Struct flussab::text::LineReader

pub struct LineReader<'a> {
    pub reader: ByteReader<'a>,
    pub line: usize,
    pub line_start: usize,
}

Wraps a ByteReader to count track lines.

For performance reasons, counting lines isn’t done automatically. Instead, you are expected to read directly from the underlying ByteReader and to call line_at_offset whenever you advance past the end of a line.

If this is done, give_up can be used to generate SyntaxError’s that contain the source location and display the line containing the syntax error.

Fields

reader: ByteReader<'a>

The wrapped ByteReader.

line: usize

The current line, starting at 1.

line_start: usize

The position where the current line starts, as returned by ByteReader::position.

Implementations

impl<'a> LineReader<'a>

pub fn new(reader: ByteReader<'a>) -> Self

Creates a LineReader assuming line 1 starts at the current position of the passed ByteReader.

pub fn reader(&mut self) -> &mut ByteReader<'a>

Returns a mutable reference to the ByteReader.

While the reader field is directly accessible, using this method can be more convenient if a mutable reference is needed.

pub fn line_at_offset(&mut self, offset: usize)

Advance the line counter and record the start of a new line.

The offset value is relative to the current position() as returned by self.reader.

pub fn give_up<E>(&mut self, msg: impl Into<String>) -> E where
    E: From<Error> + From<SyntaxError>, 

Generate a syntax error at the current reader position.

pub fn give_up_at<E>(&mut self, position: usize, msg: impl Into<String>) -> E where
    E: From<Error> + From<SyntaxError>, 

Generate a syntax error at position.

This assumes that position is on the current line, otherwise the resulting LineColumn will be incorrect.