Download The CORA Programming Language

The CORA Programming Language
Jörn Fischer
Faculty of Computer Science
University of Applied Science Mannheim
68163 Mannheim, Germany
j.fischer at hs-mannheim.de
Abstract— CORA is a short form of “Compile Once Run
Anywhere“. The programming language is object orientated
and compiler based, running on a virtual machine called the
“Minimal Virtual Machine“(MVM). Due to the tiny size of
the MVM’s kernel, the virtual machine may be ported to any
platform within a few hours. The language is highly inspired
by JAVA [1] and C/C++ [2] and tries to include large parts of
the syntax of both languages. The following article summarises,
what functionalities are covered in the actual version.
void sort(double numbers[]){
// bubble sort algorithm
int N = numbers.length;
for (int i=0; i<N; i++){
for (int j=0; j<N-1; j++){
if (numbers[j]>numbers[j+1]){
double help = numbers[j];
numbers[j]
= numbers[j+1];
numbers[j+1] = help;
}
}
}
I. I NTRODUCTION
The name CORA, “Compile Once Run Anywhere“implies
that the code is compiled to an intermediate code, which then
runs on a virtual machine called the CORA MVM (Minimal
Virtual Machine). The MVM kernel covers about 2-3 pages
of C/C++ code and therefore is easyly ported to any platform.
The MVM is also ported to JAVA and JavaScript, languages
which are highly disposable.
II. K EYWORDS
The following table shows the keywords which are actually implemented in CORA. All keywords exist in JAVA, C++
or even in both of these languages.
break
goto
return
void
class
new
if
double
case
static
float
asm
private
public
extends
char
switch
boolean
byte
int
long
const
do
else
short
while
for
III. L ANGUAGE AND S YNTAX
As the code example in Fig.1 shows, the code is widely
compatible with the JAVA and C/C++ syntax.
There are “for“-loops, “while“- and “do-while“-loops. The
“for-each“-loop is NOT implemented yet! Please always use
curly brackets {} for the block to be repeated.
The “if-else“expression should also contain curly brackets
for the if-blocks and for the else-block. Please do not use
the “else-if“expression, but “else{ if(condition){...block...}
}“instead. The “switch-case“expressions should work fine.
Arrays are implemented as one dimensional arrays and
may be declared using the new operator. The declaration of
an array by assignment of multiple numbers in curly brackets
is NOT supported yet.
}
Fig. 1.
A simple bubble sort example method.
IV. DATA T YPES
The following elementary data types are defined:
char, byte, short, int, long, float, double. Because the
actual MVM is based on floating point operations,
“double“variables are always treated with the precision of
floats. Declarations may be made outside of methods, but
variable initialization must always be done in methods.
V. O PERATORS
The following Operators are implemented:
Name
brackets
negate increment decrement
Arithmetic Operators
shift operators
compare operators
Symbol
() []
! ++ −−
∗/%
+−
<< >>
> >= < <=
== ! =
Priority
13
12
11
10
9
8
7
The priority of the operators should be the same as in
JAVA. Brackets always have the highest priority.
VI. F UNCTIONS /M ETHODS
As in JAVA methods are declared with an optional
“public“or “private“, then the data type of the return value,
the name of the method and in brackets the arguments of the
method. The return statement or the closing curled bracket
ends the method. As in C++ the public: or private: statement
defines the following functions and variables as public or
private.
VII. O BJECT O RIENTED C OMPONENTS
All declarations, functions, assignments and commands
are organized in classes. From these classes, objects may
be generated with the new operator. Until now it is possible
to call functions with the dot operator, while for the moment variables have to be manipulated via setter and getter
functions.
Objects are generated as references. Assigning objects will
only change the reference, not the object itself. For the
moment there is neither a copy constructor nor a clone()
method. Even interfaces are missing.
Using the JAVA-keyword extends or the C++ way “class
Name :public Basename“enables inheritance.
VIII. L IBRARIES
There are no C/C++ or Java libraries implemented.
IX. F UTURE WORK
First goal is to get a stable programming language, where
bugs are recently reported and corrected in a short time.
Second goal is to implement the main kernel functionality
of Java and C/C++. Third goal is to implement a minimum
of libraries and documentation, which help the programmer
to write simple programs.
ACKNOWLEDGEMENT
Special thanks to Thomas Ihme and Robert Kettler who
helped with fruitful discussions.
R EFERENCES
[1] K. Arnold and J. Gosling. The Java Programming Language. The
Java Series. Addison-Wesley, Reading, Massachusetts, 1996.
[2] Brian W. Kernighan and Dennis M. Ritchie. The C Programming
Language. Prentice-Hall, 2nd edition, 1989.