Enum wast::lexer::LexError

#[non_exhaustive]
pub enum LexError {
    DanglingBlockComment,
    Unexpected(char),
    InvalidStringElement(char),
    InvalidStringEscape(char),
    InvalidHexDigit(char),
    InvalidDigit(char),
    Expected {
        wanted: char,
        found: char,
    },
    UnexpectedEof,
    NumberTooBig,
    InvalidUnicodeValue(u32),
    LoneUnderscore,
    ConfusingUnicode(char),
}

Errors that can be generated while lexing.

All lexing errors have line/colum/position information as well as a LexError indicating what kind of error happened while lexing.

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.

DanglingBlockComment

A dangling block comment was found with an unbalanced (; which was never terminated in the file.

Unexpected(char)

An unexpected character was encountered when generally parsing and looking for something else.

InvalidStringElement(char)

An invalid char in a string literal was found.

InvalidStringEscape(char)

An invalid string escape letter was found (the thing after the \ in string literals)

InvalidHexDigit(char)

An invalid hexadecimal digit was found.

InvalidDigit(char)

An invalid base-10 digit was found.

Expected

Fields

wanted: char

The character that was expected to be found

found: char

The character that was actually found

Parsing expected wanted but ended up finding found instead where the two characters aren’t the same.

UnexpectedEof

We needed to parse more but EOF (or end of the string) was encountered.

NumberTooBig

A number failed to parse because it was too big to fit within the target type.

InvalidUnicodeValue(u32)

An invalid unicode value was found in a \u{...} escape in a string, only valid unicode scalars can be escaped that way.

LoneUnderscore

A lone underscore was found when parsing a number, since underscores should always be preceded and succeeded with a digit of some form.

ConfusingUnicode(char)

A “confusing” unicode character is present in a comment or a string literal, such as a character that changes the direction text is typically displayed in editors. This could cause the human-read version to behave differently than the compiler-visible version, so these are simply rejected for now.

Trait Implementations

impl Clone for LexError

fn clone(&self) -> LexError

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for LexError

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

Formats the value using the given formatter.

impl Display for LexError

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

Formats the value using the given formatter.

impl PartialEq<LexError> for LexError

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

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

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

This method tests for !=.

impl Eq for LexError

impl StructuralEq for LexError

impl StructuralPartialEq for LexError