Struct fluent_syntax::parser::ParserError

pub struct ParserError {
    pub pos: Range<usize>,
    pub slice: Option<Range<usize>>,
    pub kind: ErrorKind,
}

Error containing information about an error encountered by the Fluent Parser.

Errors in Fluent Parser are non-fatal, and the syntax has been designed to allow for strong recovery.

In result ParserError is designed to point at the slice of the input that is most likely to be a complete fragment from after the end of a valid entry, to the start of the next valid entry, with the invalid syntax in the middle.

Example

use fluent_syntax::parser;
use fluent_syntax::ast;

let ftl = r#"
key1 = Value 1

g@Rb@ge = #2y ds

key2 = Value 2

"#;

let (resource, errors) = parser::parse_runtime(ftl)
    .expect_err("Resource should contain errors.");

assert_eq!(
    errors,
    vec![
        parser::ParserError {
            pos: 18..19,
            slice: Some(17..35),
            kind: parser::ErrorKind::ExpectedToken('=')
        }
    ]
);

assert_eq!(
    resource.body[0],
    ast::Entry::Message(
        ast::Message {
            id: ast::Identifier {
                name: "key1"
            },
            value: Some(ast::Pattern {
                elements: vec![
                    ast::PatternElement::TextElement {
                        value: "Value 1"
                    },
                ]
            }),
            attributes: vec![],
            comment: None,
        }
    ),
);

assert_eq!(
    resource.body[1],
    ast::Entry::Junk {
        content: "g@Rb@ge = #2y ds\n\n"
    }
);

assert_eq!(
    resource.body[2],
    ast::Entry::Message(
        ast::Message {
            id: ast::Identifier {
                name: "key2"
            },
            value: Some(ast::Pattern {
                elements: vec![
                    ast::PatternElement::TextElement {
                        value: "Value 2"
                    },
                ]
            }),
            attributes: vec![],
            comment: None,
        }
    ),
);

The information contained in the ParserError should allow the tooling to display rich contextual annotations of the error slice, using crates such as annotate-snippers.

Fields

pos: Range<usize>

Precise location of where the parser encountered the error.

slice: Option<Range<usize>>

Slice of the input from the end of the last valid entry to the beginning of the next valid entry with the invalid syntax in the middle.

kind: ErrorKind

The type of the error that the parser encountered.

Trait Implementations

impl Clone for ParserError

fn clone(&self) -> ParserError

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for ParserError

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

Formats the value using the given formatter.

impl Display for ParserError

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

Formats the value using the given formatter.

impl Error for ParserError

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

The lower-level source of this error, if any.

fn backtrace(&self) -> Option<&Backtrace>

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

Returns a stack backtrace, if available, of where this error occurred.

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

impl PartialEq<ParserError> for ParserError

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl StructuralPartialEq for ParserError