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zscript-doc/language/Types.md

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Types

ZScript has several categories of types: Integer types, floating-point (decimal) types, strings, vectors, names, classes, et al. There are a wide variety of ways to use these types, as well as a wide variety of places they are used.

Types determine what kind of value an object stores, how it acts within an expression, etc. All objects, constants and enumerations have a type. Argument lists use types to ensure a function is used properly.

Most basic types have methods attached to them, and both integer and floating-point type names have symbols accessible from them. See the API section for more information.

Integer Types

Integer types are basic integral numbers. They include:

Name Usable as argument Bits Lowest value Highest value
int Yes 32 -2,147,483,648 2,147,483,647
uint Yes 32 0 4,294,967,296
int16 No 16 -32,768 32,767
uint16 No 16 0 65,535
int8 No 8 -128 127
uint8 No 8 0 255

Some types have aliases as well:

Name Aliases
sbyte int8
byte uint8
short int16
ushort uint16

Symbols

Integer types have symbols attached which can be accessed by typename.name, for instance int.Max.

Max

Maximum value of type.

Min

Minimum value of type.

Floating-point Types

Floating-point types hold exponents, generally represented as regular decimal numbers. There are two such types available to ZScript:

Name Usable as argument Notes
double Yes 64-bit floating-point number.
float Yes (64 bits) 32-bit in structures and classes, 64-bit otherwise.
float64 Yes Alias for double.
float32 No 32-bit floating-point number. Not implemented correctly, unusable.

Symbols

Floating-point types have symbols attached which can be accessed by typename.name, for instance double.Infinity.

Dig

Number of decimal digits in type.

Epsilon

ε value of type.

Infinity

∞ value of type.

Mant_Dig

Number of mantissa bits in type.

Max

Maximum value of type.

Max_Exp

Maximum exponent bits value of type.

Max_10_Exp

Maximum exponent of type.

Min_Denormal

Minimum positive subnormal value of type.

Min_Exp

Minimum exponent bits value of type.

Min_Normal

Minimum value of type.

Min_10_Exp

Minimum exponent of type.

NaN

Not-a-Number value of type.

Strings

Name Usable as argument
string Yes

The string type is a mutable, garbage-collected string reference type. Strings are not structures or classes, however there are methods attached to the type, detailed in the API section.

Names

Name Usable as argument
name Yes

The name type is an indexed string. While their contents are the same as a string, their actual value is merely an integer which can be compared far quicker than a string. Names are used for many internal purposes such as damage type names. Strings are implicitly cast to names.

Names can be converted to int with an explicit cast, and the negative of int(name()) may be used to create an integer representation of a string usable by action specials, most prominently Acs_NamedExecute.

Colors

Name Usable as argument
color Yes

The color type can be converted from a string using the X11RGB lump or a hex color in the format #RRGGBB, or with either of:

color(R, G, B)
color(A, R, G, B)

Vectors

Name Usable as argument
vector2 Yes
vector3 Yes

There are two vector types in ZScript, vector2 and vector3, which hold two and three members, respectively. Their members can be accessed through x, y and (for vector3,) z. vector3 can additionally get the X and Y components as a vector2 with xy.

Vectors can use many operators and even have special ones to themselves. See the Expressions and Operators section for more information.

Fixed-size Arrays

Name Usable as argument
Type Array-size No

Fixed-size arrays take the form Type[size]. They hold size number of Type elements, which can be accessed with the array access operator.

Multi-dimensional arrays are also supported, although the dimensions will be backwards (right to left instead of left to right) unless version is 3.7.2 or greater.

Note that this kind of type can also be declared in variable names themselves.

Dynamic-size Arrays

Name Usable as argument
array < Type > Yes

Dynamically sized arrays take the form array<Type>, and hold an arbitrary number of Type elements, which can be accessed with the array access operator.

Dynamic-sized arrays do not have their lifetime scoped to their current block, so the following:

for(int i = 0; i < 5; i++)
{
	array<int> a;
	a.Push(0);
}

Will result in an array with 5 elements.

Dynamically sized arrays also cannot store other dynamically sized arrays, or user-defined struct objects.

Maps

Name Usable as argument
map < Type , Type > No

Map types take the form map<Type, Type>. They are not yet implemented.

Class Types

Name Usable as argument
class < Type > Yes
class Yes

Class type references are used to describe a concrete type rather than an object. They simply take the form class, and can be restrained to descendants of a type with the syntax class<Type>. Strings are implicitly cast to class type references.

User Types

Name Usable as argument
Any class object Yes
Native struct object Yes
User-defined struct object No
@ Type Yes

Any other identifier used as a type will resolve to a user class, structure or enumeration type.

Types prefixed with @ are native pointers to objects (as opposed to objects placed directly in the structure's data.) This is not usable in user code.

A type name that is within a specific scope can be accessed by prefixing it with a .. The type .MyClass.MySubStructure will resolve to the type MySubStructure contained within MyClass.

Read-only Types

Name Usable as argument
readonly < Type > Yes

A read-only type, as its name implies, may only be read from, and is effectively immutable. They take the form readonly<Type>. Do note that this is separate from the member declaration flag.

Other Types

Name Usable as argument Description
bool Yes Holds one of two values: true or false.
sound Yes Holds a sound reference.
spriteid Yes Holds a sprite reference.
state Yes A reference to an actor state.
statelabel Yes The name of an actor state.
textureid Yes Holds a texture reference.
void No Alias for None. Unknown purpose, likely implementation error.
voidptr No A pointer to a real memory address. Implementation detail.

Strings will implicitly convert to sound and statelabel.

Variable Name

Variable names can have an array's size on them, instead of on the type, or none. Variable names are formed as either:

Identifier
Identifier Array-size

Array Size

Array sizes can be multi-dimensional or automatically sized, so all of the following syntaxes are available:

[ ]
[ Expression ] $[Array-size...]$