Basic Data Types

Original Blitz has three basic data types: Integer, Float, and String. A value's type determines how it is stored, which operations it supports, and how it is converted when combined with another type.

Extended mode also provides true 64-bit Long and Double basic types.

The traditional %, #, and $ tags work in every dialect. :Int, :Float, and :Str are available with Dialect "modern". If no type is stated, a variable, Field, array, parameter, or Function return value defaults to Integer.

Integer

An Integer is a signed 32-bit whole number. Its range is -2147483648 to 2147483647. Integer literals have no decimal point:

Local score% = 1200
Local offset% = -16
Local count% = 0

Comparison and Boolean expressions also produce Integer results: True is 1 and False is 0. In a condition, zero is false and any non-zero Integer is true.

Float

A Float is a 32-bit IEEE 754 single-precision number. It can represent a fractional value and has approximately seven significant decimal digits of precision, with a maximum finite magnitude of approximately 3.4 × 10^38.

A Float literal includes a decimal point, even when its fractional part is zero:

Local speed# = 2.5
Local temperature# = -10.25
Local origin# = 0.0

Most decimal fractions cannot be represented exactly in binary floating point, so the stored result may be a close approximation.

String

A String contains text. A String literal is enclosed in double quotation marks, and "" is the empty String:

Local playerName$ = "Ranger"
Local message$ = "Ready"
Local emptyText$ = ""

The + operator concatenates Strings. Strings may also be compared using the comparison operators.

Local fullMessage$ = playerName$ + ": " + message$
If playerName$ = "Ranger" Then Print fullMessage$

Declaring types

Traditional type tags follow the identifier:

Local lives% = 3
Local gravity# = 9.8
Local title$ = "Arena"

Modern annotations provide equivalent named forms:

Dialect "modern"

Local lives:Int = 3
Local gravity:Float = 9.8
Local title:Str = "Arena"

A type tag or annotation is part of a declaration's type. The same identifier cannot be declared again with a different type. See Variables for declaration and scope rules.

Conversions

Int, Float, and Str explicitly convert a value to the corresponding basic type:

whole% = Int(12.6)
decimal# = Float("3.5")
text$ = Str(100)

Mixed-type expressions may also convert an operand automatically. See Operators and Conversions for the conversion order and operator rules, and Constants for literal and named-constant syntax.

Other language types

Custom Types store references to structured objects and are not basic values. Extended mode additionally provides Enums, Interfaces, and typed List references; these retain their own type and compatibility rules. It also provides the basic Long and Double types described in Long and Double.