Crate multiline_input 

Multiline terminal input with rich editing capabilities

This crate provides a simple way to collect multiline text input from the terminal with intuitive key bindings:

• ENTER to submit
• CTRL+ENTER or SHIFT+ENTER to insert newline
• ESC or CTRL+C to cancel

Quick Start

use multiline_input::collect;

match collect("Enter your message:") {
  Ok(Some(text)) => println!("You entered: {}", text),
  Ok(None) => println!("Cancelled"),
  Err(e) => eprintln!("Error: {}", e),
}

Advanced Usage with Builder

use multiline_input::Builder;

let editor = Builder::new()
  .prompt("Enter commit message:")
  .min_length(10)
  .show_line_numbers(true)
  .show_status(true)
  .build();

match editor.collect() {
  Ok(Some(msg)) => println!("Commit: {}", msg),
  Ok(None) => println!("Cancelled"),
  Err(e) => eprintln!("Error: {}", e),
}

Key Bindings

Key	Action
ENTER	Submit input
CTRL+ENTER	Insert newline
SHIFT+ENTER	Insert newline
ESC	Cancel
CTRL+C	Cancel
Backspace	Delete before cursor
Delete	Delete at cursor
Arrow keys	Move cursor
Home/End	Move to line start/end
CTRL+Home/End	Move to text start/end

Testing

This crate uses trait-based dependency injection for testability. The TerminalOps trait abstracts all terminal operations, allowing tests to use MockTerminal instead of real terminal I/O.

Test Quality Guarantees

• Non-Fragile: All tests use MockTerminal with explicit configuration
• Deterministic: Pre-programmed key sequences ensure consistent results
• No Environment Dependencies: Tests never interact with actual terminal
• Fast: Integration tests run instantly (no waiting for user input)

Test Organization

Tests are organized by functional domain in the tests/ directory:

• buffer_operations_test.rs - Text buffer operations
• key_handling_test.rs - Key event parsing and action mapping
• integration_workflows_test.rs - End-to-end workflows
• error_paths_test.rs - Error handling (NoTty, TerminalTooSmall)
• validation_test.rs - Input validation logic
• builder_config_test.rs - Builder pattern and configuration

Total: 44 tests with 100% pass rate

Example Test with MockTerminal

use multiline_input::Builder;
// Note: MockTerminal is in tests/common/mock_terminal.rs

#[test]
fn test_basic_input() {
  let mut terminal = MockTerminal::new(true, (80, 24));
  terminal.push_key(key(KeyCode::Char('h'), KeyModifiers::NONE));
  terminal.push_key(key(KeyCode::Char('i'), KeyModifiers::NONE));
  terminal.push_key(key(KeyCode::Enter, KeyModifiers::NONE));

  let editor = Builder::new()
    .prompt("Input:")
    .build_with(terminal);

  let result = editor.collect();
  assert_eq!(result.unwrap(), Some("hi".to_string()));
}

See tests/readme.md for complete test documentation and examples.

Re-exports

pub use builder::Builder;

pub use editor::Editor;

pub use error::Error;

Modules

builder

Builder pattern for configuring multiline editor

editor

Main editor logic for multiline input collection

error

Error types for multiline input collection

Functions

collect

Collect multiline input from terminal

collect_validated

Collect input with validation