array subscript type cannot be `char`?

[Michael Mair]

Re: array subscript type cannot be `char`?

Jordan Abel schrieb:[color=blue]
> On 2006-03-27, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>[color=green]
>>Jordan Abel schrieb:
>>[color=darkred]
>>>Note: No context quoted because I'm replying to the actual issue the
>>>thread brings up rather than to any particular post
>>>
>>>What all this is missing is that it's silly to warn on an array
>>>subscript of type char when you don't warn on one of type signed int.
>>>
>>>Idea -- magic safe macro for isalpha:
>>>
>>>#define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))[/color]
>>
>>Hmmm. Nice until x is something with sideeffects like, say,
>>"c = getchar()".[/color]
>
> That's why it's uppercase. To warn you.[/color]

For functionality as basic as this, I do not trust anyone
to use it consistently correctly -- including me. I remember
a then-colleague abusing a macro with the words "Oh, it's
from XY -- he surely did something clever"... ;-(

Cheers
Michael
--
E-Mail: Mine is an /at/ gmx /dot/ de address.

[Jordan Abel]

Re: array subscript type cannot be `char`?

On 2006-03-28, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:[color=blue]
> Jordan Abel schrieb:[color=green]
>> On 2006-03-27, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>>[color=darkred]
>>>Jordan Abel schrieb:
>>>
>>>>Note: No context quoted because I'm replying to the actual issue the
>>>>thread brings up rather than to any particular post
>>>>
>>>>What all this is missing is that it's silly to warn on an array
>>>>subscript of type char when you don't warn on one of type signed int.
>>>>
>>>>Idea -- magic safe macro for isalpha:
>>>>
>>>>#define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))
>>>
>>>Hmmm. Nice until x is something with sideeffects like, say,
>>>"c = getchar()".[/color]
>>
>> That's why it's uppercase. To warn you.[/color]
>
> For functionality as basic as this, I do not trust anyone
> to use it consistently correctly -- including me. I remember
> a then-colleague abusing a macro with the words "Oh, it's
> from XY -- he surely did something clever"... ;-([/color]

as it turns out, i _did_ do something clever. x is evaluated only once.

--
look closer...

[pete]

Re: array subscript type cannot be `char`?

Jordan Abel wrote:[color=blue]
>
> Note: No context quoted because I'm replying to the actual issue the
> thread brings up rather than to any particular post
>
> What all this is missing is that it's silly to warn on an array
> subscript of type char when you don't warn on one of type signed int.
>
> Idea -- magic safe macro for isalpha:
>
> #define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))[/color]

I don't understand what that macro is for, or how you would use it.
If you would cast a byte sized type to unsigned char,
why wouldn't you cast a larger type to unsigned char?

--
pete

[CBFalconer]

Re: array subscript type cannot be `char`?

Jordan Abel wrote:[color=blue]
> On 2006-03-28, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:[color=green]
>> Jordan Abel schrieb:[color=darkred]
>>> On 2006-03-27, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>>>> Jordan Abel schrieb:
>>>>
>>>>> Note: No context quoted because I'm replying to the actual
>>>>> issue the thread brings up rather than to any particular post
>>>>>
>>>>> What all this is missing is that it's silly to warn on an
>>>>> array subscript of type char when you don't warn on one of type
>>>>> signed int.
>>>>>
>>>>> Idea -- magic safe macro for isalpha:
>>>>>
>>>>> #define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))
>>>>
>>>> Hmmm. Nice until x is something with sideeffects like, say,
>>>> "c = getchar()".
>>>
>>> That's why it's uppercase. To warn you.[/color]
>>
>> For functionality as basic as this, I do not trust anyone
>> to use it consistently correctly -- including me. I remember
>> a then-colleague abusing a macro with the words "Oh, it's
>> from XY -- he surely did something clever"... ;-([/color]
>
> as it turns out, i _did_ do something clever. x is evaluated
> only once.[/color]

There you go - somebody finally noticed.

--
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the broken "Reply" link at the bottom of the article. Click on
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"Reply" at the bottom of the article headers." - Keith Thompson
More details at: <http://cfaj.freeshell. org/google/>
Also see <http://www.safalra.com/special/googlegroupsrep ly/>

[Jordan Abel]

Re: array subscript type cannot be `char`?

On 2006-03-28, pete <pfilandr@minds pring.com> wrote:[color=blue]
> Jordan Abel wrote:[color=green]
>>
>> Note: No context quoted because I'm replying to the actual issue the
>> thread brings up rather than to any particular post
>>
>> What all this is missing is that it's silly to warn on an array
>> subscript of type char when you don't warn on one of type signed int.
>>
>> Idea -- magic safe macro for isalpha:
>>
>> #define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))[/color]
>
> I don't understand what that macro is for, or how you would use it.
> If you would cast a byte sized type to unsigned char,
> why wouldn't you cast a larger type to unsigned char?[/color]

Because the larger type is likely to be an int which is safe to use
since it will be valued either EOF or between 0 and UCHAR_MAX [e.g. the
result from getc] the issue is that a char value could be a negative
number other than EOF.

[Michael Mair]

Re: array subscript type cannot be `char`?

Jordan Abel schrieb:[color=blue]
> On 2006-03-28, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>[color=green]
>>Jordan Abel schrieb:
>>[color=darkred]
>>>On 2006-03-27, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>>>
>>>
>>>>Jordan Abel schrieb:
>>>>
>>>>
>>>>>Note: No context quoted because I'm replying to the actual issue the
>>>>>thread brings up rather than to any particular post
>>>>>
>>>>>What all this is missing is that it's silly to warn on an array
>>>>>subscrip t of type char when you don't warn on one of type signed int.
>>>>>
>>>>>Idea -- magic safe macro for isalpha:
>>>>>
>>>>>#define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))
>>>>
>>>>Hmmm. Nice until x is something with sideeffects like, say,
>>>>"c = getchar()".
>>>
>>>That's why it's uppercase. To warn you.[/color]
>>
>>For functionality as basic as this, I do not trust anyone
>>to use it consistently correctly -- including me. I remember
>>a then-colleague abusing a macro with the words "Oh, it's
>>from XY -- he surely did something clever"... ;-([/color]
>
> as it turns out, i _did_ do something clever. x is evaluated only once.[/color]

You are right -- my bad.

Cheers
Michael
--
E-Mail: Mine is an /at/ gmx /dot/ de address.

[Jordan Abel]

Re: array subscript type cannot be `char`?

On 2006-03-28, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:[color=blue]
> Jordan Abel schrieb:[color=green]
>> On 2006-03-28, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>>[color=darkred]
>>>Jordan Abel schrieb:
>>>
>>>>On 2006-03-27, Michael Mair <Michael.Mair@i nvalid.invalid> wrote:
>>>>
>>>>
>>>>>Jordan Abel schrieb:
>>>>>
>>>>>
>>>>>>Note: No context quoted because I'm replying to the actual issue the
>>>>>>thread brings up rather than to any particular post
>>>>>>
>>>>>>What all this is missing is that it's silly to warn on an array
>>>>>>subscri pt of type char when you don't warn on one of type signed int.
>>>>>>
>>>>>>Idea -- magic safe macro for isalpha:
>>>>>>
>>>>>>#define ISALPHA(x) isalpha(sizeof( x)==1?(unsigned char)(x):(x))
>>>>>
>>>>>Hmmm. Nice until x is something with sideeffects like, say,
>>>>>"c = getchar()".
>>>>
>>>>That's why it's uppercase. To warn you.
>>>
>>>For functionality as basic as this, I do not trust anyone
>>>to use it consistently correctly -- including me. I remember
>>>a then-colleague abusing a macro with the words "Oh, it's
>>>from XY -- he surely did something clever"... ;-([/color]
>>
>> as it turns out, i _did_ do something clever. x is evaluated only once.[/color]
>
> You are right -- my bad.[/color]

I didn't realize it at first either, it's easy to miss.