• Kris (13/13) Feb 12 2005 One may legitimally write the following:
• Walter (8/21) Feb 12 2005 following:
• Kris (8/34) Feb 12 2005 Hmmmm. I was trying to use it to represent an 'anonymous element', in a ...
• Walter (10/15) Feb 12 2005 length

Kris <Kris_member pathlink.com> writes:

One may legitimally write the following:

void bind (inout void[] x)
{
// ...
}

Which will match any argument of type array. But one cannot do the following:

void bind (inout void x)
{
}

which is intended to catch all non-array types.

Shouldn't this be symmetrical? The alternative is to remove the 'inout' and make
the arguments pointers instead -- not an ideal resolution.

- Kris

"Walter" <newshound digitalmars.com> writes:

"Kris" <Kris_member pathlink.com> wrote in message
news:cum3f4$2r23$1 digitaldaemon.com...
 One may legitimally write the following:

 void bind (inout void[] x)
 {
 // ...
 }

 Which will match any argument of type array. But one cannot do the

following:
 void bind (inout void x)
 {
 }

 which is intended to catch all non-array types.

 Shouldn't this be symmetrical?

The void[] is analgous to the C++ void* type, except that it adds a length
in bytes of whatever is being pointed to. void[] turns out to be a very
handy data type. It means "block of memory 'length' bytes long".

 The alternative is to remove the 'inout' and make
 the arguments pointers instead -- not an ideal resolution.

I'm not sure what use this would be. Note that although C++ (and D) have a
void* type, neither has a void& type.

Kris <Kris_member pathlink.com> writes:

In article <cumblv$31ik$1 digitaldaemon.com>, Walter says...
"Kris" <Kris_member pathlink.com> wrote in message
news:cum3f4$2r23$1 digitaldaemon.com...
 One may legitimally write the following:

 void bind (inout void[] x)
 {
 // ...
 }

 Which will match any argument of type array. But one cannot do the

following:
 void bind (inout void x)
 {
 }

 which is intended to catch all non-array types.

 Shouldn't this be symmetrical?

The void[] is analgous to the C++ void* type, except that it adds a length
in bytes of whatever is being pointed to. void[] turns out to be a very
handy data type. It means "block of memory 'length' bytes long".

Sure is!

 The alternative is to remove the 'inout' and make
 the arguments pointers instead -- not an ideal resolution.

I'm not sure what use this would be. Note that although C++ (and D) have a
void* type, neither has a void& type.

Hmmmm. I was trying to use it to represent an 'anonymous element', in a similar
manner as I've been using void[]. I can use void* instead, but it's not so nice
for the user to add the & operator. Another option is to convert the argument to
an array first, such as (&x)[0..1], and pass it as an anonymous array.

I'll futz around some more;

- Kris

"Walter" <newshound digitalmars.com> writes:

"Kris" <Kris_member pathlink.com> wrote in message
news:cumcrc$154$1 digitaldaemon.com...
 In article <cumblv$31ik$1 digitaldaemon.com>, Walter says...
The void[] is analgous to the C++ void* type, except that it adds a


length
in bytes of whatever is being pointed to. void[] turns out to be a very
handy data type. It means "block of memory 'length' bytes long".

 Sure is!

It's just a lucky epiphany I had one day struggling with byte[] being
returned from std.file.read(), very obvious in hindsight!

The other neat thing about void* in D is that one can do pointer arithmetic
on it. It's always frustrating that in C/C++ one has to cast it to char*
first, then back to void*. Dagnamit, it isn't a pointer to a char and that
shouldn't be necessary!

What you can't do with void* or void[] in D is dereference it.