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From: lozinski@argon.uucp (Chris Lozinski)
Newsgroups: comp.object,comp.lang.c++
Subject: Choice of language for manufacturing Applications
Message-ID: <26686@pasteur.Berkeley.EDU>
Date: 2 Aug 90 16:01:03 GMT
Sender: news@pasteur.Berkeley.EDU
Reply-To: lozinski@argon.UUCP (Chris Lozinski)
Lines: 153



INTRODUCTION

  After trying Basic, Fortran, Scheme, C, APL, and Objective-C, I 
became firmly convinced that Objective-C was the best language
choice for the manufacturing applications that I work with.  Then
when C++ became a common language, I carefully researched the
language, read the manuals, talked to people and generally tried to
make a wise long term decision.   This article summarizes the
reasons behind my growing conviction that Objective-C is a
preferable language to C++ for manufacturing application.  
           

EVOLUTIONARY DIFFERENCES

   Objective-C has evolved from Smalltalk where the emphasis is on
programmer productivity.  C++ has evolved from C where the emphasis
is on speed and memory requirements.  With the falling prices of
workstations, and rising costs of software development, the
tradeoffs need to be carefully considered.  I.M.H.O. Objective-C is
the better choice in manufacturing applications.


ORGANIZATIONAL DIFFERENCES

    C++ is the computer scientists language where the focus is on 
technical aspects of the language.  Objective-C is the
businessman's language, where the emphasis is on organizing large
groups of people into cooperating communities assembling components
into final applications.  Technically this is caused by the default
structures of the objective-C language where the target class of a
message does not need to be known at compile time.  In contrast the
default in C++ is that the target class does need to be known at
compile time.


BUSINESS DIFFERENCES

   Stepstone is tightly focussed on creating tools for software
developers.  AT&T by contrast is not in the market of selling
software tools, and therefore cannot be expected to react as
quickly to market requirements.  
    

TECHNICAL DIFFERENCES
    
1)    The key feature that distinguishes Objective-C from C++ is
the maintenance of symbol tables.  Here I must agree with jsweet of
Nasa.  Objective-C allows the user to issue the following command

      [anObject perform: "aMessage"];
      or alternatively

       aSelector = convertToSelector("aMessage");
       [nObject perform aSelector];

This command means send the message "aMessage" to the object called
anObject.  This ability is critical for simplifying interprocess
communication, either between objects on different operating
systems, or between a person and the computer.   I highly recommend
that people take a close look at the design of the NextStep user
interface which profits from this approach.  As for distributed
processing, time alone will demonstrate the power of this approach.



2)   The key feature that distinguishes C++ from Objective-C is
operator overloading.  This allows the user to deal with structures
such as vectors scalars and matrices in a very natural fashion.

             float aScalar;
             vector aVector;
             matrix aMatrix, anotherMatrix;
             aVector = aScalar * aVector;
             anotherMatrix = aVector * aMatrix;


   In manufacturing applications the more powerful Objective-C
messaging is more valuable to me than the operator overloading of
C++.


EASE OF USE
  
   C++ supports and encourages the use of pointers to data
structures.    The type of the data structure is known at run time.
Pointers, and dereferencing dominate the minds of the users and
invariably confuse the beginners.  In contrast Objective-C supports
and encourages the use of sending messages to objects, and
historically discourages the manual navigation of pointers.  My
experience has been that the concept of sending messages to objects
proves much easier to understand (and debug) than the whole issue
of navigating pointers and dereferencing locations.   



 DEVELOPMENT TIME.

   Both of the people I have known who have extensive development
experience in both C++ and Objective-C claimed that software could
be developed in Objective-C faster.   As a professional software
developer, my primary cost is software development time, so this is
a critical advantages.


 PLENTIFUL TOOLS
    
    There is a growing list of Objective-C tools.  Here is my
current list.


   StepStone Compiler

   Stepstone Foundation Library

   Stepstone User Interface Library
 
   StepStone Browser 

   GNU debugger
  
   GNU compiler

   CNS Microsoft Windows Bindings.

   CNS Browser for DOS

   CNS Application code streamliner

   CNS Objective-C make utility

   NeXTStep libraries for NeXT and IBM machines.

   GEMSTONE INTERFACE (rumored)




CONCLUSION
 
    The choice of language is totally driven by the application's
needs.   My area of expertise is distributed customized
manufacturing applications, where the emphasis is on speed of
development, a powerful user interface paradigm and flexibility of
the tools.  For these needs Objective-C is wonderfully suited.
I highly recommend the language to everyone in this field.
   
      
NON-STANDARD DISCLAIMER

   My enthusiasm for the language is so strong that I have chosen
to base my product on it.   This makes me a biased observer.