Steven D'Aprano wrote:
On 20/09/12 22:59, Mark Dickinson wrote:
On Thu, Sep 20, 2012 at 1:21 PM, Nick Coghlanncoghlan@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.
I disagree. There is no reason (that I'm aware of ;) that the missing 'b' cannot be noticed and reported at the same time as the missing 'a'.
But I do expect error messages to be accurate. +1 to remove the word "positional" from the message.
And then it's still not accurate as 'b' is also a required argument that is missing. Unless and until all error messages adopt your proposed 'positional argument', 'argument', 'keyword argument' *and* describe _all_ the problems with the call confusion will reign supreme.
So, ideally, the above example would be:
>>> def f(a, *, b): ... pass ... >>> f() Traceback (most recent call last): File "<stdin>", line 1, in<module> TypeError: f() missing 2 required arguments: positional: 'a', keyword: 'b'
~Ethan~
P.S. Also, a big thank-you -- the error messages *are* getting better all the time!