Hacker News: mcn

New comment by mcn in "Common Lisp in the 21st Century"

mcn — Tue, 11 Feb 2014 00:32:33 +0000

Another issue is old books. I recently got value out of PAIP and On Lisp, and I still see people recommend A Gentle Introduction to Symbolic Computation. Stepping beyond CL for a second, car and cdr have even deeper roots; for example if someone is introduced to the wider lisp-like world through SICP they will also have to become comfortable with car and cdr.

New comment by mcn in "Common Lisp in the 21st Century"

mcn — Mon, 10 Feb 2014 22:35:05 +0000

I think another factor is that while the primitives for modifying readtables made it into the standard, an interface for using them in a way that limits the changes to the code you own (and not, say, additional libraries you load) is something that the users had to come up with.

It's not a lot of code or too complex to do that, but it's not obvious either and some people got it wrong or do it differently and I think that made reader modifications less common than they otherwise might have been.

I haven't looked too closely at the details but some of cl21's changes look like they might try to address this issue.

New comment by mcn in "Lisp: It's Not About Macros, It's About Read"

mcn — Sun, 19 Feb 2012 16:04:13 +0000

I agree with you and lispm about the complexity of code walking in CL.

For your specific example of replacing calls to foo with another bit of code you may be able to get away with macrolet. (Example: http://letoverlambda.com/index.cl/guest/chap5.html#sec_4 )

New comment by mcn in "Advanced Data Structures MIT"

mcn — Thu, 09 Feb 2012 03:41:04 +0000

The MIT 2005 Introduction to Algorithms course is available.

http://ocw.mit.edu/courses/electrical-engineering-and-comput...

New comment by mcn in "Google adds verbatim search mode for your exact search terms"

mcn — Tue, 15 Nov 2011 19:41:44 +0000

> we’re also applying similar ideas directly to our algorithms, such as tuning the accuracy of when our query broadening search improvements trigger

As you are doing this, please keep in mind that when you incorrectly broaden my query, and there is no immediately obvious way to re-narrow it, it costs you much more than you gain each time you correctly broaden my query.

New comment by mcn in "Google scores most effective TV ad with Dear Sophie"

mcn — Wed, 09 Nov 2011 19:08:15 +0000

I found that one to be powerful, but double edged. It's unpleasant to remember that ad when researching a serious situation that is likely to have a negative outcome.

New comment by mcn in "Ask PG: Is there any chance of getting points displayed again"

mcn — Mon, 17 Oct 2011 21:51:34 +0000

>Past polls show that a substantial portion of readers (me included) think the points are very useful. They draw our attention to the best comments.

That is not the primary reason that I want points back. I believe that allowing people to signal their opinion with public upvotes discouraged redundant posts, and that visible upvotes encouraged participants to let their arguments stand rather than creating unnecessarily deep threads.

A secondary issue is that votes were a valuable part of the signal in many "Ask HN" threads.

New comment by mcn in "CL-ZMQ: Common Lisp ZeroMQ Binding"

mcn — Sun, 09 Oct 2011 21:58:16 +0000

Thanks for the quick response, and thanks for adding the note to the documentation.

(As to the quicklisp version being a bit stale, it looks like the last CFFI tagged release is 13 months old. I updated my above post to point to the official git repository.)

New comment by mcn in "CL-ZMQ: Common Lisp ZeroMQ Binding"

mcn — Sun, 09 Oct 2011 20:54:59 +0000

I'm looking forward to playing with this.

If you run into the following while installing:

"Unknown Grovel syntax: CFFI-GROVEL::BITFIELD"

You may need to download the git version of CFFI[1]. The 0.10.6 CFFI release doesn't have bitfield grovel support.

[1] http://common-lisp.net/gitweb?p=projects/cffi/cffi.git

I hit the above bug using what I believe was the latest quicklisp distributed version of CFFI.

Edit: Point to the official CFFI git instead of a fork and a patch.

New comment by mcn in "Web Surfing Helps at Work, Study Says"

mcn — Mon, 22 Aug 2011 14:57:04 +0000

Thank you for that; I recently tried to find out how he implemented his 30 second distraction-delay but I had misattributed the quote and so my search was unsuccessful. I think that the delay is a powerful idea.

The approach I'm experimenting with is a "productivity mode" toggle in a tiling windows manager which disables most of the windows manager commands, leaving me mostly stuck in whatever application(s) were already visible until I toggle it off. The toggle off function has a 30 second delay.

New comment by mcn in "Optimizely (YC W10) Increases Homepage Conversion Rate by 29%"

mcn — Thu, 09 Jun 2011 00:05:00 +0000

Keep in mind that the 1% margin of error applies to the measurements of the conversion rates. The 29% has a significantly higher margin of error.

New comment by mcn in "Ask HN : What do you think about my idea?"

mcn — Tue, 07 Jun 2011 01:30:33 +0000

There is a "dead" answer in this thread that you might be interested in too. (You can activate showdead in your profile.)

New comment by mcn in "Poll: Should HN display comment scores?"

mcn — Sun, 29 May 2011 05:11:33 +0000

I've noticed an increase in posts reiterating each other: it seems that the wrong kind of post is being used as a substitute good for the wrong kind of upvote. For that reason I would like to see voting made public again.

New comment by mcn in "The problem with blogging"

mcn — Fri, 27 May 2011 01:44:21 +0000

I think the lack of timeless* articles in content streams -- HN, Reddit, Twitter, etc. -- is a serious problem. I'm imagining a middle-ground between a subreddit and a longform.org for the topics I'm interested in, and think that would be a significant improvement.

The "essays" format or similar can do a decent job of funneling me towards timeless content once I am on a site looking for it (see Peter Norvig's webpage for another example), but it really doesn't address the stream issue.

Good luck with your tweeting experiment.

*I'm really thinking of something weaker than timelessness: worthwhile over a matter of years, at least.

New comment by mcn in "Lisp Lacks Visual Cues"

mcn — Mon, 23 May 2011 08:52:31 +0000

Someone (sorry for not noting your name) suggested dimming/graying the parentheses in lisp modes and gave this elisp snippet to do it. I find that I prefer reading lisp with dimmed parentheses.

(defface paren-face '((((class color) (background dark)) (:foreground "grey20")) (((class color) (background light)) (:foreground "grey70"))) "Face used to dim parentheses.")

(add-hook 'scheme-mode-hook (lambda () (font-lock-add-keywords nil '(("(\\|)" . 'paren-face)))))

I also came across a blog post[1] which includes a slightly more complete solution.

http://briancarper.net/blog/492/

New comment by mcn in "Woman removes SIM card from smart energy meter, uses $193k of 3G data"

mcn — Tue, 03 May 2011 17:36:19 +0000

Agreed. It appears that she was averaging a $4k+/day bill -- it shouldn't take 4 months to notice that something is wrong with that.

New comment by mcn in "Tell HN: Please bring back comment scores"

mcn — Tue, 26 Apr 2011 15:40:01 +0000

Removing comment scores seems to have increased the amount of mediocre/poor comments around contested topics: I am noticing more more brother/sister comments that are basically reiterating each other and more debates that veer to uncontrollable levels of indentation when the key points were already covered in the top level post and first child.

The relative absence of these black holes of discussion is one of the things that brought me to HN in the first place, and I think that showing comment scores discouraged them on multiple levels. Public upvoting lets people express their view on the topic without posting points similar to those already expressed. When two comments have a lopsided point spread it lets one "side" of the debate feel more comfortable letting the other have the last word.

New comment by mcn in "The Lisp Curse"

mcn — Mon, 18 Apr 2011 00:42:11 +0000

One consequence of the parenthesis and prefix notation is that n-ary operators are idiomatic in lisps. So, the above example would more likely be written:

(print (++ a " " b " " c " "))

New comment by mcn in "Is programming the new math? "

mcn — Mon, 11 Apr 2011 00:54:14 +0000

If my junior high and high school curriculum didn't even make it through precalculus after the typical six years of dedicated math courses, often featuring nightly homework, I would probably wretch at the mention of math too.

I suspect that your students had already learned that they weren't going to use the covered material, even within subsequent math classes -- by being taught the same material year after year.

New comment by mcn in "Grokking Org-mode and putting it in charge"

mcn — Fri, 08 Apr 2011 14:23:53 +0000

Emacs could be a stumbling block, but you don't need to learn lisp to use org mode. I initially ran into the same problem of getting to the point where I could follow a tutorial, so here's a 2 minute quick start. The next paragraph guides you through making your first org outline, and should leave you with the tip of the iceberg and a snorkel.

Once you have org installed, hit "Control-x f" to open/create a file, and name one "orgtest.org". Type "* first header" -- if it doesn't turn blue, type "alt-x org-mode" to turn on org-mode. Now type "alt-enter", then hit tab a few times -- it should change the number of stars (level of indentation). Leave it with two stars. Type "take dog to park" on that line, now hit "control-c control-t" several times. It should cycle through a todo/done tag. Hit a regular enter this time, and type "remember your frisbee". Type "control-c control-s"; a calender should pop up, click on tomorrow's date. Now type shift-tab a few times and watch the outline fold/unfold.

Note that the date line and TODO tag are plain text, as is the entire .org file. It could be helpful to think of org-mode as a code editor and interpreter for org markup.

I believe the above should take you to the point where you can follow org-mode tutorials and reference material, although if you decide to really dive in you should probably take some time to learn emacs as well.