Macro parameter list

[Jack Morgan]

I got a macro like this in my code.

#define DECLARE_SOMEWND STRUCTURE(style , nums, clrref, icon, tablenum,
name,
menuname)\
static SOMEWNDSTRUCT &GetSomeWndStru ct()\
{\
static SOMEWNDSTRUCT somestruct = {\
style, bits, clrref, icon, tablenum, name, menuname};\
return somestruct ;\
} And I want to be able to do something like this
Have a generic paremeter list...
GENERIC 1,2,3,4,5,6,7
GENERICNAME(nam e) 1,2,3,4,5,name, 7 Which then could be used like this.
DECLARE_SOMEWND STRUCTURE(GENER IC)
DECLARE_SOMEWND STRUCTURE(GENER ICNAME("Jimbo") )

Obviously this doesn't work - warning C4003: not enough actual
parameters for macro...So could anybody explain how something like this
is done?

[ais523]

Jack Morgan wrote:

I got a macro like this in my code.

#define DECLARE_SOMEWND STRUCTURE(style , nums, clrref, icon, tablenum,
name,
menuname)\
static SOMEWNDSTRUCT &GetSomeWndStru ct()\
{\
static SOMEWNDSTRUCT somestruct = {\
style, bits, clrref, icon, tablenum, name, menuname};\
return somestruct ;\
}

And I want to be able to do something like this
Have a generic paremeter list...
GENERIC 1,2,3,4,5,6,7
GENERICNAME(nam e) 1,2,3,4,5,name, 7

Which then could be used like this.
DECLARE_SOMEWND STRUCTURE(GENER IC)
DECLARE_SOMEWND STRUCTURE(GENER ICNAME("Jimbo") )

Obviously this doesn't work - warning C4003: not enough actual
parameters for macro...So could anybody explain how something like this
is done?

Here's an example of how to do it (with some trivial test code; this
has been tested):

#define PRINT3D(a,b,c) do {printf("%d%d%d \n",a,b,c);} while(0)
#define MACROCALL(x,y) x(y)
#define P3DARGS 1,2,3

#include <stdio.h>

int main(void)
{
MACROCALL(PRINT 3D,P3DARGS);
return 0;
}

In many preprocessor problems, an extra level of macro expansion is all
that is needed. This shouldn't be too hard to adapt to your code.

[Alf P. Steinbach]

* Jack Morgan:

I got a macro like this in my code.
#define DECLARE_SOMEWND STRUCTURE(style , nums, clrref, icon, tablenum,
name,
menuname)\
static SOMEWNDSTRUCT &GetSomeWndStru ct()\
{\
static SOMEWNDSTRUCT somestruct = {\
style, bits, clrref, icon, tablenum, name, menuname};\
return somestruct ;\
}
And I want to be able to do something like this
Have a generic paremeter list...
GENERIC 1,2,3,4,5,6,7
GENERICNAME(nam e) 1,2,3,4,5,name, 7
Which then could be used like this.
DECLARE_SOMEWND STRUCTURE(GENER IC)
DECLARE_SOMEWND STRUCTURE(GENER ICNAME("Jimbo") )
Obviously this doesn't work - warning C4003: not enough actual
parameters for macro...So could anybody explain how something like this
is done?

How about

#define DECLARE_NAMED(n ame) DECLARE_SOMEWND STRUCTURE(1,2,3 ,4,5,name,7)
#define DECLARE_DEFAULT DECLARE_NAMED( 6 )

But I guess this macro evilness is just a symptom of something more
sinister.

Technically you're trying to invent default macro arguments in order to
solve some problem. It's difficult to see what that problem is. But
let's say (correct me if I'm wrong) that the problem is

* How to provide default values for most values in a collection.

And one way to do that is to copy a default collection and simply change
the value or values that should not default, e.g.

ValueCollection defaultValues() { ... }

ValueCollection valuesWithName( std::string const& aName )
{
ValueCollection result = defaultValues() ;
result.name = aName;
return result;
}

Or it could be an override of a virtual function, like

ValueCollection Base::values() const { ... }

std::string Derived::name() const { return "abra kadabra"; }

ValueCollection Derived::values () const
{
ValueCollection result = Base::values();
result.name = name();
return result;
}

You could even go so far as to use one virtual function per value.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[John Vielerki]

Your code generates a error C4003: not enough actual parameters for
macro 'PRINT3D'

[Keith Thompson]

"John Vielerki" <me*********@ya hoo.com> writes:

Your code generates a error C4003: not enough actual parameters for
macro 'PRINT3D'

What code?

Read <http://cfaj.freeshell. org/google/> to understand why your post
made no sense, and how to fix it next time.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[John Vielerki]

Sry, I sometimes forget that not everyone uses Google :( Here you go.:

I got a macro like this in my code.

#define DECLARE_SOMEWND STRUCTURE(style , nums, clrref, icon, tablenum,
name,
menuname)\
static SOMEWNDSTRUCT &GetSomeWndStru ct()\
{\
static SOMEWNDSTRUCT somestruct = {\
style, bits, clrref, icon, tablenum, name, menuname};\
return somestruct ;\
}

And I want to be able to do something like this
Have a generic paremeter list...
GENERIC 1,2,3,4,5,6,7
GENERICNAME(nam e) 1,2,3,4,5,name, 7

Which then could be used like this.
DECLARE_SOMEWND STRUCTURE(GENER IC)
DECLARE_SOMEWND STRUCTURE(GENER ICNAME("Jimbo") )

Obviously this doesn't work - warning C4003: not enough actual
parameters for macro...So could anybody explain how something like this
is done?

Here's an example of how to do it (with some trivial test code; this
has been tested):

#define PRINT3D(a,b,c) do {printf("%d%d%d \n",a,b,c);} while(0)
#define MACROCALL(x,y) x(y)
#define P3DARGS 1,2,3

#include <stdio.h>

int main(void)
{
MACROCALL(PRINT 3D,P3DARGS);
return 0;
}

In many preprocessor problems, an extra level of macro expansion is all
that is needed. This shouldn't be too hard to adapt to your code.

Your code generates a error C4003: not enough actual parameters for
macro 'PRINT3D'

[Mark McIntyre]

On 23 Mar 2006 15:09:03 -0800, in comp.lang.c , "John Vielerki"
<me*********@ya hoo.com> wrote:

Sry, I sometimes forget that not everyone uses Google :(

Scary, given that in fact its more to the point that hardly anyone
uses google...

please also see:

<http://cfaj.freeshell. org/google/>

[Keith Thompson]

"John Vielerki" <me*********@ya hoo.com> writes:

Sry, I sometimes forget that not everyone uses Google :( Here you go.:

[ followup with context snipped ]

Thanks! But pleae don't snip the attribution lines; it can be helpful
to know who wrote what.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Keith Thompson]

Mark McIntyre <ma**********@s pamcop.net> writes:

On 23 Mar 2006 15:09:03 -0800, in comp.lang.c , "John Vielerki"
<me*********@ya hoo.com> wrote:

Sry, I sometimes forget that not everyone uses Google :(
Scary, given that in fact its more to the point that hardly anyone
uses google...

Alas, that's not the case.
please also see:

<http://cfaj.freeshell. org/google/>

He already did.

--
Keith Thompson (The_Other_Keit h) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
We must do something. This is something. Therefore, we must do this.

[Mark McIntyre]

On Fri, 24 Mar 2006 00:24:11 GMT, in comp.lang.c , Keith Thompson
<ks***@mib.or g> wrote:

Mark McIntyre <ma**********@s pamcop.net> writes:

On 23 Mar 2006 15:09:03 -0800, in comp.lang.c , "John Vielerki"
<me*********@ya hoo.com> wrote:

Sry, I sometimes forget that not everyone uses Google :(

Scary, given that in fact its more to the point that hardly anyone
uses google...

Alas, that's not the case.

There's around eight billion people in the world., I sincerely doubt
that most of them use google.

Mark McIntyre
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it."
--Brian Kernighan