Struct LineShape 

pub struct LineShape {
    pub blank: bool,
    pub columns: u16,
    pub closer: bool,
    pub unindented: bool,
}

The only three facts the indent-guide builder needs about a line, in a Copy struct so it can be produced without materialising the line’s text.

Replaces three separate whole-line predicates (IndentUnit::is_blank, IndentUnit::columns_of, is_closer_line) that each took &str — which forced the caller to allocate a String per line. On the keystroke path that was one allocation per covered line per keystroke, and coverage is the whole document below WINDOW_CAP_LINES.

Fields

blank: bool

Every character is ’ ’, ‘\t’ or ‘\r’ — IndentUnit::is_blank.

columns: u16

Display columns of leading whitespace — IndentUnit::columns_of.

closer: bool

Non-blank and every non-whitespace character closes something — is_closer_line.

unindented: bool

Non-blank and starting hard against column 0. The scan_back_to_top_level test; equivalent to !blank && columns == 0, precomputed for clarity at the call site.

Implementations

impl LineShape

pub fn from_chars<I: Iterator<Item = char>>(chars: I, unit: &IndentUnit) -> Self

Stream chars (one line, trailing newline optional) into a shape. Allocation-free, and breaks early: once the line is known non-blank and known not-all-closers, no later character can change any field, which is the common case after one or two content characters.

Deliberately mirrors the three predicates byte-for-byte rather than approximating them:

• indent scanning stops at the first char that is not ’ ’ or ‘\t’, matching columns_of’s break;
• “blank” tests membership of {' ', '\t', '\r'} rather than Unicode whitespace, matching is_blank (so U+00A0 is content);
• closer-ness ignores whitespace and tests the same six characters is_closer_line does.

pub fn from_line(line: &str, unit: &IndentUnit) -> Self

Convenience for callers that already hold the text (tests, and any path where the line was materialised for another reason).

Trait Implementations

impl Clone for LineShape

fn clone(&self) -> LineShape

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for LineShape

impl Debug for LineShape

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

Formats the value using the given formatter.

impl Eq for LineShape

impl PartialEq for LineShape

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for LineShape