They can oneshot relatively simple parsers/encoders/decoders with a proper spec, but it’s a completely different ballgame when you’re trying to parse a very domain knowledge heavy file format (like the format electronics CAD) with decades of backwards compatible cruft spread among hundreds of megabytes of decompiled Delphi and C# dlls (millions of lines).
The low level parts (OLE container, streams and blocks) are easy but the domain specific stuff like deserializing to typed structs is much harder.
The low level parts (OLE container, streams and blocks) are easy but the domain specific stuff like deserializing to typed structs is much harder.