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|
use std::ops::Range;
use thiserror::Error;
/// 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`.
#[derive(Error, Debug, PartialEq, Clone)]
#[error("{}", self.kind)]
pub struct ParserError {
/// Precise location of where the parser encountered the error.
pub pos: 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.
pub slice: Option<Range<usize>>,
/// The type of the error that the parser encountered.
pub kind: ErrorKind,
}
macro_rules! error {
($kind:expr, $start:expr) => {{
Err(ParserError {
pos: $start..$start + 1,
slice: None,
kind: $kind,
})
}};
($kind:expr, $start:expr, $end:expr) => {{
Err(ParserError {
pos: $start..$end,
slice: None,
kind: $kind,
})
}};
}
/// Kind of an error associated with the [`ParserError`].
#[derive(Error, Debug, PartialEq, Clone)]
pub enum ErrorKind {
#[error("Expected a token starting with \"{0}\"")]
ExpectedToken(char),
#[error("Expected one of \"{range}\"")]
ExpectedCharRange { range: String },
#[error("Expected a message field for \"{entry_id}\"")]
ExpectedMessageField { entry_id: String },
#[error("Expected a term field for \"{entry_id}\"")]
ExpectedTermField { entry_id: String },
#[error("Callee is not allowed here")]
ForbiddenCallee,
#[error("The select expression must have a default variant")]
MissingDefaultVariant,
#[error("Expected a value")]
MissingValue,
#[error("A select expression can only have one default variant")]
MultipleDefaultVariants,
#[error("Message references can't be used as a selector")]
MessageReferenceAsSelector,
#[error("Term references can't be used as a selector")]
TermReferenceAsSelector,
#[error("Message attributes can't be used as a selector")]
MessageAttributeAsSelector,
#[error("Term attributes can't be used as a selector")]
TermAttributeAsPlaceable,
#[error("Unterminated string literal")]
UnterminatedStringLiteral,
#[error("Positional arguments must come before named arguments")]
PositionalArgumentFollowsNamed,
#[error("The \"{0}\" argument appears twice")]
DuplicatedNamedArgument(String),
#[error("Unknown escape sequence")]
UnknownEscapeSequence(String),
#[error("Invalid unicode escape sequence, \"{0}\"")]
InvalidUnicodeEscapeSequence(String),
#[error("Unbalanced closing brace")]
UnbalancedClosingBrace,
#[error("Expected an inline expression")]
ExpectedInlineExpression,
#[error("Expected a simple expression as selector")]
ExpectedSimpleExpressionAsSelector,
#[error("Expected a string or number literal")]
ExpectedLiteral,
}
|
