On Mar 24, 6:52 pm, "mkppk" <[EMAIL PROTECTED]> wrote:
>
> Its just that I would rather not reinvent the wheel (or read old C
> code)..
>
Wouldn't we all!
Here is the basic structure of a pyparsing solution. The parsing part
isn't so bad - the real problem is the awful ParseONUS routine in C.
Plus things are awkward since the C program parses right-to-left and
then reverses all of the found fields, and the parser I wrote works
left-to-right. Still, this grammar does most of the job. I've left
out my port of ParseONUS since it is *so* ugly, and not really part of
the pyparsing example.
-- Paul
from pyparsing import *
# define values for optional fields
NoAmountGiven = ""
NoEPCGiven = ""
NoAuxOnusGiven = ""
# define delimiters
DOLLAR = Suppress("$")
T_ = Suppress("T")
A_ = Suppress("A")
# field definitions
amt = DOLLAR + Word(nums,exact=10) + DOLLAR
onus = Word("0123456789A- ")
transit = T_ + Word("0123456789-") + T_
epc = oneOf( list(nums) )
aux_onus = A_ + Word("0123456789- ") + A_
# validation parse action
def validateTransitNumber(t):
transit = t[0]
flds = transit.split("-")
if len(flds) > 2:
raise ParseException(0, "too many dashes in transit number",
0)
if len(flds) == 2:
if len(flds[0]) not in (3,4):
raise ParseException(0, "invalid dash position in transit
number", 0)
else:
# compute checksum
ti = map(int,transit)
ti.reverse() # original algorithm worked with reversed data
cksum = 3*(ti[8]+ti[5]+ti[2]) + 7*(ti[7]+ti[4]+ti[1]) +
ti[6]+ti[3]+ti[0]
if cksum%10 != 0:
raise ParseException(0, "transit number failed checksum",
0)
return transit
# define overall MICR format, with results names
micrdata =
Optional(aux_onus,default=NoAuxOnusGiven).setResultsName("aux_onus") +
\
Optional(epc,default=NoEPCGiven).setResultsName("epc") +\
transit.setParseAction(validateTransitNumber).setResultsName("transit")
+ \
onus.setResultsName("onus") + \
Optional(amt,default=NoAmountGiven).setResultsName("amt")
+ \
stringEnd
import re
def parseONUS(tokens):
tokens["csn"] = ""
tokens["tpc"] = ""
tokens["account"] = ""
tokens["amt"] = tokens["amt"][0]
onus = tokens.onus
# remainder omitted out of respect for newsreaders...
# suffice to say that unspeakable acts are performed on
# onus and aux_onus fields to extract account and
# check numbers
micrdata.setParseAction(parseONUS)
testdata = file("checks.csv").readlines()[1:]
tests = [(flds[1],flds) for flds in map(lambda
l:l.split(","),testdata)]
def verifyResults(res,csv):
def match(x,y):
print (x==y and "_" or "X"),x,"=",y
Ex,MICR,Bank,Stat,Amt,AS,TPC,TS,CSN,CS,ACCT,AS,EPC,ES,ONUS,OS,AUX,AS,Tran,TS
= csv
match(res.amt,Amt)
match(res.account,ACCT)
match(res.csn,CSN)
match(res.onus,ONUS)
match(res.tpc,TPC)
match(res.epc,EPC)
match(res.transit,Tran)
for t,data in tests:
print t
try:
res = micrdata.parseString(t)
print res.dump()
if not(data[0] == "No"):
print "Passed expression that should have failed"
verifyResults(res,data)
except ParseException,pe:
print "<parse failed> %s" % pe.msg
if not(data[0] == "Yes"):
print "Failed expression that should have passed"
print
--
http://mail.python.org/mailman/listinfo/python-list
