[Python-ideas] adding possibility for declaring a function in Matlab's way

[Bruce Leban]

Before suggesting "improvements" to Python (or anything else for that
matter), it's helpful to identify exactly what problem you are trying to
solve. I don't see one. And having multiple entirely different ways to do
things for no good reason mean code is harder to read. Google TOOWTDI for
more info.

If you love this paradigm I suggest you write it this way:

def foo():
  global result
  result = None
  if bar() is not None:
    raise UnnecessaryException
  return result
def bar():
  pass # real code goes here


--- Bruce
New Puzzazz newsletter: http://j.mp/puzzazz-news-2011-02



On Fri, Feb 11, 2011 at 7:48 PM, Géza <kgeza7 at gmail.com> wrote:

> It would be nice if you could write a function header like this (besides,
> of course, the current way):
>
> def result=functionname(params):
>      ...
>      result=something
>
> This would suffice for most functions, since you usually return one type of
> value, and it can be very convenient in certain cases. This is the way it is
> done e.g. in Matlab, which also has a huge user base.
>
> Some more details to the idea:
> - The return values are initialized to None.
> - Setting the return values does not need to be the last line in the
> function.
> - You can use the "return" statement just as before, but without arguments,
> to return from anywhere in the code.
> - If you specify arguments to the "return" statement, Python stops with an
> exception.
> - The return value can be a tuple: def (result1, result2,
> result3)=functionname(parameters)
>
> Some advantages:
> - You can easily see what the function returns, without having to read the
> function body, or hoping to find it in the comments.
> - You can initialize the return values (if None is not good enough), and
> then care about the cases where they change.
> - If you change the setup of the return value (e.g. insert a new item into
> the tuple), you do not need to change the "return" statement at possibly
> several places in the function body.
> - It is very easy to write the function call prototype: just copy the
> function declaration without the "def" and final colon. Python GUIs will be
> able to do the same, thus not only giving you the function parameter
> template automatically, but also the return value template.
>
> Some disadvantages:
> - I suggest it as an addition to the current way, so there isn't any
> serious disadvantage. One person may decide to use one way, one the other.
> - Of course, if you mix the two types of function declarations in your
> software, you may need to look at the function header to see which one you
> used in the specific case.
> - You need to be aware of both ways when reading someone else's code ---
>  which is not hard, as both ways are quite easy to read.
>
> The idea at this stage of Python development may be surprising, but I hope
> that nevertheless you will consider it seriously.
> There has been a lot of experience and developlment regarding this in
> connection with Matlab,
> and I am sure that many of you know better than me how it would fit into
> Python's philosophy, and what consequences adding it may have.
>
> Thanks for your time, and best regard!
> Géza
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>
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