README.md

Banana programming language

Banana, a toy VM-based programming language.

Sample code

long fib(long n) {
    if (n == 1 or n == 2) {
        return n;
    }
    return fib(n - 1) + fib(n - 2);
}

int main() {
    for (long i = 1; i < 10; i++) {
        print fib(i);
    }
}

Prerequisites:

sudo apt install g++ cmake libffi-dev

Compile Banana:

git clone --recurse-submodules https://github.com/omaraflak/banana
cd banana
cmake -B build
cmake --build build

Run program:

./banana -i <source.na>

Features

Currently, the language is very limited and supports the following features.

Types: bool, char, int, long.

The language supports automatic casting of types when needed.

Constructs: if, else, for, while, return.

Binary Operators: +, -, *, /, %, ^, &, |, <, <=, >, >=, ==, !=, and, or, +=, -=, *=, /=, %=, ^=, &=, |=.

Unary Operators: =, -, !, ~, ++, --.

Std library: print.

Native C Calls: @native()

You can call native C code from Banana, provided that you expose the code in a shared library.

mylib.cpp:

#include "../src/lib/c_interface.h"

long do_something(long n) {
    // something complicated here
    return 2 * n;
}

class MyNativeFunction : public CInterface {
    cinterface::ArgType get_return_type() const { return cinterface::LONG; }
    std::vector<cinterface::ArgType> get_arg_types() const { return {cinterface::LONG}; }
    std::string get_name() const { return "math::do_something"; }
    void* get_function() const { return (void*) do_something; }
};

std::vector<CInterface*> get_classes() { return {new MyNativeFunction()}; }

Compile this as a shared library:

g++ mylib.cpp -o lib_folder/mylib.so -shared -fPIC

Bind it in Banana:

@native("math::do_something")
long doSomething(long n);

int main() {
    print doSomething(10);
}

Provide the shared library directory with --lib when running the code:

./banana -i myscript.na --lib lib_folder

CLI

Run code from compiled file

$ ./banana source.obj

Run code from source file

$ ./banana -i source.na

Compile source file

$ ./banana -c source.na

Print VM instructions from source file

int add(int a, int b) {
    return a + b;
}

int main() {
    print add(5, 6);
}

$ ./banana -a source.na
0       jump 48
9       store 0
18      store 1
27      load 0
36      load 1
45      add
46      ret 1
48      push int 6
54      push int 5
60      call 9 2
70      print
71      push char 10
74      print
75      halt