make_postfix_expression_Practical1_part2

function make_postfix_exp(bae){
    
    if (is_number(bae)){
        return [bae];
    }
    
    const postfix = [];
    
    function append_array(a){ // add elements to end of array
        for (let i = 0; i < array_length(a); i = i + 1){
            postfix[array_length(postfix)] = a[i];
        }
    }
    
    // tree like structure
    // wishful thinking
    
    const left = make_postfix_exp(bae[0]);
    const right = make_postfix_exp(bae[2]);
    const op = bae[1];
    
    append_array(left);
    append_array(right);
    
    postfix[array_length(postfix)] = op;
    
    return postfix;
    
}

make_postfix_exp([[[30, "/", 3], "-", 1], "*", [4, "+", 6]]);