Control flow

if

The if statement is pretty much what you would expect.

| The usual
if (someCondition) {
    | ...
} else if (anotherCondition) {
    | ...
} else {
    | ...
}

You can unwrap an optional with the -> operator.

if (opt -> unwrapped) {
    print(unwrapped);
}

You can downcast a value with the as operator.

any anything = "hello";

|...

if (anything as str something) {
    print(something);
}

if can also be inlined and act as an expression. However this expression does not support null unwrapping or downcasting (those are available in expression using ?? and as?);

int value = if (something > 0) 12 else 13;

while and do .. until

Repeat a block of statements while or until a condition is true.

int i = 0;
while (i < 10) {
    i = i + 1;
}

int j = 10;
do {
    j = j - 1;
} until (j == 0)

for

for is pretty much the same statement as in C.

for (int i = 0; i < 10; i = i + 1) {
    | ...
    break;
}

foreach

foreach can iterate over most data structures. The key/index variable can be omitted.

foreach (SomeEnum case in SomeEnum) {
    | ...
}

foreach (int i, str value in listOfStrings) {
    | ...
}

foreach (str key, int value in aMap) {
    | ...
}

foreach (int i, str char in aString) {
    | ...
}

fib<void, int?> fibonnaciFib = &fibonnaci(10);
foreach (int value in fibonnaciFib) {
    | ...
}

| The key can be omitted
foreach (str char in aString) {
    | ...
}

foreach (int i in 0..n) {
    | ...
}

break and continue

break will stop a loop.

while (true) {
    if (condition) {
        break;
    }
}

continue will skip any following statement and start the loop again.

while (true) {
    if (condition) {
        continue;
    }

    print("not reached if `condition` is true");
}

You can add a label to any loop and break/continue to it. This is useful when you have nested loops and want to break to an upper scope:

while (true) :here {
    if (condition) {
        break here;
    }

    print("not reached if `condition` is true");
}

Block expression

Block expression are lexical blocks that produce a value:

var value = from {
    | Doing so work here...

    out result;
}

out must appear once at the end of the block.