I wonder why round-trip is such a small concern for people implementing serializers/deserializers of various kinds.
I usually throw in an "Unknown" node type, which stores things unaltered until I can understand things again. The parsers I usually write are very small, so I haven't seen what issues comes up at scale, maybe there are dragons lurking .
Yes, and there are probably a lot of other clever ideas. But the better solution is probably just to implement more of the spec. Once you get through maybe 80% of the tags, you've eliminated 99.9% of the memory issue given their frequency distribution.
The original Word format was a literal dump of a part of the data segment of the Word process. Basically like an mmapped file. Super fast. It is a pity that modern languages and their runtimes do not allow data structures to be saved like that.
You can absolutely save data like that, it's just that it's a terrible idea. There are obvious portability concerns issues: little-endian vs. big endian, 32-bit vs. 64-bit, struct padding, etc.
Essentially, this system works great if you know the exact hardware and compiler toolchain, and you never expect to upgrade it with things that might break memory layout. Obviously this does not hold for Word: it was written originally in a 32-bit world and now we live in a 64-bit one, MSVC has been upgraded many times, etc. There's also address space concern: if you embed your pointers, are you SURE that you're always going to be able to load them in the same place in the address space?
The overhead of deserialization is very small with a properly written file format, it's nowhere near worth the sacrifice in portability. This is not why Word is slow.
Your mileage may be different. I didn't work on Word (though I talked to those guys about their format) but I worked on two other apps that used the same strategy in the same era. One, on load you had to fix up runtime data that landed in that part of the data segment. Two, the in memory representation was actually somewhat sparse. This meant that a serializer actually read and wrote less to disk than mapping the file. So documents were smaller and there was actually less i/o and faster loads.
The reason I hated it though was because it was very hard to version. I know the Word team had that problem, especially when the mandate came down for older versions to be able to read newer versions. Hard enough to organize the disk format so old versions can ignore stuff, but now you're putting the same requirements on the in-memory representation. Maybe Word did it better.
There's all kinds of discussions of recovering text from corrupted files that just kind of went away when they moved over to the explicit serialization in docx.
I see the author is here — I wonder if you also handle PDFs? Quick look at the site indicates that yes, but could you tell more about it? Do you also have a custom parser/serializer? Do you allow for PDF editing?
The reason for asking, is that I've had a shower thought of building custom PDF/doc reader for myself, that would allow me to easily take notes and integrate with Anki. Been doing that in Obsidian with the pdf plugin, but it's too slow. At the same time, I've heard that PDF spec is not easy to work with, so I'm curious about your experience on that front.
There's actually an example PDF in the bundle if you click "Fetch Example" from the web preview at: https://tritium.legal/preview.
Under the hood, Tritium is using PDFium[1]. That's the same library used by Chrome, for example. The PDF spec is another animal that will be tackled in due course, but most legal users only need to view and comment on PDFs.
Try and find a binding to PDFium from your language of choice and start at that layer. PDFs are complex beasts, most of which complexity it may not be necessary to try to tackle in the first instance.
Thanks for the kind words, and I have given it serious thought.
It's definitely not impossible in the future.
I just don't think there is enough interest right now in contributing to the underlying tech without generalizing it so much that it basically becomes an inferior LibreOffice.
Instead, the business model for Tritium is to give away the niche legal product for free to the community, but charge commercial users who need more granular control over its network activity, etc. This gives smaller start-ups, law offices and in-house shops a chance to benefit from the niche features while reserving for more demanding organizations to express an interest in and benefit from advanced features.
I think you should just charge everyone. I can't imagine there are many people in the community who would have a use for it but aren't professionals who could pay money for it.
You could make a special exemption for non-profits and public defenders.
Giving it away for free just creates potential for freeloaders.
Great product idea by the way! Hard to believe lawyers have gone without this for so long.
I thought about that as well, but it's really just so core to every aspect of the product that Tritium needs to own it 100%. We just don't have the capacity to take a tradeoff that is favorable to the broader use case. I highlighted this issue in particular but there were other places where Tritium's needs diverged from the docx_rs approach. (e.g., dealing with references)
[NOTE: one dragon would be the memory consumption alluded to in the article.]
Essentially, this system works great if you know the exact hardware and compiler toolchain, and you never expect to upgrade it with things that might break memory layout. Obviously this does not hold for Word: it was written originally in a 32-bit world and now we live in a 64-bit one, MSVC has been upgraded many times, etc. There's also address space concern: if you embed your pointers, are you SURE that you're always going to be able to load them in the same place in the address space?
The overhead of deserialization is very small with a properly written file format, it's nowhere near worth the sacrifice in portability. This is not why Word is slow.
The reason I hated it though was because it was very hard to version. I know the Word team had that problem, especially when the mandate came down for older versions to be able to read newer versions. Hard enough to organize the disk format so old versions can ignore stuff, but now you're putting the same requirements on the in-memory representation. Maybe Word did it better.
The reason for asking, is that I've had a shower thought of building custom PDF/doc reader for myself, that would allow me to easily take notes and integrate with Anki. Been doing that in Obsidian with the pdf plugin, but it's too slow. At the same time, I've heard that PDF spec is not easy to work with, so I'm curious about your experience on that front.
There's actually an example PDF in the bundle if you click "Fetch Example" from the web preview at: https://tritium.legal/preview.
Under the hood, Tritium is using PDFium[1]. That's the same library used by Chrome, for example. The PDF spec is another animal that will be tackled in due course, but most legal users only need to view and comment on PDFs.
Try and find a binding to PDFium from your language of choice and start at that layer. PDFs are complex beasts, most of which complexity it may not be necessary to try to tackle in the first instance.
[1] https://pdfium.googlesource.com/pdfium/
It's definitely not impossible in the future.
I just don't think there is enough interest right now in contributing to the underlying tech without generalizing it so much that it basically becomes an inferior LibreOffice.
Instead, the business model for Tritium is to give away the niche legal product for free to the community, but charge commercial users who need more granular control over its network activity, etc. This gives smaller start-ups, law offices and in-house shops a chance to benefit from the niche features while reserving for more demanding organizations to express an interest in and benefit from advanced features.
You could make a special exemption for non-profits and public defenders.
Giving it away for free just creates potential for freeloaders.
Great product idea by the way! Hard to believe lawyers have gone without this for so long.