Method parse_part

crates/common/src/format.rs:1096–1132

(
        chars: &mut impl PeekingNext<Item = CodePoint>,
    )

impl FieldNamePart {
    fn parse_part(
        chars: &mut impl PeekingNext<Item = CodePoint>,
    ) -> Result<Option<Self>, FormatParseError> {
        chars
            .next()
            .map(|ch| match ch.to_char_lossy() {
                '.' => {
                    let mut attribute = Wtf8Buf::new();
                    for ch in chars.peeking_take_while(|ch| *ch != '.' && *ch != '[') {
                        attribute.push(ch);
                    }
                    if attribute.is_empty() {
                        Err(FormatParseError::EmptyAttribute)
                    } else {
                        Ok(Self::Attribute(attribute))
                    }
                }
                '[' => {
                    let mut index = Wtf8Buf::new();
                    for ch in chars {
                        if ch == ']' {
                            return if index.is_empty() {
                                Err(FormatParseError::EmptyAttribute)
                            } else if let Some(index) = parse_usize(&index) {
                                Ok(Self::Index(index))
                            } else {
                                Ok(Self::StringIndex(index))
                            };
                        }
                        index.push(ch);
                    }
                    Err(FormatParseError::MissingRightBracket)
                }
                _ => Err(FormatParseError::InvalidCharacterAfterRightBracket),
            })
            .transpose()
    }
}

#[derive(Debug, PartialEq)]