Language Work Benches in Py

[yoda]

Hi,
I recently read Martin Fowler's article on language workbenches and
domain specific
languages(http://www.martinfowler.com/articles...orkbench.html).
I then had the pleasure of reading Rainer Jowsig's implementation of
the sample in Lisp(http://lispm.dyndns.org/news?ID=NEWS-2005-07-08-1).

The lisp code was so sexy that I was inspired to write a sample in
Python. I'm relatively new to coding in Python so I'd love any barbs,
comments or criticisms about the code. You can find my article here :
(http://billionairebusinessman.blogsp...hands-in.html).

I also made a screen cast of the same
(http://openenterpriseafrica.com/neo/...ython.wmv.bz2).
Unfortunately, I had to make it using a windows machine so it's encoded
as wmv. (If anyone finds it useful and is inspired to encode it in a
more palatable format e.g. mov, I'd be honoured to create a torrent and
host it)

[yoda]

Re: Language Work Benches in Py

I realize that I forgot to post the sample code:). Below is my
implementation:

#DSL data
#12345678901234 567890123456789 012345678901234 567890123456789 0,

dsldata=(
'SVCLFOWLER 10101MS01200503 13............. ............',
'SVCLHOHPE 10201DX03200503 15............. ...........',
'SVCLTWO x10301MRP220050 329............ ............... ...',
'USGE10301TWO x50214..7050329 ............... ............... .')

#Class mappings
Mappings={'svcl ':{
(4,18):'Custome rName',
(19,23):'Custom erID',
(24,27) :'CallTypeCode' ,
(28,35) : 'DateOfCallStri ng'},
'usge':{(4,8) :'CustomerID',
(9,22):'Custome rName',
(30,30):'Cycle' ,
(31,36): 'ReadDate'}}


def generateClass(d ata):
'generate the class and instance with attributes'

className = data[:4].lower() #1)
mappingData= Mappings[className] #2)
class Klass:pass #3)
Klass. __name__=classN ame #4)
# print Klass

for key in mappingData.key s(): #5)
fielddata=data[key[0]:key[1]]
print 'actual data->',fielddata
setattr(Klass,m appingData[key],fielddata) #6)
return Klass


def parseData():
'parse the data and generate a list of objects'
classes= [generateClass(i tem) for item in dsldata]
return classes

def printKlassData( Klass):
print Klass
for key in Klass.__dict__:
print ('attr->%s value->%s')%(key,Klas s.__dict__[key])

if __name__=='__ma in__':
for Klass in parseData():
printKlassData (Klass)