Q:ADA/Java/C++ feature mapping question!?

Q:ADA/Java/C++ feature mapping question!?

[alex]

Hi,
my question should be easy to answer for anyone who knows C++/Java and ADA.
Unfortunately I only know C++&Java :-(.

Question: What are the corresponding ADA keywords to the given C++/Java
features, and which keywords do exist in ADA which have no representation in
C++/Java, and what do they mean. I did have a look at the
http://www.adahome.com/rm95/ Ada reference Manual, but this would be a
longer way to go then I would like to. So could one of you who knows both
languages help me out?


C++/Java Keywords of interest to me:

auto:      variable has local (automatic) extent

abstract  (Java)  pure virtual

const:    functions values are not modifiable

explicit:    Constructors declared explicit will not be considered for
implicit conversions

extern:    Variable or function has external linkage, or linkage conversion
of another language

final    (Java) class, method cannot be derived from or overwritten

friend:     function or class has access to private/protected class members

interface    (Java)  concept for abstract interface suitable for multiple
inheritance

mutable:    Non-static non const data members. If declared mutable it is
legal to assign a value to this data member from a const member function

native  (Java) modifier used in the declaration of a method to indicate that
the method is implemented in another programming language

namespace:    obvious

package  (Java) obvious

private:     visibility for class member

protected:     visibility for class member

public:    visibility for class member

register:    "asks" compiler to place variable in CPU register

synchronized  (Java) modifier to specify thread-safe methods

static:    linkage for variables and functions

template:    set of parameterized classes or functions

virtual:    polymorphism for functions, for classes to disable multiple
members while using multiple inheritance

transient  (Java) modifier used in the declaration of variables

volatile:    type qualifier; object can be modified in the program by
something other than statements, such as the operating system, the hardware,
or a concurrently executing thread

Thank you very much in advance for any help!

cu,
alex

Re: Q:ADA/Java/C++ feature mapping question!?

[Vladimir Olensky]

alex wrote in message <8672ec$e28$1@fleetstreet.Austria.EU.net>...
>Hi,
>my question should be easy to answer for anyone who knows C++/Java and ADA.
>Unfortunately I only know C++&Java :-(.
>
>Question: What are the corresponding ADA keywords to the given C++/Java
>features, and which keywords do exist in ADA which have no representation
in
>C++/Java, and what do they mean. I did have a look at the
>http://www.adahome.com/rm95/ Ada reference Manual, but this would be a
>longer way to go then I would like to. So could one of you who knows both
>languages help me out?


1. Have a look at  "A Comparison of the Object-Oriented Features of Ada 95
and Java" by Benjamin M. Brosgol  from Aonix.
This paper is located at the http://www.adaic.com/docs/reports/

2. At http://www.acm.org/sigs/sigada/conf/sa98/papers/ you will find another
interesting paper written by the same author : "A Comparison of the
Concurrency Features of Ada 95 and Java" .

3. "Ada-95: A guide for C and C++ programmers" at
http://www.adahome.com/Ammo/cpp2ada.html  also may be useful for you.

Hope that in these articles you will find answers to most of your questions.

At first two pages there are many very interesting articles and reports as
well.

Regards,
Vladimir Olensky

Re: Q:ADA/Java/C++ feature mapping question!?

[Jim Rogers]

In article <8672ec$e28$1@fleetstreet.Austria.EU.net>,
  "alex" <nulldevice@hotmail.com> wrote:
> Hi,
> my question should be easy to answer for anyone who knows C++/Java
and ADA.
> Unfortunately I only know C++&Java :-(.
>
> Question: What are the corresponding ADA keywords to the given
C++/Java
> features, and which keywords do exist in ADA which have no
representation in
> C++/Java, and what do they mean.

You can also look into a work produced by Simon Johnston comparing
the syntax features of Ada and C++. This work is available in two
forms. The more complete form is a book that should be available on
Amazon.Com, and an HTML document available from www.adahome.com.
The WEB version was written in 1995, so it has not been changed
to keep up with changes in the C++ standard. It should be a good
starting point to answer your questions.

The web page is titled: Ada-95: A guide for C and C++ programmers



--
Jim Rogers
Colorado Springs, Colorado USA


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Re: Q:ADA/Java/C++ feature mapping question!?

[Tucker Taft]

alex wrote:
> 
> Hi,
> my question should be easy to answer for anyone who knows C++/Java and ADA.
> Unfortunately I only know C++&Java :-(.
> 
> Question: What are the corresponding ADA keywords to the given C++/Java
> features, and which keywords do exist in ADA which have no representation in
> C++/Java, and what do they mean. I did have a look at the
> http://www.adahome.com/rm95/ Ada reference Manual, but this would be a
> longer way to go then I would like to. So could one of you who knows both
> languages help me out?
> 
> C++/Java Keywords of interest to me:
> 
> auto:      variable has local (automatic) extent

This is the default in Ada, as it is in C.  In fact, in Ada,
*all* local variables have "local" extent.  It is generally a rule
in Ada that the lifetime of an object is determined by where it
is declared, not by any keyword like "static" or "own" as in some languages.
If you want something to "live" longer, you need to move its declaration
out to a scope which lives longer (e.g. an enclosing package).

> abstract  (Java)  pure virtual

abstract.

> const:    functions values are not modifiable

"constant" for declared objects, and "in" for parameters

> explicit:    Constructors declared explicit will not be considered for
> implicit conversions

Ada has very few implicit conversions, generally only from numeric literals
to specific numeric types.  There are no implicit conversions based
on single-parameter constructors, as in C++.

> 
> extern:    Variable or function has external linkage, or linkage conversion
> of another language

Variables/subprograms declared in the "public" or "visible" part of a package
are accessible internally.  Note that because of inlines and generics,
entities declared in the private part or body of a package may still end
up with "extern" linkage, but this is a low-level issue.

The equivalent of C++'s 'extern "C" { ... }' are the pragmas
Import/Export/Convention (see the section on "interfacing pragmas" in
Annex B of the reference manual).

> 
> final    (Java) class, method cannot be derived from or overwritten

Any operation that is not a "primitive" operation of a type cannot be
overridden (nor is it inherited).  Any type that is not "tagged"
cannot be extended, though you can still "derive" from it without
extending.

> 
> friend:     function or class has access to private/protected class members

Child packages are similar to friends, in that they have additional
visibility onto the private declarations of their ancestor packages.

> 
> interface    (Java)  concept for abstract interface suitable for multiple
> inheritance

Generic signatures are about the closest thing in Ada 95.  A generic
signature is a generic package declaration with only a formal part,
and no declarations in the visible part.  They are useful in combination
with formal package parameters.

You can also use access discriminants and generic mixins to solve the
same kinds of problems solved by multiple inheritance.
> 
> mutable:    Non-static non const data members. If declared mutable it is
> legal to assign a value to this data member from a const member function

A "const" member function is one whose "controlling operand" is of
mode "in."  There is no notion of a "mutable" component of an "in"
object.  However, you can accomplish this by using a level of indirection.
The component would be accessed via an access-to-variable component.
The component itself might be allocated in the heap, or as an "aliased"
part of the enclosing record.
> 
> native  (Java) modifier used in the declaration of a method to indicate that
> the method is implemented in another programming language

pragma Import

> 
> namespace:    obvious

package (roughly -- C++ namespaces don't provide any visibility control)

> 
> package  (Java) obvious

package (though in Ada, the hierarchical package namespace is relevant
to visibility, whereas in Java "sub" packages have no different visibility
on their "enclosing" package than any other unrelated package.

> 
> private:     visibility for class member

declared in package body

> 
> protected:     visibility for class member

declared in private part of package spec, making it visible to child
packages.

> 
> public:    visibility for class member

Declared in visible part of package spec.

> 
> register:    "asks" compiler to place variable in CPU register

No particular equivalent.  The "inverse" exists, "aliased", which
disallows use of a register.

> 
> synchronized  (Java) modifier to specify thread-safe methods

protected, though it is on a per-type basis, rather than a per-operation basis.

> 
> static:    linkage for variables and functions

Declare in enclosing package (see above discussion about "auto")

> 
> template:    set of parameterized classes or functions

generic

> 
> virtual:    polymorphism for functions, for classes to disable multiple
> members while using multiple inheritance

dispatching operation of a tagged type.  This is per-type in Ada rather
than per-operation.  If a type is marked "tagged" then all of its
primitive operations are effectively "virtual."  If not marked tagged,
then none of its primitive operations are virtual.   Non-primitive
operations are never "virtual."

> 
> transient  (Java) modifier used in the declaration of variables

No particular equivalent.  Would probably be done with a pragma in Ada.

> 
> volatile:    type qualifier; object can be modified in the program by
> something other than statements, such as the operating system, the hardware,
> or a concurrently executing thread

pragma Volatile  (also see pragma Atomic, which is related).

> 
> Thank you very much in advance for any help!
> 
> cu,
> alex

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA

Re: Q:ADA/Java/C++ feature mapping question!?

[Ted Dennison]

In article <38875E47.75A994CA@averstar.com>,
  Tucker Taft <stt@averstar.com> wrote:
> alex wrote:
> > register:    "asks" compiler to place variable in CPU register
>
> No particular equivalent.  The "inverse" exists, "aliased", which
> disallows use of a register.

Since C compilers usually ignore "register", you could say that the Ada
eqiuvalent is the following comment:
   -- Please please please compiler, place this object in a
   -- register. I'll be your best friend...

--
T.E.D.

http://www.telepath.com/~dennison/Ted/TED.html


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Re: Q:ADA/Java/C++ feature mapping question!?

[Brian Rogoff]

On Thu, 20 Jan 2000, Tucker Taft wrote:

> alex wrote:
> > 
> > Question: What are the corresponding ADA keywords to the given C++/Java
> > features, and which keywords do exist in ADA which have no representation in
> > C++/Java, and what do they mean. I did have a look at the
> > http://www.adahome.com/rm95/ Ada reference Manual, but this would be a
> > longer way to go then I would like to. So could one of you who knows both
> > languages help me out?
> > 
> > C++/Java Keywords of interest to me:
> > 
> > interface    (Java)  concept for abstract interface suitable for multiple
> > inheritance
> 
> Generic signatures are about the closest thing in Ada 95.  A generic
> signature is a generic package declaration with only a formal part,
> and no declarations in the visible part.  They are useful in combination
> with formal package parameters.

Not really quite the same, since they are really "package interfaces" rather 
than "type interfaces" as in Java . Its not as easy to combine them as it is 
to combine Java interfaces either, or more specifically, no equivalent to 
SML's "include". That said, they are quite useful. 

You mentioned previously that something like Java interfaces was likely to
find its way into the next generation Ada. Are there any pointers to
proposals we could look at?

-- Brian

Re: Q:ADA/Java/C++ feature mapping question!?

[carlislemc]

Since OO is done differently in these languages, it would be hard to
answer your question by a simple translation table.  I'd recommend
reading a text that describes the OO features of Ada.  For a thorough
presentation, see Cohen "Ada as a Second Language".  For a high-level
overview, try Sebesta "Concepts of Programming Languages" (note this
doesn't cover any of the advanced features, just the basics).

--Martin

In article <8672ec$e28$1@fleetstreet.Austria.EU.net>,
  "alex" <nulldevice@hotmail.com> wrote:
> Hi,
> my question should be easy to answer for anyone who knows C++/Java
and ADA.
> Unfortunately I only know C++&Java :-(.
>
> Question: What are the corresponding ADA keywords to the given
C++/Java
> features, and which keywords do exist in ADA which have no
representation in
> C++/Java, and what do they mean. I did have a look at the


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Before you buy.

Re: Q:ADA/Java/C++ feature mapping question!?

[alex]

Hi Martin,
many thanks for your answer. It is the prove for my preliminary conclusion
after continuing to read the Ada Reference Manual. It is somehow possible to
map the concepts of ADA and C++, but not the languages "meta model".

cu,
alex

<carlislemc@my-deja.com> wrote in message
news:867a85$6m9$1@nnrp1.deja.com...
> Since OO is done differently in these languages, it would be hard to
> answer your question by a simple translation table.  I'd recommend
> reading a text that describes the OO features of Ada.  For a thorough
> presentation, see Cohen "Ada as a Second Language".  For a high-level
> overview, try Sebesta "Concepts of Programming Languages" (note this
> doesn't cover any of the advanced features, just the basics).
>
> --Martin
>
> In article <8672ec$e28$1@fleetstreet.Austria.EU.net>,
>   "alex" <nulldevice@hotmail.com> wrote:
> > Hi,
> > my question should be easy to answer for anyone who knows C++/Java
> and ADA.
> > Unfortunately I only know C++&Java :-(.
> >
> > Question: What are the corresponding ADA keywords to the given
> C++/Java
> > features, and which keywords do exist in ADA which have no
> representation in
> > C++/Java, and what do they mean. I did have a look at the
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.

Re: Q:ADA/Java/C++ feature mapping question!?

[alex]

Many thanks to all that responded to my question. You have been of great
help to me! Very friendly newsgroup!

Thanks,
alex

"alex" <nulldevice@hotmail.com> wrote in message
news:8672ec$e28$1@fleetstreet.Austria.EU.net...
> Hi,
> my question should be easy to answer for anyone who knows C++/Java and
ADA.
> Unfortunately I only know C++&Java :-(.
<SNIP>