import string, sys, os

class Respondent: pass

class Interval: pass

# these are the attributes to extract from the respondents file
resattrs = [
    ['id', 1, 8],
    ['wntanotr', 9360, 9360],
    ['spwntkid', 9361, 9361],
    ['intnothr', 9362, 9362],
    ['ager', 10880, 10881],
    ['rcurpreg', 11275, 11275],
    ['pregnum', 11276, 11277],
    ['parity', 11290, 11291],
    ['intent', 12244, 12244],
    ['addexp', 12245, 12247],
]

# these are the attributes to extract from the interval file
intattrs = [
    ['id', 1, 8],
    ['pregordr', 9, 10],
    ['nbrnlv', 14, 14],
    ['wks_preg', 22, 23],
    ['kidssex1', 95, 95],
    ['kidssex2', 151, 151],
    ['outcome', 291, 291],
    ['prglngth', 292, 293],
    ['sex1', 325, 325],
    ['sex2', 326, 326],
]

def process_respondent(line):
# take a line from the respondent file and build a Respondent object
    res = Respondent()
    for (attr, start, end) in resattrs:
        setattr(res, attr, line[start-1:end])
    return res

def process_interval(line):
# take a line from the interval file and build an Interval object
    inter = Interval()
    for (attr, start, end) in intattrs:
        setattr(inter, attr, line[start-1:end])
    return inter

def process_line(line, constructor, attrs):
# here's how I could have generalized process_respondent and
# process_interval
    obj = constructor()
    for (attr, start, end) in attrs:
        setattr(obj, attr, line[start-1:end])
    return obj



def main(name):

    # process the respondent file (uncompress with gunzip)
    fp = os.popen('gunzip --to-stdout respnd95.asc.gz', 'r')
    for line in fp:
        res = process_respondent(line)
        # OR res = process_line(line, Respondent, resattrs)
        print res.id
    fp.close()

    # process the interval file (uncompressed text)
    fp = open('interv95.asc', 'r')
    for line in fp:
        inter = process_interval(line)
        # OR inter = process_line(line, Interval, intattrs)
        print inter.id
    fp.close()
    
if __name__ == '__main__':
    main(*sys.argv)