Declaring variables

[HMS Surprise]

I looked in the language but did not find a switch for requiring
variables to be declared before use.

Is such an option available?

Thanks,

jvh

[Grant Edwards]

On 2007-05-16, HMS Surprise <jo**@datavoiceint.comwrote:

I looked in the language but did not find a switch for requiring
variables to be declared before use.

Still trying to write Pascal, eh? ;)

Is such an option available?

No.

However, there are utilities to "proofread" your code should
you have a desire for that:

http://www.logilab.org/pylint
http://pychecker.sourceforge.net/

--
Grant Edwards grante Yow! What I need is a
at MATURE RELATIONSHIP with a
visi.com FLOPPY DISK ...

[HMS Surprise]

No haven't had to endure Pascal. Mostly C/C++, Tcl, and assembler. Oh
yeah, and a (thankfully) short stint of Ada.

But I glad to hear of the proofing tools. Working a lot of data parsed
from web pages and the developer there a different naming convention
from what I am accustomed so sometimes I introduce a new variable
unintentionally.
Thanks,

jvh

[Matimus]

On May 16, 9:57 am, HMS Surprise <[e-mail]:

I looked in the language but did not find a switch for requiring
variables to be declared before use.

Is such an option available?

Thanks,

jvh

You do have to declare a variable before use. You do so by assigning
it a value. You can't use a variable before it has been assigned. In
some ways this is less ambiguous than even C where you can declare a
variable without assigning a value. Also note that this caries the
type information, since the variable is of whatever type was assigned
to it. The only thing it doesn't do is give a unique flag that says
"hey this is where I'm declared", although I suppose you could do that
with a comment.

Matt

[Steve Holden]

Matimus wrote:

On May 16, 9:57 am, HMS Surprise <[e-mail]:

>I looked in the language but did not find a switch for requiring
variables to be declared before use.

Is such an option available?

Thanks,

jvh

You do have to declare a variable before use. You do so by assigning
it a value. You can't use a variable before it has been assigned. In
some ways this is less ambiguous than even C where you can declare a
variable without assigning a value. Also note that this caries the
type information, since the variable is of whatever type was assigned
to it. The only thing it doesn't do is give a unique flag that says
"hey this is where I'm declared", although I suppose you could do that
with a comment.

Strictly, the variable has no type at all (and strictly your "variables"
are actually names bound to values in a namespace, and it's the values
that are typed).

We shouldn't ignore the fact that declarations unambiguously say "the
programmer intends to use such-and-such a name for a value of a specific
type". Contrast this with a Python program where one path makes an
assignment (binding) to a name while another path doesn't, resulting in
a later NameError.

regards
Steve
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[HMS Surprise]

On May 16, 6:48 pm, Matimus <[e-mail]:

On May 16, 9:57 am, HMS Surprise <[e-mail]:

I looked in the language but did not find a switch for requiring
variables to be declared before use.

Is such an option available?

Thanks,

jvh

You do have to declare a variable before use. You do so by assigning
it a value. You can't use a variable before it has been assigned.

Yes this is where the problem arises. This is a gross
oversimplification , but is where I typically find problems.

jh
#~~~~~~~~~~~~~~~~~~~~~~
createdIncidentId = 0
..
..
..
#attempt to change varialbe
createdIncidentID = 1
..
..
..
if createdIncidentId == 1:
...

[Gregor Horvath]

HMS Surprise schrieb:

>
#~~~~~~~~~~~~~~~~~~~~~~
createdIncidentId = 0
.
.
.
#attempt to change varialbe
createdIncidentID = 1
.
.
.
if createdIncidentId == 1:
...

test.py is your code above

$ pychecker -v test.py
Processing test...

Warnings...

test.py:7: Variable (createdIncidentID) not used
Gregor

[Grant Edwards]

On 2007-05-16, HMS Surprise <jo**@datavoiceint.comwrote:

No haven't had to endure Pascal. Mostly C/C++, Tcl, and assembler.

I must have you mixed up with somebody else who recently
mentioned having Pascal as their first real language.

--
Grant Edwards grante Yow! It's OKAY -- I'm an
at INTELLECTUAL, too.
visi.com

[HMS Surprise]

On May 17, 9:34 am, Grant Edwards <[e-mail]:

On 2007-05-16, HMS Surprise <[e-mail]:

No haven't had to endure Pascal. Mostly C/C++, Tcl, and assembler.

I must have you mixed up with somebody else who recently
mentioned having Pascal as their first real language.

--
Grant Edwards grante Yow! It's OKAY -- I'm an
at INTELLECTUAL, too.
visi.com

That's OK. I am easily mixed up.