Adding the ability to add functions into structures?

[Albert]

So structures are useful to group variables, so you can to refer to a
collection as a single entity. Wouldn't it be useful to also have the
ability to collect variable and functions?

Ask K&R say, C programs consist of variables to store the input and
functions to manipulate them.

This would make C object-oriented - how cool would that be?

Are there any problems with adding the ability to have functions
encapsulated in structures?

[Chuck F.]

Richard Heathfield wrote:

Chuck F. said:

Jack Klein wrote:

... snip ...

I know I'll get flamed for this, but with the exception of
inheritance this is really nothing but syntactical sugar.
You can write object oriented programs in C right now.

A perfect example is the FILE data type, declared an
<stdio.h>. It has a creator, fopen(), a destructor,
fclose(), and all sorts of methods you can invoke on it via
its pointer, such as fprintf(), fscanf(), fread(), fwrite(),
between its successful creation and its destruction.

I see no reason for any fires. The only problem with your
example is that you can't write (in general) that type in C.

I must have misunderstood what you mean, because I see no reason
whatsoever why one could not write (in general) that type in C.

I meant that to implement FILE you have to access such things as
ports, disks, etc. that take you out of pure C.

--
"If you want to post a followup via groups.google.c om, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
More details at: <http://cfaj.freeshell. org/google/>

[Eric Sosman]

jacob navia wrote:

[...]
For instance:

1) I define a forward declaration to the object
typedef struct _ArrayList ArrayList;

Have you forgotten that the identifier `_ArrayList'
is off-limits?

"All identifiers that begin with an underscore and
either an uppercase letter or another underscore
are always reserved for any use."
-- ISO/IEC 9899:1999 section 7.1.3 paragraph 1

--
Eric Sosman
es*****@acm-dot-org.invalid

[Richard Heathfield]

Chuck F. said:

Richard Heathfield wrote:

Chuck F. said:

The only problem with your
example is that you can't write (in general) that type in C.

I must have misunderstood what you mean, because I see no reason
whatsoever why one could not write (in general) that type in C.

I meant that to implement FILE you have to access such things as
ports, disks, etc. that take you out of pure C.

Oh. I thought you meant opaque types were impossible, which they clearly
aren't.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at above domain (but drop the www, obviously)

[Eric Sosman]

jacob navia wrote:

[...]
2) I define the interface functions:
typedef struct {
// Returns the number of elements stored
int (*GetCount)(Arr ayList &AL);

Whatever this language is, I doubt it's topical on
comp.lang.c.

--
Eric Sosman
es*****@acm-dot-org.invalid

[jacob navia]

Eric Sosman a écrit :

jacob navia wrote:

[...]
2) I define the interface functions:
typedef struct {
// Returns the number of elements stored
int (*GetCount)(Arr ayList &AL);

Whatever this language is, I doubt it's topical on
comp.lang.c.

Yes, replace the "&" by "*".
lcc-win32 supports "&" as in C++, but it can be
replaced by "*". References are just pointers that
can never be NULL. A pointer will do too.

[jacob navia]

Eric Sosman a écrit :

jacob navia wrote:

[...]
For instance:

1) I define a forward declaration to the object
typedef struct _ArrayList ArrayList;

Have you forgotten that the identifier `_ArrayList'
is off-limits?

"All identifiers that begin with an underscore and
either an uppercase letter or another underscore
are always reserved for any use."
-- ISO/IEC 9899:1999 section 7.1.3 paragraph 1

Yes, you are right. Just put
typedef struct tagArrayList

Sometimes I use _ because is shorter

[Chuck F.]

Eric Sosman wrote:

jacob navia wrote:

[...]
For instance:

1) I define a forward declaration to the object
typedef struct _ArrayList ArrayList;

Have you forgotten that the identifier `_ArrayList'
is off-limits?

"All identifiers that begin with an underscore and
either an uppercase letter or another underscore
are always reserved for any use."
-- ISO/IEC 9899:1999 section 7.1.3 paragraph 1

In this case I think you have forgotten that Jacob is the
implementor, and thus correctly avoiding the users namespace.

--
"If you want to post a followup via groups.google.c om, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
More details at: <http://cfaj.freeshell. org/google/>

[Clark S. Cox III]

On 2005-12-31 09:50:09 -0500, jacob navia <ja***@jacob.re mcomp.fr> said:

Eric Sosman a écrit :

jacob navia wrote:

[...]
2) I define the interface functions:
typedef struct {
// Returns the number of elements stored
int (*GetCount)(Arr ayList &AL);

Whatever this language is, I doubt it's topical on
comp.lang.c.

Yes, replace the "&" by "*".
lcc-win32 supports "&" as in C++, but it can be
replaced by "*". References are just pointers that
can never be NULL. A pointer will do too.

Why do you keep posting code that, while almost C, will only work on a
single compiler, on a single platform?

--
Clark S. Cox, III
cl*******@gmail .com

[Keith Thompson]

jacob navia <ja***@jacob.re mcomp.fr> writes:

Eric Sosman a écrit :

jacob navia wrote:

[...]
For instance:

1) I define a forward declaration to the object
typedef struct _ArrayList ArrayList;

Have you forgotten that the identifier `_ArrayList'
is off-limits?
"All identifiers that begin with an underscore and
either an uppercase letter or another underscore
are always reserved for any use."
-- ISO/IEC 9899:1999 section 7.1.3 paragraph 1

Yes, you are right. Just put
typedef struct tagArrayList

Sometimes I use _ because is shorter

Why not just use

struct ArrayList {
...
};

and then consistently refer to the type as "struct ArrayList"? What
benefit does the typedef give you? (If you think not having to type
the word "struct" is enough of a benefit, I disagree but I won't argue
about it.)

--
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.

[jacob navia]

Clark S. Cox III a écrit :

On 2005-12-31 09:50:09 -0500, jacob navia <ja***@jacob.re mcomp.fr> said:

Eric Sosman a écrit :

jacob navia wrote:

[...]
2) I define the interface functions:
typedef struct {
// Returns the number of elements stored
int (*GetCount)(Arr ayList &AL);

Whatever this language is, I doubt it's topical on
comp.lang.c.

Yes, replace the "&" by "*".
lcc-win32 supports "&" as in C++, but it can be
replaced by "*". References are just pointers that
can never be NULL. A pointer will do too.

Why do you keep posting code that, while almost C, will only work on a
single compiler, on a single platform?

Well, I forgot that. It is a single compiler yes, and I do not have
the means of porting it. But what's your point?

Changing "&" by "*" will make it work in any compiler in any platform.