Integer Literals

Plain

Integer constants are sequences of digits. A prefix + or - can be added to set the sign. Integers can be assigned to variables of integer types: i8, i16, i32, i64, u8, u16, u32 and u64.

Overflows

Values that do not fit into the type they are assigned to will cause a compile time error:

Grouping

Digits in a constant may be grouped using underscore characters _. The underscores must create groups of digits of equal sizes, only the first group can be smaller. This grouping can be used to improve readability, e.g., to use groups of three to separate thousands, millions, etc., in decimal numbers or to group bytes in binary numbers:

million  := 1_000_000
billion  := i64 1_000_000_000_000          # sorry, Americans, a billion is a million squared!
trillion := i64 1_000_000_000_000_000_000  # and a trillion is a million cubed.
say "$million $billion $trillion"

debug_marker := u64 0x_dead_beef_c0de_bad1
say debug_marker.hex

for n in [ 0b_00000000_00011111_11111000_00000000,
           0b_00000000_01100000_00000110_00000000,
           0b_00000000_10000000_00000001_00000000,
           0b_00000001_00001100_00110000_10000000,
           0b_00000010_00001100_00110000_01000000,
           0b_00000010_00000000_00000000_01000000,
           0b_00000010_00000000_00000000_01000000,
           0b_00000001_00110000_00001100_10000000,
           0b_00000000_10001111_11110001_00000000,
           0b_00000000_01100000_00000110_00000000,
           0b_00000000_00011111_11111000_00000000 ]
do
  s0 := n.bin
  s1 := s0.replace "0" " "
  s2 := s1.replace "1" "M"
  s3 := " " * (32-s2.codepoint_length) + s2
  say s3

What are effects?

Groups of different sizes will cause a compilation error:

Bases

Integer constants can be given in decimal, binary, octal or hexadecimal representation. A prefix 0d, 0b, 0o or 0x, respectively, selects the base to be used. If no prefix is given, decimal representation using base 10 is used as default.

Exponents

Integer constants may use an exponent. Exponents are introduced using E or P, where E introduces an exponent to base 10, while P introduces an exponent to base 2.

Fractional Parts

Integer constants in Fuzion may come with a fractional part, as long as the resulting number is an integer.

If the resulting number is a fraction, it cannot be used as an integer:

Types

The default type of an integer literal is i32. If you need the literal to be of a different type you either need to specify the type of the field or use the corresponding constructor.

When performing calculations with integer literals using infix operators, the type of the calculation depends on the left operand:

To explicitly choose a type for a literal, place the name of the type in front of it as in u64 1:

When adding the type explicitly before the integer literal, you actually call the constructor of that type given the constant as an argument. All built-in numeric types have a constructor with one argument val that has the same type. Consequently, the type inference mechanism forces that type onto the constant.

last changed: 2024-08-13

next: Float Literals