Declarations hiding type names

[ymuntyan@gmail.com]

Hey,

Is the following code valid:

typedef int A;
void func (void)
{
A A;
}

It looks right to me, the second "A" is a type name from
the outer scope when it's seen, so it's not hidden by the
third "A", and so that's a declaration

outer-type-A in-func-variable-A;

What makes me doubt about it is that all yacc-like
parsers I looked at will parse that line inside func() as

outer-type-A outer-type-A

[WANG Cong]

Re: Declarations hiding type names

On Fri, 14 Mar 2008 18:27:55 -0700，ymuntyan wrote：

Hey,
>
Is the following code valid:
>
typedef int A;
void func (void)
{
A A;
}
>
It looks right to me, the second "A" is a type name from the outer scope
when it's seen, so it's not hidden by the third "A", and so that's a
declaration
>
outer-type-A in-func-variable-A;

True.

A typedef name is also an identifier, and it "shares the same name space
as other identifiers declared in ordinary declarators."

Your in-func-variable-A just shadows the global-typedef-name-A.

>
What makes me doubt about it is that all yacc-like parsers I looked at
will parse that line inside func() as
>
outer-type-A outer-type-A

You should ask this question in a yacc newsgroup instead.


--
Hi, I'm a .signature virus, please copy/paste me to help me spread
all over the world.

[ymuntyan@gmail.com]

Re: Declarations hiding type names

On Mar 14, 10:45 pm, WANG Cong <xiyou.wangc... @gmail.comwrote :

On Fri, 14 Mar 2008 18:27:55 -0700$B!$(Bymu ntyan wrote$B!'(B
>

Hey,

>

Is the following code valid:

>

typedef int A;
void func (void)
{
A A;
}

>

It looks right to me, the second "A" is a type name from the outer scope
when it's seen, so it's not hidden by the third "A", and so that's a
declaration

>

outer-type-A in-func-variable-A;

>
True.
>
A typedef name is also an identifier, and it "shares the same name space
as other identifiers declared in ordinary declarators."
>
Your in-func-variable-A just shadows the global-typedef-name-A.
>
>

What makes me doubt about it is that all yacc-like parsers I looked at
will parse that line inside func() as

>

outer-type-A outer-type-A

>
You should ask this question in a yacc newsgroup instead.

Well, I figured it out. The problem was over-optimistic
people who claim that simple if-typedef-then-typename
trick will solve the typedef-name vs identifier issue.
And gcc's yacc grammar indeed has a load of stuff to
solve this issue.
Not sure why I would ask a question about C grammar in
a yacc newsgroup though ;)

Yevgen

[WANG Cong]

Re: Declarations hiding type names

On Fri, 14 Mar 2008 19:25:50 -0700，ymuntyan wrote：

What makes me doubt about it is that all yacc-like parsers I looked
at will parse that line inside func() as

>>

outer-type-A outer-type-A

>>
>You should ask this question in a yacc newsgroup instead.

>
Well, I figured it out. The problem was over-optimistic people who claim
that simple if-typedef-then-typename trick will solve the typedef-name
vs identifier issue. And gcc's yacc grammar indeed has a load of stuff
to solve this issue.
Not sure why I would ask a question about C grammar in a yacc newsgroup
though ;)
>

What you doubt about is your tool, yacc, not the C language itself. You
mentioned you know the language syntax is correct. And here only discuss
the standard C language, neither its extensions nor any implementions.

I think gnu.gcc.help will be much more appropriate to discuss your
problem, or any other yacc groups which I don't know.

--
Hi, I'm a .signature virus, please copy/paste me to help me spread
all over the world.

[Kenny McCormack]

Re: Declarations hiding type names

In article <frg2lm$d8c$1@n ews.cn99.com>,
WANG Cong <xiyou.wangcong @gmail.comtedio usly scribed (as if the
point hadn't been made 50,000,000 times over the past 15 years):
....

>What you doubt about is your tool, yacc, not the C language itself. You
>mentioned you know the language syntax is correct. And here only discuss
>the standard C language, neither its extensions nor any implementions.

Tedious.