python->pascal

[Barov4e]

Hi guys,
I have a problem converting a very simple software from python to pascal. I haven't use python before and that is the reason I can't understand some codes. I am attaching the source. But here is what I can't understand:

def nextDecode(arg1):
    global index
    result = 0
    for i in range(arg1):
        rc = shouldDecodeStep(index)
        if (rc == -1):
            break
        else:
            if rc:
                result = result | 1 << i
            index += 1
    return result - (1 << arg1 - 1)

First, which is the body of "for" loop? And what does this:

result = result | 1 << i

 try:
        val1 = textbuffer[lindex / 7]
        val2 = lindex % 7
        return (val1 >> val2 & 1 == 1)
    except Exception, e:
        return -1

I suppose this is try/except in pascal ?!

 result = ''

What this means? And in nextDecode result is integer.

arg1 & 1 << i != 0

What does this mean?
And where is the main function of this ?! ... or it hasn't