Andrew Cooke | Contents | Latest | RSS | Previous | Next

C[omp]ute

Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

Personal Projects

Choochoo Training Diary

Last 100 entries

[Programming] React Leaflet; AliExpress Independent Sellers; Applebaum - Twilight of Democracy; [Politics] Back + US Elections; [Programming,Exercise] Simple Timer Script; [News] 2019: The year revolt went global; [Politics] The world's most-surveilled cities; [Bike] Hope Freehub; [Restaurant] Mama Chau's (Chinese, Providencia); [Politics] Brexit Podcast; [Diary] Pneumonia; [Politics] Britain's Reichstag Fire moment; install cairo; [Programming] GCC Sanitizer Flags; [GPU, Programming] Per-Thread Program Counters; My Bike Accident - Looking Back One Year; [Python] Geographic heights are incredibly easy!; [Cooking] Cookie Recipe; Efficient, Simple, Directed Maximisation of Noisy Function; And for argparse; Bash Completion in Python; [Computing] Configuring Github Jekyll Locally; [Maths, Link] The Napkin Project; You can Masquerade in Firewalld; [Bike] Servicing Budget (Spring) Forks; [Crypto] CIA Internet Comms Failure; [Python] Cute Rate Limiting API; [Causality] Judea Pearl Lecture; [Security, Computing] Chinese Hardware Hack Of Supermicro Boards; SQLAlchemy Joined Table Inheritance and Delete Cascade; [Translation] The Club; [Computing] Super Potato Bruh; [Computing] Extending Jupyter; Further HRM Details; [Computing, Bike] Activities in ch2; [Books, Link] Modern Japanese Lit; What ended up there; [Link, Book] Logic Book; Update - Garmin Express / Connect; Garmin Forerunner 35 v 230; [Link, Politics, Internet] Government Trolls; [Link, Politics] Why identity politics benefits the right more than the left; SSH Forwarding; A Specification For Repeating Events; A Fight for the Soul of Science; [Science, Book, Link] Lost In Math; OpenSuse Leap 15 Network Fixes; Update; [Book] Galileo's Middle Finger; [Bike] Chinese Carbon Rims; [Bike] Servicing Shimano XT Front Hub HB-M8010; [Bike] Aliexpress Cycling Tops; [Computing] Change to ssh handling of multiple identities?; [Bike] Endura Hummvee Lite II; [Computing] Marble Based Logic; [Link, Politics] Sanity Check For Nuclear Launch; [Link, Science] Entropy and Life; [Link, Bike] Cheap Cycling Jerseys; [Link, Music] Music To Steal 2017; [Link, Future] Simulated Brain Drives Robot; [Link, Computing] Learned Index Structures; Solo Air Equalization; Update: Higher Pressures; Psychology; [Bike] Exercise And Fuel; Continental Race King 2.2; Removing Lowers; Mnesiacs; [Maths, Link] Dividing By Zero; [Book, Review] Ray Monk - Ludwig Wittgenstein: The Duty Of Genius; [Link, Bike, Computing] Evolving Lacing Patterns; [Jam] Strawberry and Orange Jam; [Chile, Privacy] Biometric Check During Mail Delivery; [Link, Chile, Spanish] Article on the Chilean Drought; [Bike] Extended Gear Ratios, Shimano XT M8000 (24/36 Chainring); [Link, Politics, USA] The Future Of American Democracy; Mass Hysteria; [Review, Books, Links] Kazuo Ishiguro - Never Let Me Go; [Link, Books] David Mitchell's Favourite Japanese Fiction; [Link, Bike] Rear Suspension Geometry; [Link, Cycling, Art] Strava Artwork; [Link, Computing] Useful gcc flags; [Link] Voynich Manuscript Decoded; [Bike] Notes on Servicing Suspension Forks; [Links, Computing] Snap, Flatpack, Appimage; [Link, Computing] Oracle is leaving Java (to die); [Link, Politics] Cubans + Ultrasonics; [Book, Link] Laurent Binet; VirtualBox; [Book, Link] No One's Ways; [Link] The Biggest Problem For Cyclists Is Bad Driving; [Computing] Doxygen, Sphinx, Breathe; [Admin] Brokw Recent Permalinks; [Bike, Chile] Buying Bearings in Santiago; [Computing, Opensuse] Upgrading to 42.3; [Link, Physics] First Support for a Physics Theory of Life; [Link, Bike] Peruvian Frame Maker; [Link] Awesome Game Theory Tit-For-Tat Thing; [Food, Review] La Fabbrica - Good Italian Food In Santiago; [Link, Programming] MySQL UTF8 Broken; [Link, Books] Latin American Authors

© 2006-2017 Andrew Cooke (site) / post authors (content).

Snobol Like Matching in Python

From: "andrew cooke" <andrew@...>

Date: Tue, 30 Dec 2008 13:23:08 -0300 (CLST)

Found this while looking for info for work; need to go back when I have
more time and read it further.

http://www.wilmott.ca/python/patternmatching.html

Particularly like the array subset syntax for specifying repeats:
  * : [0:]
  + : [1:]
  ? : [0:1]
etc

Andrew

Rethinking Parsing

From: "andrew cooke" <andrew@...>

Date: Fri, 2 Jan 2009 21:56:30 -0300 (CLST)

I'm getting the urge to write another parsing library :o)

I like what was done in the work above and it seems like it could be
easily(?) made more general.  The existing package takes a list of
characters and generates labelled words.  It seems to me that could be
changed to generate a list of words.  Or even a list of arbitrary objects.
 And it also seems to me that the parsers could be changed to match not
just lists of characters, but lists of arbitrary objects.

If you do that then it can eat its own tail - you can have various levels
of parsers.  The way I see it, these constrict different levels in the
AST.

Does that make sense?  How is this different from normal?  There's a
slight difference in implementation - the source itself stores the new
stream, rather than it being returned by the parser.  I have no idea if
this is an improvement or not.  I need to read the code for the matcher
again.  Does it help with backtracking?  Is it just an implementation
detail?  What's wrong with returning the match?

Andrew

Stupid

From: "andrew cooke" <andrew@...>

Date: Sat, 3 Jan 2009 16:54:50 -0300 (CLST)

Prev comments were somewhat stupid.

With recursive descent the combinators construct a guided path down to the
matching against characters.  So there's no layered streams of characters
and tokens.

So what does the code in the paper give you?

First of all, it has some nice ideas about syntax.  Most of all - that by
using Python objects rather than just functions, you have  a lot more
freedom to play around.

Second, backtracking.

In addition, something that has always bugged me, and which I'd like to
improve: better diagnostics.

Andrew

Slice Mechanics

From: "andrew cooke" <andrew@...>

Date: Sat, 3 Jan 2009 20:43:23 -0300 (CLST)

I just ran some simple tests.  If the appropriate __ methods are
implemented then:

foo[1] calls foo.__getitem__(1)
foo[1:2] calls foo.__getslice(1, 2)
foo[1:2:3] calls foo.__getitem(slice(1,2,3))

but if __getslice__ is missing then foo[1:2} calls
foo.__getitem(slice(1,2,None)) - that means that getitem handles all
calls, but the single arg case is passed a simple value.

The slice() object looks like an ordinary object with start, stop, step
and indices attributes.

Andrew

More Ideas

From: "andrew cooke" <andrew@...>

Date: Sun, 4 Jan 2009 10:55:13 -0300 (CLST)

- Track deepest search via source for debugging

- Matching returns matched value or [value] or [(name, value)].  Latter
can be used to construct dictionaries.  Can return anything (via function)
but we support those via nice syntax.

- Node class that can be constructed from lists of (name, value). 
Implements iterator (all values) and attribute based (named values)
interface.  Several representations.  str returns matched string
(including unlabelled values).  Tree returns ascii format tree (with named
values only).

Andrew

Comment on this post