Re: wxPython vs. pyQt

[Andrew E]

Hans-Peter Jansen wrote:
..
While in PyQt world, I found these advantages:
 + conceptually vastly superior
 + powerful api/widgets/features
 + fast as hell due to the efficient binding of a quite efficient lib
 + cool tools, that are unicode/translation aware
 + very efficient programming environment/unbeatable productivity
While this sounds like the average sales talk, I will try to backup these
claims a bit:
> ..
I've been a wx user since around 1999 and overall I like it. It annoys 
me a *lot* sometimes, but as Qt was always prohibitively expensive for 
commercial development, it was the only real option.

The key question from my point of view is: can I write commercial 
sell-if-I-want-to applications using Qt? If it is GPL, then I guess the 
answer is 'no'?

Andrew
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Re: wxPython vs. pyQt

[Andrew E]

John J. Lee wrote:
The key question from my point of view is: can I write commercial
sell-if-I-want-to applications using Qt? If it is GPL, then I guess
the answer is 'no'?

Yes, you can write commercial apps.  It's multi-licensed (commercial,
GPL, etc.): you get to pick the license(s) you want to use.  Read the
licenses.
PyQt's licensing follows Qt's very closely, so no real complications
there.  Note PyQt (including a Qt license for use only with PyQt) is
actually far cheaper than Qt alone (if you buy Blackadder).
ok, thanks. I've just had a quick browse of the licence notes at the 
PyQt website.

I guess I meant: "can I write commercial closed-source software *without 
paying anything for Qt" - to which I sounds like the answer is 
definitely "No" :)

Andrew
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module to parse "pseudo natural" language?

[Andrew E]

Hi all

I've written a python program that adds orders into our order routing
simulation system. It works well, and has a syntax along these lines:

  ./neworder --instrument NOKIA --size 23 --price MARKET --repeats 20

etc

However, I'd like to add a mode that will handle, say:

  ./neworder buy 23 NOKIA at MKT x 20

I could enter several orders either by running multiple times, or use a
comma-separated approach, like:

  ./neworder buy 23 NOKIA at MKT on helsinki, sell 20 NOKIA at market on
helsinki

The thing about this is that its a "tolerant" parser, so all of these
should also work:

  # omit words like "at", "on"
  ./neworder buy 23 NOKIA mkt helsinki

  # take any symbol for helsinki
  ./neworder buy 23 mkt helsinki

  # figure out that market=helsinki
  ./neworder buy 23 NOKIA at market price


I've started writing a simple state-based parser, usage like:

  class NaturalLanguageInsructionBuilder:

def parse( self, arglist ):
  """Given a sequence of args, return an Instruction object"""
  ...
  return Instruction( instrument, size, price, ... )


  class Instruction:
"""encapsulate a single instruction to buy, sell, etc"""

def __init__( self, instrument, size, price, ... ):
  ...


This doesn't work yet, but I know with time I'll get there.

Question is - is there a module out there that will already handle this
approach?

Thanks for any suggestions :)

Andrew
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Re: sscanf needed

[Andrew E]

Uwe Mayer wrote:
> Hi,
> 
> I've got a ISO 8601 formatted date-time string which I need to read into a
> datetime object.
> Is there a shorter way than using regular expressions? Is there a sscanf
> function as in C?

in addition to the other comments...

I like re, because it gives me the most control. See below.


import re
import datetime

class Converter:

def __init__( self ):
self.isoPattern = re.compile( "(\d\d\d\d)-(\d\d)-(\d\d)[tT
](\d\d):(\d\d):(\d\d)" )

def iso2date( self, isoDateString ):
match = self.isoPattern.match( isoDateString )
if not match: raise ValueError( "Not in ISO format: '%s'" %
isoDateString )

return datetime.datetime(
int(match.group(1)),
int(match.group(2)),
int(match.group(3)),
int(match.group(4)),
int(match.group(5)),
int(match.group(6))
)

c = Converter()


def demo( iso ):
try:
date = c.iso2date( iso )
print "Input '%s' -> datetime: %s" % ( iso, date )
except ValueError, e:
print str(e)

demo( "2005-04-21T12:34:56" )
demo( "2005-04-21 12:34:57" )
demo( "2005-04-2 12:34:57" )


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