| Andrew Cooke | Contents | Latest | RSS | Twitter | 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

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.

C-ORM: docs, API.

Last 100 entries

TP-Link TL-WR841N DNS TCP Bug; TP-Link TL-WR841N as Wireless Bridge; Sending Email On Time; Maybe run a command; Sterile Neutrinos; Strawberry and Banana Jam; The Best Of All Possible Worlds; Kenzaburo Oe: The Changeling; Peach Jam; Taste Test; Strawberry and Raspberry Jam; flac to mp3 on OpenSuse 42.1; Also, Sebald; Kenzaburo Oe Interview; Otake (Kitani Minoru) move Black 121; Is free speech in British universities under threat?; I am actually good at computers; Was This Mansplaining?; WebFaction / LetsEncrypt / General Disappointment; Sensible Philosophy of Science; George Ellis; Misplaced Intuition and Online Communities; More Reading About Japan; Visibilty / Public Comments / Domestic Violence; Ferias de Santiago; More (Clearly Deliberate); Deleted Obit Post; And then a 50 yo male posts this...; We Have Both Kinds Of Contributors; Free Springer Books; Books on Religion; Books on Linguistics; Palestinan Electronica; Books In Anthropology; Taylor Expansions of Spacetime; Info on Juniper; Efficient Stream Processing; The Moral Character of Crypto; Hearing Aid Info; Small Success With Go!; Re: Quick message - This link is broken; Adding Reverb To The Echo Chamber; Sox Audio Tools; Would This Have Been OK?; Honesty only important economically before institutions develop; Stegangraphy via PS4; OpenCL Mess; More Book Recommendations; Good Explanation of Difference Between Majority + Minority; Musical Chairs - Who's The Privileged White Guy; I can see straight men watching this conversation and laffing; Meta Thread Defending POC Causes POC To Close Account; Indigenous People Of Chile; Curry Recipe; Interesting Link On Marginality; A Nuclear Launch Ordered, 1962; More Book Recs (Better Person); It's Nuanced, And I Tried, So Back Off; Marx; The Negative Of Positive; Jenny Holzer Rocks; Huge Article on Cultural Evolution and More; "Ignoring language theory"; Negative Finger Counting; Week 12; Communication Via Telecomm Bids; Finding Suspects Via Relatives' DNA From Non-Crime Databases; Statistics and Information Theory; Ice OK in USA; On The Other Hand; (Current Understanding Of) Chilean Taxes / Contributions; M John Harrison; Playing Games on a Cloud GPU; China Gamifies Real Life; Can't Help Thinking It's Thoughtcrime; Mefi Quotes; Spray Painting Bike Frame; Weeks 10 + 11; Change: No Longer Possible To Merge Metadata; Books on Old Age; Health Tree Maps; MRA - Men's Rights Activists; Writing Good C++14; Risk Assessment - Fukushima; The Future of Advertising and Surveillance; Travelling With Betaferon; I think I know what I dislike so much about Metafilter; Weeks 8 + 9; More; Pastamore - Bad Italian in Vitacura; History Books; Iraq + The (UK) Governing Elite; Answering Some Hard Questions; Pinochet: The Dictator's Shadow; An Outsider's Guide To Julia Packages; Nobody gives a shit; Lepton Decay Irregularity; An Easier Way; Julia's BinDeps (aka How To Install Cairo); Good Example Of Good Police Work (And Anonymity Being Hard); Best Santiago Burgers

© 2006-2015 Andrew Cooke (site) / post authors (content).

Pytyp - Extending Python Types for Declarative Code

From: andrew cooke <andrew@...>

Date: Fri, 20 May 2011 08:57:56 -0400

I finished and released v2.0 of the Pytyp package yesterday.  While I think
it's awesome, I suspect it will never be used.  Because it's not an easy thing
to "sell" - an "embedded domain specific language for type metadata" doesn't
sound very useful, does it?

But I'd encourage you to have a second look.  The main use that I see is in
producing libraries with *declarative* APIs.  Pytyp lets you describe what
data should look like.

The perfect example is converting JSON to Python classes.  Here is code using
a library built on top of pytyp:

  >>> class Example():
  ...     def __init__(self, foo):
  ...         self.foo = foo
  ...     def __repr__(self):
  ...         return '<Example({0})>'.format(self.foo)

  >>> class Container():
  ...     def __init__(self, *examples:[Example]):
  ...         self.examples = examples
  ...     def __repr__(self):
  ...         return '<Container({0})>'.\
  ...             format(','.join(map(repr, self.examples)))

  >>> loads = make_loads(Container)
  >>> loads('[{"foo":"abc"}, {"foo":"xyz"}]')
  <Container(<Example(abc)>,<Example(xyz)>)>

All the user needs to do is:
 1 - Ask for the class required in make_loads()
 2 - Add type annotations to constructors (eg *examples:[Example])

That may not seem like much, but if you implement this within pytyp, which
tries to provide a consistent framework for types, you get - "for free" -
things like the possibility to express alternative types.

So if you don't know if the JSON data encodes Container or OtherClass, you can
use:

  >>> loads = make_loads(Alt(Container,OtherClass))

and the library will automatically "do the right thing".

And that is what I mean by "a declarative API".

Andrew

Paper - http://www.acooke.org/pytyp.pdf
Code - http://www.acooke.org/pytyp

Comment on this post