flowcharting is automatic for Python via preprocessor

Larry Bates lbates at swamisoft.com
Tue Aug 3 01:20:50 CEST 2004

Small changes eliminate the need for flow
diagram (IMHO).

def f():
    """Demonstration of flow diagrams."""
    for i in range(100):
        r=i % 3
        if r == 2:
            print 'Remainder two, stopping loop'

        if r == 1:
            if i < 10:  print 'Less than ten'
            else:       print 'Greater than ten'

        print 'Multiple of three'

While I realize your example function was just that
and example (because you could never even get to some
of the branches because it exits when i=5).  I see a
lot of code with nested if/elif constructs that are
unnecessary which add to the difficulty of
"deciphering" what is going on.

Larry Bates
Syscon, Inc.

<barnesc at onid.orst.edu> wrote in message
news:mailman.1069.1091487166.5135.python-list at python.org...
> I like your idea.
> It is easy to get lost inside in eg a multiply nested if statement in a
> multiply nested for loops, inside a try block.
> Sometimes one can split such code into separate functions, and this makes
> code cleaner.  Sometimes not.
> However, the real issue is how the eye parses code.
> It's really inefficient to scan a whole page of code line by line to
> where loops, branches, continues, and breaks occur.
> I think your visual diagrams could help, if they are:
> 1. Semantically cleaner.
>    IMO, there is too much detail in the flow diagrams.
>    (See http://www.getcet.org/images/ex3.png).
>    A minimal amount of detail is easier to parse with the eye.
>    See http://oregonstate.edu/~barnesc/temp/flow.pdf for a cleaner
>    example I came up with.  This doesn't have arrows all over the
>    place (and hence may not be a flow diagram), but it does help
>    point out the relevant control structures.
> 2. Integrated into a code editor.
>    I could see this being a new code editor fad, like collapsable
>    functions and classes.
>    It could be quite useful, if the amount of visual information
>    is kept minimal, so that the coder is not distracted during
>    coding.
>    If the flow diagrams are not integrated into an editor, I don't
>    think many coders will use them.
> Perhaps editors already do this.
>  - Connelly

More information about the Python-list mailing list