Introduction
It is amazing how quickly something becomes the de facto standard
in our industry. Take Java, for instance. Not even a decade old and
already companies, universities, and independent programmers have
eschewed all other choices in favor of this dark brewed wonder. However,
from a technical standpoint, does Java really deserve this rapid exaltation?
When comparing Java to C++, Java has some very positive aspects. On
the other hand, there are instances where C++ is the correct choice
and not the hindrance often portrayed by the media. Many companies,
who were building their internal enterprise infrastructure with C++,
are choosing Java because it seems close enough to C++.
There are other languages besides C++, so why is it always necessary
to compare everything to C++? Instead of comparing Java with C++,
consider comparing Java with Smalltalk. After all, Smalltalk inspired
Java more than C++. In addition, vendors have positioned Smalltalk
to service the same set of problems as Java, namely enterprise business
software and there are several Smalltalks on the market that out perform
Java for developing shrink-wrap software.
A Crash Course in Smalltalk
To set the stage we start with a quick introduction to Smalltalk.
There are two aspects to consider when dealing with Smalltalk. The
first is the language itself, which is incredibly simple and consistent
across vendor products. The second is each Smalltalk vendor's product.
While all of the Smalltalk products on the market today follow the
same basic design, there are important differences.
100% Object Oriented - No Cream Please
Smalltalk is 100% object-oriented; often called a pure
object-oriented system. There is confusion since many believe that
Java is also 100% object-oriented. There are no primitive types
in Smalltalk, as there are in Java, which requires explicit conversion
to and from object form. In addition, there is inheritance from any
class within a Smalltalk image without restriction. These two traits
represent enormous design latitude for the Smalltalk programmers,
which are not available to the Java programmer. The programmer no
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concerns himself with a multi-paradigm
type system nor works around arbitrary vendor specified firewalls
within a class library. Although many argue the benefits of a
single paradigm programming language, especially those that are object-oriented
in nature, Smalltalk's simple and consistent paradigm has demonstrated
that it allows rapid software development.
An Object Database
Before moving on, there is a term mentioned above that
might not be familiar. An image is a type of object database that
stores an active snapshot of the entire Smalltalk development environment.
Since many Smalltalk development environments use green threads (also
called fibers under Windows), an image also saves an exact snapshot
of every task currently running. When reloading the image, everything
returns to the state it was in when Smalltalk created the image. This
is an extremely powerful tool and the image itself can store any type
of data.
A Natural Language Approach
Smalltalk's syntax is very similar to that of a natural
language. The syntax pattern is always object verb. In Smalltalk parlance,
one calls the verb a message and one sends these messages to an object.
When reading Smalltalk, always read it left-to-right, without exception
as it makes reading and writing the language very easy.
There are three different forms of this basic linguistic
construct in Smalltalk. If this were a grammar class, these would
be our cases:
'Hello World' asUppercase.
1 + 2.
'Hello World' beginsWith: 'Hello'.
The first is the unary case, where the object (a
String in this case) receives the message asUppercase.
The second is the binary case, where the SmallInteger 1 receives the
message + with a single SmallInteger parameter of 2. The binary case
is only available on a limited number of selectors, which varies by
Smalltalk. The term selector is a synonym for method in Smalltalk,
but it specifically refers to the key in a method dictionary. |
