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Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

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Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#221

Post by ternaryoperator »

eponeponepon wrote: post #50
oneeyedpigeon wrote: post #4

I don't quite get Linus' problem with XML for document markup (for anything else - config files, build scripts - sure, XML is horrible). Does anyone know any more details about what his specific gripe is? For me, asciidoc (which looks very similar, conceptually, to markdown) suffers from one huge problem: it's incomplete. Substituting symbols for words results in a more limited vocabulary, if that vocabulary is to re…

Document markup is the one place XML is a no-brainer - more specifically, long-form, highly structured documents (i.e., essentially books). Without it, publishing would be stuck in a morass of nebulous, ill-documented proprietary messes, and a great deal of current learning would be at risk of being lost to posterity. The fact that there are associated open standards such as XSLT with which to transform it is just th…

>Document markup is the one place XML is a no-brainer

That's only true for minimally formatted documents. For anything that approaches professional typesetting requirements, XML is a nightmare.

By far the biggest problem, it the requirement that inner elements must be closed before outer ones can be. This frequently means that the software must do a huge amount of read-ahead to figure out which aspect of the formatting changes first to make that formatting element innermost.

Sometimes, that's simply not possible to arrange and so you have to close a whole bunch of elements and then reopen all but one of them.

All this because a constraint of the format.

Ideal formats, such as used by typesetting systems that don't use XML, allow you to say: keep this formatting trait on until it's switched off. There is no concept of every element needing to be a subset of its encompassing element.

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#222

Post by rcxdude »

lmm wrote: post #24
bhaak wrote: post #15

What's with all the XML hate? Of course, doing everything in XML is a stupid idea (e.g. XSLT and Ant) and thanks heaven that hype is over. But if I want something that is able to express data structures customized by myself, usually with hierarchical data that can be verified for validity and syntax (XML Schemas or old-school DTD), what other options are there? Doing hierarchical data in SQL is a bitch and if you wan…

If used sensibly XML isn't too bad. But there's a whole lot of cruft in the standard that seems to do nothing except make it harder to use. Part of this is a problem with popular libraries rather than inherent to the format, but we judge a thing by its ecosystem rather than in isolation. So: namespaces are a pain, making it much harder than it should be to just make my xpath work. DTDs are annoying, especially when a…

Indeed. XML gets a lot of hate because it's so difficult to use. It would be fine if you could use it without having to care about the 100 features you don't care about and just use the ones you need, but pretty much every library I've seen makes parsing (or generating) a document a huge and complicated task, and most of it is completely irrelevant to the problem I'm trying to solve.

And because of this almost no-one bothers to actually handle it properly so you often can't actually use the advanced features even if you wanted to.

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#223

Post by sanderjd »

jdbernard wrote: post #201
sanderjd wrote: post #144

Earlier quoted context omitted.

How does the [deserializer] step in the XML example know to call into [bignum], and why can't the [json reader] in the JSON example have that knowledge in the same fashion?

Because the XML document has a semantic meaning that is specifically designed for this application. It may even have a schema definition document which formally defines what types to expect. JSON, by contrast, has type definitions imposed on it by its nature as JavaScript code.

I've sort of lost track of what this debate is about... Assuming you don't have a schema definition, it seems to me that you can just as easily parse `{ "salary": "1e999" }` with application-encoded semantics as `1e999` with (again) application-encoded semantics. Maybe having a formal schema definition is a win, though.

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#224

Post by icebraining »

tokenizerrr wrote: post #145
seanalltogether wrote: post #136

Earlier quoted context omitted.

My biggest hatred of xml as a data structure, and believe me I've seen this in production systems more then once, is that it allows for the following. Personal ... Business ... 496F3AB This may seem innocuous, but XML allows mixing of arrays and objects too liberally, and makes automatic parsing overly complex. At first appears to be an array of account objects, but wait now that we reach the end we find that is an o…

Well yes. The problem there is that someone made a bad decision on how to structure their XML. If the same was done like this: Personal ... Business ... it would make a lot more sense, I think.

Or:

      
        496F3AB
        
           
    	     Personal
             ...
    	   
    	   
    	     Business
    	     ...

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#225

Post by icebraining »

aashishkoirala wrote: post #37

This is what Linus does. He has strong opinions and he throws them around. You can't let that get to you. Both XML and JSON are just fine if used properly.

http://harmful.cat-v.org/software/xml/

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#226

Post by pcj »

>>So I've been thinking about this for basically months, but the way I work, I actually want to have a good mental picture of what I'm doing before I start prototyping. And while I had a high-level notion of what I wanted, I didn't have enough of a idea of the details to really start coding.

This might be a tangential discussion. Earlier, I used to have a similar approach. Can't code until I have the complete picture. But, it's tough to do in a commercial world and you have deliverables. So, nowadays, I start with what I know and scramble my way until I get a better picture. There are times when that approach works. But, there have been days where I was like - "wish I had spent some more time thinking about this".

I am curious how folks on HN handle this "coding block".

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#227

Post by andrewflnr »

haberman wrote: post #197
TelmoMenezes wrote: post #141

Earlier quoted context omitted.

This is a good point, but I feel that discouraging this type of approach is not the way to go. I apologise in advance for ranting... I hope this is not too off-topic, but instead a "zoom out" on the issue. This touches on something deep and wrong about how we use computers these days. Computers are really good at being computers, and the amplification of intellectual capabilities they afford is tremendous, but this i…

Lack of Turing-completeness can be a feature. Take PDF vs PostScript. The latter is Turing-complete and therefore you cannot jump to an arbitrary page or even know how many pages the document has without running the entire thing first. By limiting expressiveness you also gain static analysis and predictability. It's not about limiting the potential of computers, it's about designing systems that strike the right bala…

If you have a nice data format like s-exprs, it's a fairly simple matter to just aggressively reject any code/data that can't be proven harmless. For example, if you're loading saved game data, just verify that the table contains only tables with primitive data; if there's anything else, throw an error. Then you can safely execute it in a turing-complete environment and be sure it won't cause problems.

Speaking for myself, in my ideal world this sort of schema-checking and executing is ubiquitous and easy. Obviously that's not the world today. While there are tools for checking JSON schemata there doesn't seem to be a standard format. I wonder how hard it would be to implement a Lua schema-checker.

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#228

Post by rossjudson »

rcxdude wrote: post #222
lmm wrote: post #24

Earlier quoted context omitted.

If used sensibly XML isn't too bad. But there's a whole lot of cruft in the standard that seems to do nothing except make it harder to use. Part of this is a problem with popular libraries rather than inherent to the format, but we judge a thing by its ecosystem rather than in isolation. So: namespaces are a pain, making it much harder than it should be to just make my xpath work. DTDs are annoying, especially when a…

Indeed. XML gets a lot of hate because it's so difficult to use. It would be fine if you could use it without having to care about the 100 features you don't care about and just use the ones you need, but pretty much every library I've seen makes parsing (or generating) a document a huge and complicated task, and most of it is completely irrelevant to the problem I'm trying to solve. And because of this almost no-one…

This varies greatly from framework to framework, and language to language. On the JVM at least, the dark machinery that handles the XML is rather rigorously correct. Parsing and generation are trivial, especially using JAXP. You have multiple ways of working with XML (objects, DOM, push, pull).

XML is "good enough" for a lot of cases. There are lots of tools to mess around with it too, which is really quite valuable when you're experimenting with various kinds of data or you're debugging. Being able to extract out stuff you're interested in XML format means you can perform a lot of complex manipulations quite easily.

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#229

Post by phn »

dfc wrote: post #151
phn wrote: post #143

Earlier quoted context omitted.

Cheating is good, I remember having tons of fun with age of empires and sim city because I used cheat codes. If the player has fun, it's a nice feature! :D

And what about the people competing against the happy cheater?

Of course, in multi-player competitive games anti-cheating is a pretty big concern, because it works against the purpose of the game: a competition with well defined rules and conditions.

If the core of the game is single-player/non-competitive, why should we be so worried about cheating?

Re: Linus Torvalds: “I'm happily hacking on a new save format using ‘libgit2’”

#230

Post by phn »

ANTSANTS wrote: post #218
baq wrote: post #178

Earlier quoted context omitted.

in a single player game with save games on local disk? this question is nearly trolling.

Some people do compete for speed or score in single player games. Arcade games have always had scoreboards, modern "arcade-style" games have online ones, and a community can turn any solitary activity into a competitive one: http://speedrunslive.com/ http://speeddemosarchive.com/ Speedrunners are an exceptional case, but I think everyone gets a little annoyed when they look at a leaderboard and all the top players ha…

I DO get annoyed when I see those scores, but in a lot of cases even having a leaderboard is just something that was introduced in the game just to be more "social" and less because it makes sense in that specific game.

And yes, it's not ridiculous, on the contrary, it's perfectly understandable.

Of course, these kinds of questions depend a lot on the game in question, and I think they don't have a definitive answer :)

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