Do Blocks

There is a final function-related issue that might happen when you code in Ryna. It can be solved with a new feature called do blocks, so let's take a look:

The problem

Imagine you want to create a variable called var and you want to assign it the value a or b depending on a condition c. Your first instict might be doing something like this:

let var;

if c {
    var = a;

} else {
    var = b;
}

The problem is, Ryna does not allow to declare a variable without initializing it. One way to solve this would be using a dummy value d:

let var = d;

if c {
    var = a;

} else {
    var = b;
}

But this creates two problems:

1. Your program does unnecesary steps, so performance may suffer.
2. d might not be available in generic contexts.

You cannot do this, so you will have to use do blocks;

Do blocks

A do block can be understood as a function body that will only be executed once. You could solve the previous problem like this:

let var = do {
    if c {
        return a;

    } else {
        return b;
    }
};

the syntax is self-explanatory and the semantics are the same as a function body, but without calls to any methods. Also, they allow you to access the context above it (unlike lambdas or regular functions). These are the blocks that are used to compile function macros, but we will take a look at that in a later section.