Number Type - num

The num type is a special type that represents a number (both floating point and integer) in the Kipper language. This datatype may always be used with the standard mathematical expressions.

Order or evaluation

When working with numbers watch out for the order of evaluations of arithmetic expressions. Kipper will interpret mathematical calculations as defined in the standard math conventions i.e. multiplications, divisions and power-to operations have a higher priority than additions and subtractions.

Simple example:

var result: num = 4 + 4 * 5; // 4 + (4 * 5) -> 24

These are also defined in the table of operator precedence.

Octal, Hex and Binary numbers

Besides the regular Base-10 numbers, you may also use Hex, Octal and Binary numbers, as long as they are prefixed with the correct identifier:

• Binary numbers are prefixed with 0b:

  var bytes: num = 0b11111010; // -> 250

• Hexadecimal numbers are prefixed with 0x:

  var hex: num = 0xffa2; // -> 65442

• Octal numbers are prefixed with 0o:

  var octal: num = 0o347; // -> 231

Note that the numbers stored in the variables are always stored as Base-10 numbers, so converting them to a string will always result in a Base-10 number.

This also means that you may mix different number types together, as long as they are prefixed with the correct identifier:

var octal: num = 0o347 + 150 + 0xffa2; // -> 65823

Safe Number Range

Due to the fact that Kipper only compiles to TypeScript or JavaScript, the underlying number type will almost always be a 64-bit floating point number. This means that the maximum safe number range is the same as in JavaScript, which is Number.MAX_SAFE_INTEGER.

Over this limit, the numbers will start to lose precision, as shown in the following example:

var num1: num = 9007199254740991; // -> 9007199254740991
var num2: num = 9007199254740992; // -> 9007199254740992
var num3: num = 9007199254740993; // -> 9007199254740992

Performing equality checks now causes the following problem:

var isEqual = num3 === 9007199254740993; // -> true
print(isEqual as str) // -> true

isEqual: bool = num3 === num2; // -> true (but should be false)
print(isEqual as str) // -> true

isEqual = num3 === 9007199254740992; // -> true (but should be false)
print(isEqual as str) // -> false

This is due to the fact that the numbers are stored as floating point numbers, which are not able to represent the number with full precision.

Examples

Simple integer variable definitions

var var1: num = 400;

Simple floating point variable definitions

var var2: num = 0.43493;

Calculations using floating point and integer numbers

var var3: num = var2 + var1; // -> 400.43493

Arithmetic Expressions

The following arithmetic expressions are supported (as also shown in arithmetical expressions):

• Addition:

  var var1: num = 400.3 + 26.3; // -> 426.6

• Subtraction:

  var var2: num = 87 - 2.5; // -> 84.5

• Multiplication:

  var var3: num = 2.4 * 5; // -> 12

• Division:

  var var4: num = 25 / 4; // -> 6.25

• Power to:

  var var5: num = 2 ** 8; // -> 256

• Rest of Divide (Modulo):

  var var6: num = 51 % 10; // -> 1