Method parse_set_class_item

regex/regex-syntax/src/ast/parse.rs:1851–1863

Parse a single item in a character class as a primitive, where the primitive either consists of a verbatim literal or a single escape sequence. This assumes the parser is positioned at the beginning of a primitive, and advances the parser to the first position after the primitive if successful. Note that it is the caller's responsibility to report an error if an illegal primitive was parsed.

(&self)

    /// Note that it is the caller's responsibility to report an error if an
    /// illegal primitive was parsed.
    fn parse_set_class_item(&self) -> Result<Primitive> {
        if self.char() == '\\' {
            self.parse_escape()
        } else {
            let x = Primitive::Literal(ast::Literal {
                span: self.span_char(),
                kind: ast::LiteralKind::Verbatim,
                c: self.char(),
            });
            self.bump();
            Ok(x)
        }
    }

    /// Parses the opening of a character class set. This includes the opening
    /// bracket along with `^` if present to indicate negation. This also