Working with locations

The Location structure includes full first-last locations:

• The compilation unit
• The first and last lines
• The first and last columns
• The first and last offsets

Logically, the Location structure stores solely the compilation unit reference and the first and last offsets. Then, it computes lines and columns through that compilation unit and these two offsets.

Offset

An offset is a zero-based UTF-8 byte position in a source text, as the str type in the Rust langauge is UTF-8 encoded.

Byte ranges

If a source text is situated in a place such as inside a MXML file, you may want to avoid creating a new compilation unit to parse that source text while maintaining line numbers and columns.

It is simple to do that: just specify the byte_range option, passing the first and last byte offsets of an existing compilation unit:

ParserFacade(ParserOptions {
    byte_range: Some((first_offset, last_offset)),
    ..default()
})

You may then invoke parser methods within that ParserFacade object.

Determining offsets

The parser attaches full source location information, including within MXML nodes, crucial for the byte_range option.

For example:

• MXML attribute values contain Location data (attribute.value.1) including the quotes.
• MXML CDATA contain Location data (MxmlContent::CData((_, location))) including the <![CDATA[ and ]]> delimiters.