Reading Until EOF

[Scott Brady Drummonds]

Hi, everyone,

I'm a Python novice and would love some tips on how I should perform the
following task: I'd like to have my Python script read objects (using their
constructors) and terminate gracefully when an EOF is encountered.  My first
attempt looked like this:

  #  This is enclosed in a 'try' block
  file = open(...)
  while 1:
    #  The Object constructor raises an exception for end-of-file
    object = Object(file)
    self.list = self.list + [object]

However, I'm not entirely comfortable having the Object constructor raise an
exception when the end-of-file is hit.  Per my experience with C++, this
does not qualify as "exceptional behavior".  Frankly, it is accepted.  I'd
like to save the exceptions for true exceptions.  My next guess:

  #  This is enclosed in a 'try' block
  file = open(...)
  while object = Object(file):
    self.list = self.list + [object]

With this implementation, the file reading stops both with an exception
(raised by a parsing error, as an example) and when the Object constructor
returns something that makes the while conditional fail.  However, therein
lies the rub: I don't know how to do this in Python.

Is there a way for me to make the second implementation work?  Is there an
"empty" operator in Python that I could overload?  Can I have a constructor
return 'null'?

Thanks!
Scott

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