Custom Language

---

Program starts with "PROGRAM" keyword followed by "ID"(program name)

   PROGRAM Part10 { } 

Variable declaration

    var x, y : integer;
    var s    : real; 
    var c    : string;
    var f    : boolean;
    
    var a1   : integer = 5;
    var c, s : string = "same values"

Assignment statements

    x = 1 * 2 + 3 - 4 / 5 * (1 + 2)
    f = true;
    s = 1.5;
    c = "My language"

Boolean expressions

    flag = True and False or !False and (True and False)
    flag = 1 < 2 and 2 > 1 

Function declaration

    function foo(s: STRING) {
        VAR c : STRING;
    }   

Builtin functions

    function foo(s: STRING) {
        ... 
        print(s) 
    
        function bar() {
            return 2;
        }
        
        return bar(); 
    }   
    
    print(foo("bar")); // prints 2

Function call

    foo("Custom" + " " + "language");

If statement

    x = 10 
    if x > 5 
    {
        print("x is greater than 5");
    }
    elif x < 5
    {
        print("x is less than 5")
    }
    else
    {
        print("x equals to 5")
    }

    if true or false
    {
        print("true")
    }
    
    if true and !false
    {
        print("true")
    }

For loop

    for i = 0; i < 10; i = i + 1 {
        for j = 0; j < 10; j = j + 1 {
            for k = 0; k < 10; k = k + 1 {
                print(i * j * k)
            }   
        }       
    }   

Comments

    // This is one line comment 
    
    {{
        This is multi-line comment
    }}

Program snippet

    
PROGRAM Part10
{
    function fib(n: int) {
        if n < 1 {
            return 0;
        }
        elif n < 3 {
            return 1;
        }
        return fib(n - 1) + fib(n - 2);
    }


    for i = 0; i < 10; i = i + 1 {
        print(fib(i));
    }

}