting (no collapse)
PRINT_BREAK_DEPTH=999 cargo run

# Border styles: rounded (default), sharp, double, ascii
PRINT_BREAK_STYLE=double cargo run
PRINT_BREAK_STYLE=ascii cargo run

CI / Non-Interactive Mode

When stderr is not a TTY (piped to file, running in CI), print-break automatically:

Disables colors
Skips the pause (won't hang your CI)
Still prints the debug output for logging

Conditional Breakpoints

Perfect for debugging loops:

use print_break::print_break_if;

for i in 0..1000 {
    // Only break when i is 500
    print_break_if!(i == 500, i);

    // Break when condition is met
    print_break_if!(some_value > threshold, some_value, threshold);
}

Release Builds

In release builds (cargo build --release), all print_break! and print_break_if! calls compile to nothing - zero runtime overhead.

Format Detection

Strings are automatically detected and pretty-printed:

JSON - Objects and arrays
TOML - Configuration files
YAML - Configuration files
Plain text - Word-wrapped at 80 characters

Long output is truncated at 50 lines. Press m to see the full output.

Editor Integration

Neovim

Copy editors/nvim/print-break.lua to your Neovim config:

cp editors/nvim/print-break.lua ~/.config/nvim/after/plugin/

Keybindings (Rust files only):

Key	Mode	Action
`<leader>pb`	Normal	Insert `print_break!()` with word under cursor
`<leader>pb`	Visual	Wrap selection in `print_break!()`
`<leader>pB`	Normal	Insert `print_break_if!(condition, vars)`
`<leader>pc`	Normal	Remove all `print_break!` from current buffer
`<leader>pC`	Normal	Remove all `print_break!` from all Rust files

Smart features:

Automatically captures the variable under cursor
Appends to existing print_break! if one exists on the next line
Finds end of multi-line statements before inserting

License

MIT

Adding print_break library as a dependency

Adding `print_break` library as a dependency