Dear lazyweb,
I would really really love a JavaScript mode for emacs which indented “for each” correctly:
for each(let o in a) {
// single indent
process(o);
}
I’d love it enough to buy a 6-pack for the person who made it happen.
I think we must all have OCD. It’s interesting (to me at least) which things I launch from the GUI (firefox, emacs). Is there a way to get the “most-clicked launchers” in gnome?
tchaikovsky.smedbergs.us:~
bsmedberg $ uname -a
Linux tchaikovsky.smedbergs.us 2.6.23.15-137.fc8 #1 SMP Sun Feb 10 17:03:13 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
tchaikovsky.smedbergs.us:~
bsmedberg $ history | awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head
271 hg
148 make
122 cd
44 less
43 rm
35 dir
33 exit
27 cvs
25 svn
18 /builds/gcc-dehydra/installed/bin/gcc
One of the things that makes mercurial useful and frustrating at the same time is that history is not linear. History can separate and join at multiple places. Tools such as hg log can’t show the outline of history clearly. There have been several attempts to remedy this situation: hg glog prints a revision graph using ASCII art, and hg view allows browing a repository history in a GUI app written in TK.
I think we can do better, so I started a new project: it is an extension to hgweb which allows browsing repository history graphically in a web browser. You can navigate graphically through revisions, and it will load new revisions on demand. Note that I’ve only tested it with Firefox, and it won’t work in IE (no SVG support):
mozilla-central on office.smedbergs.us.
There is certainly lots more that can and should be done:
Unfortunately I don’t have any more time to spend on this project. So I’m looking for volunteers to come forward and finish it.
The code is here. It is packaged as a single mercurial extension which must be installed in a global hgrc file, and a www/ directory with static files. I believe this extension will work correctly against Mercurial 1.0: I’ve been testing it against a mercurial-crew pull from a couple days ago.
The hgweb extension exists primarily to provide repository information in JSON format. I hope that it will be useful for other kinds of projects as well.
Christians, to the Pascal Victim
Offer your thankful praises!
A Lamb the sheep redeems;
Christ, who only is sinless,
Reconciles sinner to the Fater.
Death and life have contended
in that combat stupendous:
The Prince of life, who died,
reigns immortal,
Speak, Mary, declaring
What you saw, wayfaring.
“The tomb of Christ, who is living,
The glory of Jesus’ resurrection;
Bright angels, attesting
The shroud and napkin resting.
Yes, Christ my hope is arisen;
To Galilee he goes before you.
Christ indeed from death is risen,
our new life obtaining.
Have mercy, victor King,
eve reigning!
Amen. Alleluia!
The sequence for Easter Sunday, “Victimae pachali laudes”
Mozilla got me a new computer recently: one that can build Mozilla clobber in 7 minutes, or do a full XPCOMGC rewriting pass in 90 minutes. I wanted to be able to run Windows in a VM on this machine, but I’ve had a really unpleasant time setting up virtualization. This is a tale of what I’ve tried:
I’m still frustrated. I now have a Windows Vista license that is legal on this machine, but I haven’t installed it yet: I really want a bridged network, and preferably one that comes up automatically every time the host machine starts. I don’t really know much about Linux networking, or even what “a network” means in Linux… I just want a simple option like I used to have in VMWare: “Use bridged network” and it all works… but with better performance because KVM and Xen can both use fully virtualized I/O and multiple CPUs.
Does anyone know of a good guide to getting this working in a permanent sort of way?
No.
GCC Dehydra allows us to do analysis passes on our existing code. In the far future it may also allow us to do optimization passes. But it does not have the ability to do code rewriting, and probably won’t gain that ability any time soon. In order to be able to do C++->C++ transformations, you have to have correct end positions for all statements/tokens, not just beginning positions. GCC does not track this information, and making it do so would be a massive undertaking.
Mozilla2 still lives in a dual world where automatic code refactoring is done using the elsa/oink toolchain, while static analysis is taking place using the GCC toolchain.
I wrote my first mercurial extension today. It will print a log of all the commits you need to get from a changeset A which used to be the only head of a repository to a changeset B which is now the only head of the repository.It’s part of a project to get our buildbots hooked up to mercurial in a sane way. I need to make the same logic available via HTTP. It wasn’t too hard, but there are some tricky/undocumented things in the mercurial API that made life difficult.
between command in the wire protocol doesn’t do what you think it does, or what the documentation seems to say it does. Instead of returning all the changesets between point A and point B, it walks backward through the list returning a selection of changesets along the line. The farther you go back the less often it will pick a changeset to return.
cmdutil.show_changeset can be used to show changesets the same way hg log does. I haven’t yet figured out how to expose all of the formatting options it accepts as options accepted by my extension.
In the header file that declares class nsAutoString, there is an important comment: “Do not allocate this class on the heap”. This rule, buried deep in a header file that almost nobody reads, is a small example of a problem that plagues the Mozilla codebase: it’s easy to write incorrect code.
Mozilla, and XPCOM in particular, uses a meta-language on top of C++. This meta-language of helper classes and typesafe templates allows experienced XPCOM coders to avoid some of the complexities of XPCOM refcounting and memory management. Unfortunately, it is possible, even easy, to use this meta-language incorrectly or inefficiently. The following code, while correct C++, is incorrect “Mozilla C++”:
class Foo
{
private:
nsAutoString mStr;
...
};
void Bad()
{
Foo *foo = new Foo(); // allocated nsAutoString on the heap!
}
Errors such as this are especially insidious because the code works correctly; it is merely an inefficient use of memory which can add up quickly.
Taras and David have been working on a solution which will allow application-specific rules such as “only allocate nsAutoString on the stack” to be enforced at compile-time. It is called Dehydra GCC. It is a tool which translates the internal GCC representation of C++ code into a JavaScript object model, and allows application authors to write analysis passes as scripts.
This past week I hooked up Dehydra to the Mozilla build system. It is now possible to configure --with-static-checking=/path/to/gcc_dehydra.so and Dehydra will enforce a few basic rules: classes annotated with NS_STACK_CLASS may only be allocated on the stack, and classes annotated with NS_FINAL_CLASS may not be subclassed. For an example of a more complicated analysis, see bug 420933, ensuring that XPCOM methods handle outparams correctly.
Dehydra currently only works on Linux, and building it is a bit complicated: a custom patched GCC is required, as well as a spidermonkey package. Complete directions are available on the Mozilla Developer Center.
Dehydra is still a work in progress. We are working to complete the following tasks:
We are actively looking for hackers to help out with this project. There are many different kinds of tasks people can help with:
I am very excited about the prospect of using static checking tools such as this one to improve our code quality and development cycle, and I’m looking forward to new and unexpected uses for this code! In future posts I will cover basics of writing a dehydra script.
I have a common problem with revision control:
GC.cpp
GC.cpp
Dear lazyweb, is there a tool I can use to interactively separate out these changes into two changesets? The solution should work with my mercurial workflow, no “use git-rebase” comments please. I happen to be using patch queues, but a solution that worked on real mercurial changesets or on raw patches would also be acceptable. It happens that usually the patch hunks for problem X and problem Y are completely separate, so a simple tool that let me throw “this hunk for X, this hunk for Y” would probably be ok. Better would be something like a three-way merge tool where I can edit an intermediate state between a fixed start-point and end-point.
In my spare time I’m working on long-needed program for engraving Gregorian chant. (“Engraving” is to music what “typesetting” is for text.) Below are the requirements I’ve been designing around:
My current plan is to write the app in JS, provide output in SVG, and deploy over the web. I have a mockup/prototype of the SVG I’d like to produce:
There is one major hurdle I haven’t figured out yet: I don’t know how to position the text. The positioning of Gregorian chant is very precise: the first neume (note) of each syllable is placed over the center of the vowel of the syllable. In addition, the spacing of neumes is arranged so that there are precise amounts of whitespace between each element and syllable, and hyphens between syllables are lengthened or shortened as necessary to fit. What is the best way to give a web application precise text measurement of individual letters within a syllable (including any kerning and ligatures)?
Ideally I’d like a way to do this with the user’s own fonts, but if I need to preprocess a font file to get metrics out of it, I guess that’s ok too.
Dear lazyweb, can somebody verify that Adobe InDesign/Quark/your favorite DTP program imports my sample SVG file correctly and usably? I don’t have a copy at the moment, and it’s rather expensive just for an import test…
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