Struct LineBuffer 

pub struct LineBuffer { /* private fields */ }

Text buffer with cursor tracking for line editing operations.

Manages the actual text being edited and the cursor position within it. Supports UTF-8 text and provides methods for character/word manipulation.

This struct is typically not used directly - instead use LineEditor which provides the high-level editing interface.

Implementations

impl LineBuffer

pub fn new(capacity: usize) -> Self

Creates a new line buffer with the specified capacity.

Arguments

• capacity - Initial capacity for the internal buffer in bytes

Examples

use editline::LineBuffer;

let buffer = LineBuffer::new(1024);
assert!(buffer.is_empty());

pub fn clear(&mut self)

Clears the buffer and resets the cursor to the start.

pub fn len(&self) -> usize

Returns the length of the buffer in bytes.

Note: For UTF-8 text, this is the byte count, not the character count.

pub fn is_empty(&self) -> bool

Returns true if the buffer is empty.

pub fn cursor_pos(&self) -> usize

Returns the current cursor position in bytes from the start.

pub fn as_str(&self) -> Result<&str>

Returns the buffer contents as a UTF-8 string slice.

Errors

Returns Err if the buffer contains invalid UTF-8.

pub fn as_bytes(&self) -> &[u8]

Returns the buffer contents as a byte slice.

pub fn insert_char(&mut self, c: char)

Inserts a character at the cursor position, moving the cursor forward.

Supports UTF-8 characters. The cursor advances by the byte length of the character.

pub fn delete_before_cursor(&mut self) -> bool

Deletes the character before the cursor (backspace operation).

Returns true if a character was deleted, false if the cursor is at the start.

pub fn delete_at_cursor(&mut self) -> bool

Deletes the character at the cursor (delete key operation).

Returns true if a character was deleted, false if the cursor is at the end.

pub fn move_cursor_left(&mut self) -> bool

Moves the cursor one position to the left.

Returns true if the cursor moved, false if already at the start.

pub fn move_cursor_right(&mut self) -> bool

Moves the cursor one position to the right.

Returns true if the cursor moved, false if already at the end.

pub fn move_cursor_to_start(&mut self) -> usize

Moves the cursor to the start of the line.

Returns the number of positions the cursor moved.

pub fn move_cursor_to_end(&mut self) -> usize

Moves the cursor to the end of the line.

Returns the number of positions the cursor moved.

pub fn move_cursor_word_left(&mut self) -> usize

Moves the cursor to the start of the previous word.

Words are defined as sequences of alphanumeric characters and underscores. Symbols (like +, -, *) are treated as separate words. Only whitespace is skipped when navigating between words.

Returns the number of positions the cursor moved.

pub fn move_cursor_word_right(&mut self) -> usize

Moves the cursor to the start of the next word.

Words are defined as sequences of alphanumeric characters and underscores. Symbols (like +, -, *) are treated as separate words. Only whitespace is skipped when navigating between words.

Returns the number of positions the cursor moved.

pub fn delete_word_left(&mut self) -> usize

Deletes the word to the left of the cursor (Alt+Backspace operation).

Returns the number of bytes deleted.

pub fn delete_word_right(&mut self) -> usize

Deletes the word to the right of the cursor (Ctrl+Delete operation).

Returns the number of bytes deleted.

pub fn load(&mut self, text: &str)

Loads text into the buffer, replacing existing content.

The cursor is positioned at the end of the loaded text. Used internally for history navigation.