This is a simple compiler for self-defined P language, which can be viewed as a simplified version of Pascal. The whole skeleton of the compiler is as follows:
Actually, this is the term project for my course Intro. to Compiler Design. So the syntax of P refers to the documents offered by our professor, which can be found in docs.
make && ./compile.sh [programname].p
java [programname]
Here is the code in test.p, which takes an integer as input and invokes a recursive function to calculate the corresponding Fibonacci Number:
// test.p
test;
fib( x: integer ): integer;
begin
if x = 0 or x = 1 then
return x;
end if
return fib(x-2) + fib(x-1);
end
end fib
begin
var a, result: integer;
print "Please enter an integer\n";
read a;
print "Fibonacci number F";
print a;
print " is ";
print fib(a);
print "\n";
end
end test
make the compiler and compile the above code:
make && ./compile.sh test.p
Then test.class is created and we use JVM to run it:
java test
We get the following result:
Please enter an integer
8
Fibonacci number F8 is 21