Integers

An integer literal is an optional or - sign, followed by a sequence of digits and underscores, optionally followed by a suffix. If no suffix is present, the literal’s type is the lowest between Int32, and UInt64 in which the number fits (at the moment, 128 bit integers must always be suffixed):

Underscores can be used to make some numbers more readable:

Octal numbers start with a 0o: