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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.

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Lepl parser for Python.

Colorless Green.

Photography around Santiago.

SVG experiment.

Professional Portfolio

Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

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Those little tab things on the side of jet engines; Re: Python's sad, unimaginative Enum; Some explanation; Printing binary trees sideways; About "Python's sad, unimaginative Enum"; Atoms in python; Some good feedback here; Frustration Understood; I agree with you #nt; What would be imaginative?; Re: Enum; this is fucking useless; Enum; Python's sad, unimaginative Enum; Possible Fix; Work, Exhaustion, Vacation; VirtualBox with Centos 6.3 to 6.4, client; Matasano - Programming Lessons Learned; PDF to HTML; Alternate Substitution; Why RSA Works; Trigger; Dreaming of Death; Example: Tracing; Using Coroutines In Protocol Simulations; Python 3.3 Only; Pure Python SHA1 and MD4 Implementations; Ubuntu on VirtualBox; Starting TOR as a service on OpenSuse 12.3; 1001 Albums; Using fail2ban on OpenSuse 12.3; PPPoE on OpenSuse 12.3; Good Article on Unified Physics; It's Police (Carabineros); Linux Software for Listening to and Exploring Music; Android is Pretty Bad; Lucky Number; 3D Printing for Casting; Cover Art for MPDroid; Who'd a thought the French were so bigoted?; PS Input Signal; Small Problem with Roksan K2 Amp; Roksan K2 Amp + ATC SCM7 Speakers; Do What Makes Sense; Re: Arguing About Tests, Still; Arguing About Tests, Still; Images; Good Article on NY Drummers; Related Bug Report; Getting Python 3.3 and Virtualenv Working in OpenSuse 12.3; How I Am; Awesome video about digital audio; The Difference Between Dimensional and Normalized Databases; The rise of the new Chinese bogeyman; Updated Syntax; Very First Steps to C-ORM; The Ideal User Interface For Music Exploration; Can The Republicans Be Saved?; Rate Limiting Calls to EchoNest; Mods to Cache; Comparing UYKFG and UYKFD/E/F; Someone Else is Concerned; EchoNest-based Playlist Generator for MPD; Example Voting Results; A Heavyweight Python Cache; Identifying Artists with EchoNest; Notes on Pregalex / Pregabalina / Lyrica; The Neil Cowley Trio; Drake - Make for Data; A Reliable Python Web Service; Useful Python Date/Time Library?; Need to Sleep, But this is Good; Command Line Set Difference; Little Details...; Linux Command Line Tricks; AutoTools Tutorial; Hangman Tactics; A Tor Proxy Embedded In A Web Page; Tree (Nested Dicts) in Python; Sleeping at Parties; I Know Someone Who Hurts Other People; Light and Tea; Description of the LCS35 Time Capsule Crypto-Puzzle; Re: I can relate to that ...; I can relate to that ...; Re: It's 2012 Why Does My IDE Suck?; My Own Alternative Medicine; Nice explanation of SVM; Why and How Writing Crypto is Hard; Re: It's 2012 Why Does My IDE Suck?; Incremental Regular Expressions; BBC Map Confused at Pole; Social Media: Ground Zero in the Culture War; My Visit to the Psycho Doc; Learning Modern 3D Graphics Programming; Hope you got some crackers to go with the cheese; Re: But how easy would it be ...; But how easy would it be ...; Powerline Freq Fingerprinting of Audio; The Folly of Scientism; Cheese - Because You're Going to Die Anyway

© 2006-2013 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

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