Vincent Lefevre <[EMAIL PROTECTED]> writes:
> On 2008-02-08 16:04:40 +0100, Wolfram Fenske wrote:
>> Oliver Kiddle <[EMAIL PROTECTED]> writes:
>>
>> > The following is a bug reported for the Debian ksh package. Thanks
>>
>> [...]
>>
>> > According to POSIX[*], "test \( ! -e \)" is a 4-argument test and is
>> > here equivalent to "test ! -e".
>>
>> Where specifically does the POSIX standard say that?
>
> This was in the forwarded message you replied to:
>
> http://www.opengroup.org/onlinepubs/009695399/utilities/test.html
I did notice that. See, when I said "specifically" I didn't mean
"Quote me a document with a couple hundred lines of text -- again."
But never mind, I think I found the passage you were referring to:
--8<---------------cut here---------------start------------->8---
The algorithm for determining the precedence of the operators and the
return value that shall be generated is based on the number of
arguments presented to test. [...]
In the following list, $1, $2, $3, and $4 represent the arguments
presented to test:
[...]
* 2 arguments:
* If $1 is '!', exit true if $2 is null, false if $2 is not null.
* If $1 is a unary primary, exit true if the unary test is true,
false if the unary test is false.
* Otherwise, produce unspecified results.
[...]
* 4 arguments:
* If $1 is '!', negate the three-argument test of $2, $3, and $4.
* [XSI] [Option Start] If $1 is '(' and $4 is ')', perform the
two-argument test of $2 and $3. [Option End]
* Otherwise, the results are unspecified.
--8<---------------cut here---------------end--------------->8---
>> I read
>>
>> $ test \( ! -e \)
>>
>> as an instance of "( expression )".
>
> Yes, where expression is a 2-argument test.
>
>> However, the expresion is malformed because "-e" does not have an
>> argument.
>
> No, it is equivalent to the 2-argument test:
>
> test ! -e
>
> where -e is just a string. See
>
> http://www.opengroup.org/onlinepubs/009695399/utilities/test.html
>
>> The Gnu test's solution of treating "test \( ! -e \);" as "test !
>> -e;" may be nice, but it requires the parser to be *very*
>> forgiving, which IMO is not always a good thing.
>
> No, the parser just needs to follow the POSIX specification, which
> is quite clear here.
You're right. I jumped to conclusions by assuming "-e" was used as a
primary, but it's actually used as a plain string, making the test
case equivalent to
test \( ! foo \)
--
Wolfram Fenske
A: Yes.
>Q: Are you sure?
>>A: Because it reverses the logical flow of conversation.
>>>Q: Why is top posting frowned upon?
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