KarboScript

Simple programming language made for fun to learn how parsers and compilers works. Don't have much capability but have the basic stuff like functions, if, loops.

Main program

Each program has to have main() function:

function main() {
    //add your code here
}

This is the starting point of every script.

Usage

Execute script.ks file

# ./karboscript script.ks

Show opcodes for script.ks file

# ./karboscript --opcode script.ks

Buildin functions

We have to our disposal couple of buildin functions:

function name	arguments	return	example
out()	any variable...	nothing	out(1,2,3);
readLine()	nothing	string	name = readLine();
readInt()	nothing	int	name = readInt();

Syntax

Declare function

function <name>([<type> <argument_name>], ...) [return_type] {
    [body]
}

Declare variable

<type> <var_name> = <expression>;

For example: string test = "hello world";

Array

array <var_name> = [<expression>, ...];

Access array element

<array_name>[<index>]

Assign array element

<array_name>[<index>] = <expression>;

Push new element to array

<array_name>[] = <expression>;

Call function

<function_name>(<argument>, ...);

For example: func(1, 2, 3, variable);

Loops

While

    while (<expresion>) {
        [body]
    }

For

    for <init_statement>; <compare_expresion>; <inrement_statement>; {
        [body]
    }

From to

    from <starting_value_expresion> to <ending_value_expresion> as <variable_name>; {
        [body]
    }

Examples

Fibonaci:

function main() {
    int a = 1;
    int b = 1;

    while (b < 500) {

        c = b;
        b = a + b;
        a = c;
        out (b);
    }
}

while loop:

function main() {
    int a = 1;
    int b = 1;

    while (a < 5) {
        b = 1;
        while (b < 5) {
            out ("test", b);
            b=b+1;
        }

        a=a+1;
    }
}

If statement

function main()
{
    if (10 == 10) {
        out("10 == 10");
    }
    if (500 < 200) {
        out("500 < 200");
    }
    if (12 > 10) {
        out("12 > 10");
    }
}

Arguments for function

function main()
{
    out(1000 + test(800), test(500));
}

function test(int test)
{
    return test + 200;
}

For loop

function main() {
    for int i=0; i<10; i=i+1; {
        out(i);
    }
}

For increment (loop from one expresion to another with interval of 1)

function main() {
    from 0 to 10 as i {
        out(i);
    }
}

Read line from stdin

function main() {
    out("Enter name: ");
    name = readLine();
    out("Your name is:", name);
}

Return type

function main() {
    out(test());
}

function test() string {
    return "test";
}

Array declaration

function main() {
    array a = [1, 2, 3, 4, 5];
    out(a[0]);
}

Array assignment

function main() {
    array a = [1, 2, 3, 4, 5];
    a[0] = 10;
    out(a[0]);
}

Intermediary code

The code is compiled to intermediary code which is then executed by virtual machine. For example this code:

function main() {
    int a = 1;
    int b = 1;
    int max = 500;
    while (b < max) {
        out (b);

        int c = b;
        int b = a + b;
        a = c;
    }
}

Will be compiled to:

"_function.main: function"
"add_scope"
"push_exp ( 1 )"
"sub_scope"
"set_local_var_exp ( int a )"
"add_scope"
"push_exp ( 1 )"
"sub_scope"
"set_local_var_exp ( int b )"
"add_scope"
"push_exp ( 500 )"
"sub_scope"
"set_local_var_exp ( int max )"
"_while.d: while_start"
"add_scope"
"push_exp_var ( b )"
"push_exp_var ( max )"
"exp_call ( < )"
"sub_scope"
"while ( _while.13 )"
"add_scope"
"push_exp_var ( b )"
"sub_scope"
"push_function_arg"
"call_function ( out 1 )"
"add_scope"
"push_exp_var ( b )"
"sub_scope"
"set_local_var_exp ( int c )"
"add_scope"
"push_exp_var ( a )"
"push_exp_var ( b )"
"exp_call ( + )"
"sub_scope"
"set_local_var_exp ( int b )"
"add_scope"
"push_exp_var ( c )"
"sub_scope"
"set_local_var_exp (  a )"
"jmp ( _while.d )"
"_while.13: while_else"
"function_return"
"call_function ( main 0 )"
"exit ( main 0 )"