Enum FormatError 

#[non_exhaustive]
pub enum FormatError {
    OutOfBounds {
        start: u32,
        end: u32,
        len: usize,
    },
    NotCharBoundary {
        offset: u32,
    },
    NotContiguous {
        expected: u32,
        found: u32,
    },
}

Why format() could not format a tree.

The formatter accepts any tree shape, error nodes included; it refuses only a tree whose tokens do not describe source, because formatting such a tree would lose or invent text.

Examples

use fmt_lang::syntax_lang::{Element, Node, Span, Token, TokenKind};
use fmt_lang::{format, FormatError, Style};

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
struct Word;
impl TokenKind for Word {}

// A token reaching past the end of the source.
let tree = Node::new(Word, vec![Element::Token(Token::new(Word, Span::new(0, 9)))]);
let err = format(&tree, "short", &Style::default(), 80).unwrap_err();
assert_eq!(err, FormatError::OutOfBounds { start: 0, end: 9, len: 5 });

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

OutOfBounds

A token’s span reaches past the end of the source. The tree was built from different text; parse source again.

Fields

start: u32

Start of the token’s span.

end: u32

End of the token’s span.

len: usize

Length of the source in bytes.

NotCharBoundary

A token boundary falls inside a multi-byte character. The tree was built from different text; parse source again.

Fields

offset: u32

The offending byte offset.

NotContiguous

Consecutive tokens leave a gap or overlap, so the tree is not lossless: text between them would be lost or written twice. Every byte of the tree’s range must belong to exactly one token (trivia included).

Fields

expected: u32

Where the next token should have started (the previous token’s end).

found: u32

Where it actually started.

Trait Implementations

impl Clone for FormatError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FormatError

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

Formats the value using the given formatter.

impl Display for FormatError

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

Formats the value using the given formatter.

impl Eq for FormatError

impl Error for FormatError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for FormatError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for FormatError