thurston

8 ms·

1.
by thurston 7y ago
Sorry I didn't see the parent you were responding too, so my point is actually the same as you already made. Thanks.
2.
by thurston 7y ago
Ragel has the advantage that CPU blowups happen at compile time, rather than run-time. Other risks aside, they would have avoided this problem had they been using ragel or something similar to pre-compile their patterns into deterministic m
3.
by thurston 8y ago
What rarely gets discussed in this case was that old, working code was modified in a critical way in order to accommodate new code when that didn't need to be done at all. It was actually a failure in the software development process.
4.
by thurston 8y ago
Initial list: C, C++, Objective-C, Objective-C++, ASM, Crack, C#, D, Go, Java, JavaScript, Julia, OCaml, Ruby, Rust Others can be added.
5.
Additional Target Languages Return to Ragel 7(colm.net)
2 points by thurston 8y ago|1 comments
6.
Changes to Ragel in Response to the CloudFlare Incident(colm.net)
4 points by thurston 10y ago|0 comments
7.
by thurston 10y ago
Well doing that would mean ragel would incorrectly read one character, rather than run off forever. Personally I'd rather have the latter. Much easier to catch with memory checkers. Eventually you try to read some thing you're not
8.
by thurston 10y ago
Author of Ragel here. An experienced Ragel programmer would know that when you start setting the EOF pointer you are enabling code paths that never executed before. Like, potentially buggy ones. Eek!
9.
by thurston 11y ago
Thanks!
10.
by thurston 11y ago
WRT Lua, not at this time, but it is one I would like to support. Won't be too much work to add it.
11.
by thurston 11y ago
Keep using them is how you overcome this ;)
12.
by thurston 11y ago
At their core they target different language classes. Ragel deals with regular, whereas LPeg deals with context-free grammars.
13.
by thurston 11y ago
My pleasure, thank you for the note!
14.
by thurston 11y ago
Not at this time. But yes Ragel 7 will make it much easier. The first round of new languages I added helped me polish the technique. Once 7 is out and vetted it will make sense to add more.
15.
by thurston 11y ago
Same reason you would want to use yacc to write a parser. A grammar annotated with code is a nice way to express a parser. If the language happens to be regular, you can use ragel to generate a directly executable deterministic state machin
16.
by thurston 11y ago
Ragel allows embedding actions into the subexpressions of a regular expression. This allows one to compose a parser using a single regular expression.
17.
by thurston 15y ago
help me! http://www.complang.org/dsnp/
18.
by thurston 15y ago
Just plain old text as it came in. I see now that is not what you were referring to. You're talking about JSON, XML, etc I now think. There is also a print_xml function, which puts the tree into XML, but it's mostly used for debugging at th
19.
by thurston 15y ago
They are related systems. DMS is much more mature.
20.
by thurston 15y ago
Ya it's currently hard to find. http://d-cent.org/fsw2011/ I need help from people like you actually. What I've done. 1. defined the protocol 2. implmented it in a C++ daemon that a) talks to other daemons b) serves the content m
21.
by thurston 15y ago
Indeed I did not follow what you meant. I missed the "persistent" and saw ... "don't incur the cost of copying." I took that to mean that you were referring to not maintaining any history and using a single, mutable global state. It is with
22.
by thurston 15y ago
Yes I understand these techniques, in fact they are heavily in use in Colm, just not for maintaining the global state that is used for the parsing feedback loop. I use the term "copy" in the general sense to make discussion easier. Conceptu
23.
by thurston 15y ago
:) If I had my way this comment would be closer to the top. Not many grammar-based parsing systems can claim raw DNS parsing.
24.
by thurston 15y ago
Colm has built-in serialization. There is still some work to do in this area though. Colm will preserve whitespace for minimal disruption of untransformed text, but figuring out what to do at the boundaries between modified and unmodified t
25.
by thurston 15y ago
To have both generalized parsing and context dependent parsing you need to somehow revert changes to the global state when you backtrack. You can do this by restoring it to old versions, which requires copying the state and keeping the hist
26.
by thurston 15y ago
Then you forgo generalized parsing. Edit: indeed I did not follow what you meant.
27.
by thurston 15y ago
There are some difficult problems in that space. I've posted to HN and reddit a few times, but mostly I've been working on it quietly so I can focus. Lately, that's starting to change. I'll be talking about it at FSW 11 in Berlin in a few w
28.
by thurston 15y ago
Where is the grammar-dependent scanning? Note that threading the context through the parse tree while maintaining fully generalized parsing requires keeping all versions of the parsing context in memory. Consider making a C++ parser in that
29.
by thurston 15y ago
If they are then I don't deserve to be called "Dr. Thurston!"
30.
by thurston 15y ago
Grammar: http://svn.complang.org/colm/trunk/colm/lmparse.kl

More ›