Python-list Digest, Vol 32, Issue 300

[Khoa Nguyen]

> Optional(f1SpecificFormat) + "," + Optional(f2SpecificFormat) + "," + ...
> and so on.

Thanks for your input again. This is exactly what I am trying.  The
only thing is it can get ugly if the number of fields are many -- I
have about 61 fields right now. Just wondering if  there is a
"cleaner" approach.

Thanks,
Khoa

==================
from pyparsing import *

DELIM = Suppress('&')
RECORD_END = Suppress(';')
f1 = Literal('a')
f2 = Literal('b')
f3 = Word(alphanums+'_-.')

common = f1
extended = Optional(DELIM + Optional(f2))  \
                   + Optional(DELIM + Optional(f3))

g = common + Optional(extended) + RECORD_END

def parse(record):
        result = g.parseString(record)
        print result

if __name__=='__main__':
        good = ['a;', 'a&&c-123;', 'a&b;', 'a&b&c;', 'a&b&c-123-af;']
        bad = [ ';',            # required field missing
                        'a',            # RECORD_END missing
                        'b&c;',         # required field missing
                        'a&c&b;',   # Incorrect order
                        'x123&a&b;' # Incorrect order
                  ]
        for r in good + bad:
                try:
                        parse(r)
                except ParseException, err:
                        print err.line
                        print " "*(err.column-1) + "^"
                        print err
                        continue
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