Syntax

Comments

Comments are any text following // up until a new line.

// A comment
std\print("Comment ended with a new line");

Variables and identifiers

A variable declaration is a qualifier (either var or final) followed by an identifier and a type which can be omitted

final hello: str = "hello";
var bye = "bye"; // Here the `str` type will be inferred from the initial value

An identifier must start with a letter and can consist of letters, numbers and the _ character.

final helloWorld2 = "valid";
final hello_world = "valid too";

However you can actually use anything as an identifier if you surround it with the @"..." notation.

final @"this is valid too!" = "hello";

A nullable variable can omit its initial value which will automatically be null:

var maybe: str?;

assert(maybe == null);

final

A final variable can only be assigned once

final hello = "hello";

hello = "bye"; // Not allowed

Operators

Comparison

"hello" == "hello";
12 != 13;
12 >= 12;
12 <= 12;
12 > 11;
12 < 13;

int and double can be compared with one another.

Arithmetic

12 + 12 == 24;
12 - 12 == 0;
12 * 12 == 144;
12 / 12 == 1;
12 % 12 == 0;

Arithmetic operators are allowed between numbers of the same type.

Logical

12 > 3 and 5 < 12;
12 > 3 or 12 < 5;

Concatenation

The + operator can also be used to concatenate strings, lists or maps (of the same type).

"hello " + "world" == "hello world";
[ 1,2,3 ] + [ 3, 4, 5]      // -> [ 1, 2, 3, 3, 4, 5, ]
{ "one": 1 } + { "two": 2 } // -> { "one": 1, "two": 2 }

Bitwise

15 << 3 == 120; // shift left
15 >> 3 == 1;   // shift right
12 & 23 == 4    // and
15 ^ 3 == 12;   // xor
15 | 3 == 15;   // or
~15 == -16;     // not

Null safety

mightBeNull ?? defaultValue; // Will result in `defaultValue` if `mightBeNull` is null

See Null safety.

Type operators

something is str;  // true if `something` is of type `str`
something as? int; // if `something` is not an `int`, will result in a `null`

See Null safety, any type.

typeof myList == <[int]>; // returns type of expression