Struct IndentUnit 

pub struct IndentUnit {
    pub width: u8,
    pub expand_tabs: bool,
    pub tabstop: u8,
}

One level of indentation, resolved for a specific buffer.

width is shiftwidth — columns per indent level. tabstop is the display width of a literal tab byte. They are deliberately separate: conflating them means “change my indent size” silently reflows every file containing a hard tab, including content the user never edited.

Fields

width: u8

shiftwidth — columns added or removed per indent level. Clamped to at least 1 at use; a zero-width level would make > a no-op and columns → levels a division by zero.

expand_tabs: bool

expandtab — render indentation as spaces rather than tabs.

tabstop: u8

tabstop — display columns a literal tab advances to. Clamped to at least 1 at use.

Implementations

impl IndentUnit

pub fn new(width: u8, expand_tabs: bool, tabstop: u8) -> Self

Build a unit from raw option values: shiftwidth, expandtab, tabstop. Zero widths are stored as given and floored to 1 by Self::step / Self::tab_width.

pub fn step(&self) -> u16

shiftwidth, floored at 1. See Self::width.

pub fn tab_width(&self) -> u16

tabstop, floored at 1. See Self::tabstop.

pub fn indent_len(line: &str) -> usize

Byte length of line’s leading whitespace run.

Whitespace here is space and tab only — not \r, and not Unicode space separators. A line that is entirely whitespace returns its full length.

pub fn columns_of(&self, line: &str) -> u16

Display columns occupied by line’s leading whitespace.

A tab advances to the next multiple of tabstop, which is why this cannot be a byte count: "\t" and " " are the same indent at tabstop=4 and must compare equal.

pub fn render(&self, columns: u16) -> String

The whitespace string that renders as columns display columns.

With expandtab off this is tabs plus a space remainder, which is what vim produces and what keeps shiftwidth values that are not multiples of tabstop representable.

pub fn shift(&self, columns: u16, levels: i32) -> u16

columns shifted by levels indent steps, clamped at zero.

pub fn is_blank(line: &str) -> bool

Whether line has no non-whitespace content.

Blank lines are skipped by > / <: vim does not indent them, and doing so leaves trailing whitespace on lines the user never typed into.

pub fn reindented_prefix( &self, line: &str, levels: i32, ) -> Option<(usize, String)>

The replacement leading-whitespace for line shifted by levels, or None when nothing should change.

None covers both “blank line” and “the rendered result is byte-identical to what is already there” — the second matters because emitting a no-op edit still costs an undo entry and a render invalidation.

Trait Implementations

impl Clone for IndentUnit

fn clone(&self) -> IndentUnit

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for IndentUnit

impl Debug for IndentUnit

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for IndentUnit

fn default() -> Self

Matches the registered option defaults (shiftwidth=4, expandtab, tabstop=4) so a context that never resolved config behaves like an unconfigured buffer rather than like something arbitrary.

impl Eq for IndentUnit

impl PartialEq for IndentUnit

fn eq(&self, other: &IndentUnit) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for IndentUnit