Parsing problems: A journey from a text file to a directory tree

[Michael J. Fromberger]

Hi, John,

Your comments below are all reasonable.  However, I would like to point 
out that the purpose of my example was to provide a demonstration of an 
algorithm, not an industrial-grade solution to every aspect of the 
original poster's problem.  I am confident the original poster can deal 
with these aspects of his problem space on his own.

In article <1190154665.944722.137750 at q3g2000prf.googlegroups.com>,
 John Machin <sjmachin at lexicon.net> wrote:

> [...]
> > .            while new_level < len(state):
> > .                state.pop()
> 
> Hmmm ... consider rewriting that as the slightly less obfuscatory
> 
>     while len(state) > new_level:
>         state.pop()

This seems to me to be an aesthetic consideration only; I'm not sure I 
understand your rationale for reversing the sense of the comparison.  
Since it does not change the functionality, it's hardly worthy of 
complaint, but I don't see any improvement, either.

> A warning message if there are too many "-" characters might be a good
> idea:
> 
> [foo]
> |-bar
> |-zot
> |---plugh

Perhaps so.  Again, the original poster will have to decide what should 
be the correct response to input of this sort; at present, the 
implementation is tolerant of such variations, without loss of 
generality.

> And if the input line matches neither regex?

I believe it should be clear that such lines are ignored.  Again, this 
is an opportunity for the original poster to determine an alternative 
response -- perhaps an exception could be raised, if that is his desire.  
The problem specification did not constrain this case.

> > To call this, pass a file-like object to parse_folders(), e.g.:
> >
> > test1 = '''
> > [New client].
> 
> Won't work with the dot on the end.

My mistake.  The period was a copy-and-paste artifact, which I missed.

Cheers,
-M

-- 
Michael J. Fromberger             | Lecturer, Dept. of Computer Science
http://www.dartmouth.edu/~sting/  | Dartmouth College, Hanover, NH, USA