Re: Declaring a local dynamic variable?

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

Am 21.09.2013 13:31, schrieb Barry Margolin:
> In article <mailman.2622.1379742443.10748.help-gnu-emacs@gnu.org>,
>   Andreas Röhler <andreas.roehler@easy-emacs.de> wrote:
>
>> Am 20.09.2013 22:59, schrieb Barry Margolin:
>>> In article <mailman.2578.1379694764.10748.help-gnu-emacs@gnu.org>,
>>>    Andreas Röhler <andreas.roehler@easy-emacs.de> wrote:
>>>
>>>> Am 20.09.2013 17:10, schrieb Barry Margolin:
>>>>> In article <mailman.2569.1379688787.10748.help-gnu-emacs@gnu.org>,
>>>>>     Andreas Röhler <andreas.roehler@easy-emacs.de> wrote:
>>>>>
>>>>>> Am 20.09.2013 14:30, schrieb Stefan Monnier:
>>>>>>>> If I purposefully use a local dynamic variable as in:
>>>>>>>
>>>>>>> Use (defvar my-counter) at the file's top-level to indicate that this
>>>>>>> variable is used in a way that relies on dynamic scoping.
>>>>>>
>>>>>> A need to write code just to silence compiler warnings?
>>>>>> Emacs could do better.
>>>>>
>>>>> Other than "code", what would you suggest?
>>>>
>>>> In the precise case: just drop that warning.
>>>>
>>>> In a wider sense, IMO a modular approach is better.
>>>> Restrict compiler warnings to obvious errors, don't mix style questions in.
>>>
>>> This isn't a style warning. Often the reason is mistyping a local
>>> variable name.
>>>
>>> (let ((foobar ...))
>>>      ...
>>>      (blah fobar)
>>>      ...)
>>>
>>
>> This is another case. IIUC there was nothing wrong with the OP's example.
>
> But how is the compiler supposed to know the difference?

A code-checker might look up, if a variable is defined.
If our eyes may notice the difference, why a checker should not?

  Either it
> always warns, and generate false positives when you compile the user of
> a variable before loading the defvar, or never warns and there are false
> negatives when the user makes a typo.
>
> In this case, false positives are the better option, since you can
> easily silence them by adding a defvar. If the warning were removed,
> there's no way to get the warning when you actually do make a typo.
>

Unfortunatly it's not the only occassion. Compiler message is cluttered with false positives that way.