TypeError: f() missing 1 required positional argument: 'x' - python-dev

The old Google Groups will be going away soon, but your browser is incompatible with the new version.
Message from discussion TypeError: f() missing 1 required positional argument: 'x'
Received-SPF: pass (google.com: domain of python-dev-bounces+dev-python+garchive-30976=googlegroups....@python.org designates 82.94.164.166 as permitted sender) client-ip=82.94.164.166;
Message-ID: <505B654A.90...@pearwood.info>
Date: Fri, 21 Sep 2012 04:49:46 +1000
From: Steven D'Aprano <st...@pearwood.info>
User-Agent: Mozilla/5.0 (X11; Linux i686;
	rv:10.0.6esrpre) Gecko/20120717 Thunderbird/10.0.6
MIME-Version: 1.0
To: python-...@python.org
References: <CAAu3qLUDriU=t+pOX9WWW5JYego1xz=0izBoh-Kg5tMivPu...@mail.gmail.com>
	<CADiSq7fERUAZNe17i=mKa7LzAyNq0yvuwTAN3FVJYG-gZHP...@mail.gmail.com>
	<CAAu3qLXHOs8G4LtxJ6q=TE5NfQ-sRquom88CzCXmzhfVK+O...@mail.gmail.com>
In-Reply-To: <CAAu3qLXHOs8G4LtxJ6q=TE5NfQ-sRquom88CzCXmzhfVK+O...@mail.gmail.com>
Subject: Re: [Python-Dev] TypeError: f() missing 1 required positional
 argument: 'x'
Precedence: list
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="us-ascii"; Format="flowed"
Errors-To: python-dev-bounces+dev-python+garchive-30976=googlegroups....@python.org
Sender: "Python-Dev"
	<python-dev-bounces+dev-python+garchive-30976=googlegroups....@python.org>

On 20/09/12 22:59, Mark Dickinson wrote:
> On Thu, Sep 20, 2012 at 1:21 PM, Nick Coghlan<ncogh...@gmail.com>  wrote:
>> +1 for using the unqualified "argument" in these error messages to
>> mean "positional or keyword argument" (inspect.Parameter spells it out
>> as POSITIONAL_OR_KEYWORD, but the full phrase is far too verbose for
>> an error message).
>
> Ah yes;  I see that 'positional or keyword' is a more accurate term
> (but agree it's unwieldy for an error message).  I also see that I was
> naive to think that the 'fix' is as simple as dropping the word
> 'positional':
>
>      >>>  def f(a, *, b):
>      ...     pass
>      ...
>      >>>  f()
>      Traceback (most recent call last):
>        File "<stdin>", line 1, in<module>
>      TypeError: f() missing 1 required positional argument: 'a'
>
> If the word 'positional' were dropped here, it would give the
> incorrect impression that f only requires one argument.


I don't expect error messages to give a complete catalog of every
problem with a specific function call. If f() reports that required
argument 'a' is missing, that does not imply that no other required
arguments are also missing. I think it is perfectly acceptable to
not report the missing 'b' until the missing 'a' is resolved.

But I do expect error messages to be accurate. +1 to remove the
word "positional" from the message.



-- 
Steven
_______________________________________________
Python-Dev mailing list
Python-...@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe: http://mail.python.org/mailman/options/python-dev/dev-python%2Bgarchive-30976%40googlegroups.com
Create a group - Google Groups - Google Home - Terms of Service - Privacy Policy
Account Options
