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reference/alias in perl vs reference/alias in C++

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reference/alias in perl vs reference/alias in C++ grocery_stocker 05-23-2008
Posted by grocery_stocker on May 23, 2008, 1:48 pm
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How are references and aliases in perl different than references in
aliases in C++?

Posted by Jim Gibson on May 23, 2008, 3:22 pm
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In article

> How are references and aliases in perl different than references in
> aliases in C++?

Some differences (not exhaustive):

Aliases in Perl are like references in C++: a different way of
accessing the same object.

References in Perl are like pointers in C/C++: indirect access to an
object. However, in Perl you cannot do arithmetic on references the way
you can for C/C++ pointers (e.g. *(p++) = getchar();)

In Perl, references are scalars, not separate pointer types as in C/C++.

In C/C++, arrays are really pointers to the first element in a
contiguous set of elements. In Perl, arrays are separate objects. A
reference to an array in Perl is different than a reference to one of
the members of the array.

--
Jim Gibson

Posted by grocery_stocker on May 23, 2008, 3:41 pm
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> In article
>
> > How are references and aliases in perl different than references in
> > aliases in C++?
>
> Some differences (not exhaustive):
>
> Aliases in Perl are like references in C++: a different way of
> accessing the same object.
>
> References in Perl are like pointers in C/C++: indirect access to an
> object. However, in Perl you cannot do arithmetic on references the way
> you can for C/C++ pointers (e.g. *(p++) = getchar();)
>
> In Perl, references are scalars, not separate pointer types as in C/C++.
>
> In C/C++, arrays are really pointers to the first element in a
> contiguous set of elements. In Perl, arrays are separate objects. A
> reference to an array in Perl is different than a reference to one of
> the members of the array.
>
> --
> Jim Gibson

Everytime I ask a question on the newsgroup, i keep on thinking "I'm
sure things would have been a lot easier if I would have taken more
than 6 week of FORTRAN." I don't care what anyone says. Learning to
program on your own. mastering the core concepts without formal
schooling, and then actually making it as a programmer takes a certain
level of skill and internal drive. Not everyone has it.

I think I only know a few people with no more than a high school
education that are doing the same kind of work, for the exact same
pay, as a person with an advanced degree in the sciences.

Posted by Jürgen Exner on May 23, 2008, 3:59 pm
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>> > How are references and aliases in perl different than references in
>> > aliases in C++?

>> References in Perl are like pointers in C/C++: indirect access to an
>> object. However, in Perl you cannot do arithmetic on references the way
>> you can for C/C++ pointers (e.g. *(p++) = getchar();)

Another very major difference: in C pointers are just (virtual) memory
addresses and the programmer is forced to implement his own memory
management for objects that are addressed by pointers.
In Perl any memory management for objects referred to by references is
done automatically by the system.

jue

Posted by A. Sinan Unur on May 23, 2008, 6:44 pm
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>> In article
>>
>> > How are references and aliases in perl different than references in
>> > aliases in C++?
>>

[ snip Jim's explanation ]

>> --
>> Jim Gibson

[ Do *NOT* quote sigs ]

> Everytime I ask a question on the newsgroup, i keep on thinking "I'm
> sure things would have been a lot easier if I would have taken more
> than 6 week of FORTRAN."

I did do some FORTRAN programming almost 20 years ago. I am not sure
what you are getting at though.

> I don't care what anyone says.

Well, I am reminded of

http://www.catb.org/~esr/faqs/hacker-howto.html#believe5

> Learning to program on your own.

http://en.wikipedia.org/wiki/Sentence_%28linguistics%29

> mastering the core concepts without formal
> schooling, and then actually making it as a programmer takes a certain
> level of skill and internal drive.

Are you referring to yourself here?

I am not sure what "making it as a programmer" means above. On the other
hand, almost everyday at work is an opportunity for me to run into
someone who thinks he/she has made it as a programmer. I am not sure I
agree with those people's self-assessments.

> Not everyone has it.

True.

> I think I only know a few people with no more than a high school
> education that are doing the same kind of work, for the exact same
> pay, as a person with an advanced degree in the sciences.

The only thing that shows me is that the person with the advanced degree
in the sciences has chosen not to work in the field in which he/she
earned the degree.

Clearly, once one has a certain mental capability, whether one chooses
to invest time in an advanced degree is a matter of preference. Another
person with even superior mental capacity may choose not to "waste" five
to seven years toiling on a project which is of interest to only a few
people and which, as a norm, do not generate huge monetary returns on
that investment. This is why I do not put much stock in letters before
or after a person's name.

Achieving that goal also takes a certain level of skill and drive.

If I were you, I would not be so quick to pat myself on the back for
this particular reason until I were able to compete with Physics Ph.D.'s
in the fields in which they earned their degrees.

You can be proud of your achievements without resorting to this silly
argument.

Switching back to discussing Perl ... now.

Sinan

--
(remove .invalid and reverse each component for email address)

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