my first class: Args
in.aqua.scribis at nl.invalid
Sat Aug 28 22:49:37 CEST 2004
Thanks for your comments. Especially the thing about using
try/except is very useful. I knew about it, but just didn't
"see" I could use it. Something I have to get used to.
More comments below.
Scott David Daniels wrote:
> > def __iter__(self):
> > "iterator set-up"
> ^^ useless docstring -- presume the reader knows python
> > if self._argc == 0 and sys.stdin.isatty():
> > self.usage()
> > if self._argc == 0:
> > self.infile = '<stdin>'
> > self._stdin = 1
> > self._in = sys.stdin
> > else:
> > self.infile = self._argv.pop(0)
> > self._argc -= 1
> > self._stdin = 0
> > self._in = open(self.infile, 'r')
> > return self
> self.infile = self._argv.pop(0)
> except IndexError:
> if sys.stdin.isatty():
> self.usage() # Doesn't return
> self.infile = '<stdin>'
> self._stdin = True
> self._in = sys.stdin
> self._stdin = False
> self._in = open(self.infile, 'r')
> return self
This is the only instance I didn't follow your recommendation to
use try/except. It is a binary choice: do we use files given on
the command line or stdin? Neither is more natural than the
other. Also, it splits up lines of code that belong together.
Here is my re-write:
self.infile = self._argv.pop(0)
self._in = open(self.infile, 'r')
self._stdin = False
self.usage() # Doesn't return
self.infile = '<stdin>'
self._in = sys.stdin
self._stdin = True
The exceptional case is there be no input, and the simplest test
here seems to be a simple if-statement.
> > return self.next()
> ^^ Loop rather than recur unless you have a good reason.
Your solution looks much better.
> > if __name__ == '__main__':
> > ...
> ^^ also nicer to be able to test from included version:
> def demo():
> if __name__ == '__main__':
That doesn't seem very useful. It depends on command line
arguments. If they are missing, it does a sys.exit(), probably
not what you want unless you run the module stand-alone.
Peter Kleiweg L:NL,af,da,de,en,ia,nds,no,sv,(fr,it) S:NL,de,en,(da,ia)
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