SPVM::Document::Language::Types - Types in the SPVM Language

Name

SPVM::Document::Language::Types − Types in the SPVM Language

Description

This document describes types in the SPVM language.

Data

This section describes data.

A data is called value.

Number

The value of numeric types is called number.

Normally, numbers are created by numeric literals.

# byte − 8bit signed integer
my $number = (byte)1;
# short − 16bit signed integer
my $number = (short)1;
# int − 32bit signed integer
my $number = 1;
# long − 64bit signed integer
my $number = 1L;
# float − 32bit floating point
my $number = 1.5f;
# double − 64bit floating point
my $number = 1.0;

A character created by character literal is a number of byte type.

# A number of byte type created by a character literal
my $char = 'a';

See the following section operations for numbers.

	•		Numeric Operators
	•		Numeric Comparison Operators

Internal Representation of Negative Integers

Negative integers are represented by two's complement <https://en.wikipedia.org/wiki/Two%27s_complement>.

String

The value of string type is called string.

A string consists of characters of the "byte" type.

A string has its length.

A string is an object.

Normally, a string is created by a string literal or new_string_len operator.

# A string created by a string literal
my $string = "Hello";
my $char = $string−>[0];
# A mutable string created by new_string_len operator
my $string = new_string_len 3;
$string−>[0] = 'a';

See the following sections about operations for strings.

	•		length Operator
	•		String Concatenation Operator
	•		Character Get Operation
	•		Character Set Operation
	•		new_string_len Operator
	•		make_read_only Operator
	•		is_read_only Operator
	•		String Comparison Operators
	•		copy Operator

Sting Native Level Representation

At native level, the character just after the last character of the string is set to "\0", so the characters in the string can be used as a C language string.

# The characters in the string can be used as a C language string
void* obj_string = stack[0].oval;
const char* chars = env−>get_chars(env, stack, obj_string);
if (strcmp(chars, "Hello") == 0) {
}

Array

The value of an array type is called array.

An array consists of a set of numbers, a set of objects, or a set of multi−numeric numbers.

An array has its length.

The elements of an array are arranged by index and the index starts from 0.

An array is an object.

Normally, an array is created by new Operator and an array initialization.

# An array created by new operator
my $numbers = new int[3];
$numbergers−>[0] = 1;
my $strings = new string[3];
my $objects = new Point[3];
my $mulnum_numbers = new Complex_2d[3];
# An array created by an array initialization
my $numbers = [1, 2, 3];

All elements of an array can be got by for statement.

# for statement
for (my $i = 0; $i < @$numbers; $i++) {
my $number = $numbers−>[$i];
}
# for−each statement
for my $number (@$numbers) {
}

See the following sections about operations for arrays.

	•		Creating Array in new Operator
	•		Array Initialization
	•		Array Length Operator
	•		Array Element Get Operation
	•		Array Element Set Operation

Object

The value of an object type is called object.

A string is an object.

An array is an object.

An objcet of class type has its fields. A field is a number or an object.

Normally, an object is created by new operator.

# An object created by new operator
my $point = new Point;

When an object is created, memory for the object is allocated in heap memory.

Created objects are destroyed by garbage collection.

See the following sections about operations for objects.

	•		new Operator
	•		dump Operator
	•		Field Get Operation
	•		Field Set Operation
	•		isa Operator
	•		is_type Operator
	•		type_name Operator

Object Native Level Representation

At native level, an object is a memory address.

void* obj_point = stack[0].oval;

Undefined Value

The value of undef type is called undefined value.

An undefined value means the value is undefined.

An undefined value is created by undef operator.

undef

An undefined value is able to be assigned to an object type.

my $point : Point = undef;

Examples:

# Examples of undefined values
my $string : string = undef;
if (undef) {
}
my $message = "Hello";
if ($message == undef) {
}

Undefined Value Native Level Representation

At native level, an undefined value is equal to 0, normally a null pointer "NULL" defined in "stddef.h".

NULL

Multi−Numeric Number

The value of a multi−numeric type is called multi−numeric number.

A multi−numeric number is a set of numbers of the same type.

my $z : Complex_2d;
$z−>{re} = 1;
$z−>{im} = 2;

See the following sections about operations for multi−numeric numbers.

	•		Multi−Numeric Field Get Operation
	•		Multi−Numeric Field Set Operation

Reference

The value of a reference type is called reference.

A reference has a referencing value.

A referencing value must be a number or a multi−numeric number

The reference operator "\" creates a reference.

my $number : int;
my $number_ref = \$number;

See the following sections about operations for multi−numeric numbers.

	•		Referenced Value Get Operation
	•		Referenced Value Set Operation
	•		Reference Operator
	•		Dereference Operator
	•		Referenced Multi−Numeric Field Get Operation
	•		Referenced Multi−Numeric Field Set Operation

Reference Native Level Representation

At native level, a reference is a memory address.

int32_t* num_ref = stack[0].iref;

Types

This section describes types.

Numeric Types

This section describes numeric types.

Integer Types

This section describes integer types.

An interger type is a numeric type.

byte Type

The "byte" type is the type for a signed 8−bit integer.

byte

The "byte" type is an integer type.

short Type

The "short" type is the type for a signed 16−bit integer.

short

The "short" type is an integer type.

int Type

The "int" type is the type for a signed 32−bit integer.

int

The "int" type is an integer type.

long Type

The "long" type is the type for a signed 64−bit integer.

long

The "long" type is an integer type.

Floating Point Types

This section describes floating point types.

A floating point type is a numeric type.

float Type

The "float" type is the type for 32bit floating point.

float

The "float" type is a floating point type.

double Type

The "double" type is the type for 64bit floating point.

double

The "double" type is a floating point type.

Numeric Types Order

numeric types have its order.

The order is "byte", "short", "int", "long", "float", "double" from smallest to largest.

Object Types

This section lists object types.

string Type

The "string" type is the type for strings.

string

The "string" type is an object type.

The "string" type can be qualified with mutable type qualifier.

mutable string

Class Types

A class type is the type for a class.

A class type is defined by class definition.

class CLASS_TYPE {
}

An object can be created from a class by a new operator.

Note that an interface type and a multi−numeric type is not a class type although these types are defined by class definition.

Numeric Object Types

A numeric object type is a class type that owns the corresponding field of a numeric type.

The List of Numeric Object Types:

Interface Types

An interface type is a type for an interface.

An interface type is defined by an interface definition.

class INTERFACE_TYPE : interface_t {
}

Any Object Type

Any object type "object" is the type to which any object type can be assigned.

object

Examples:

# Examples of any object type
my $object: object = new Foo;

Basic Types

A basic type is a type whose type dimension is 0 and that can be an element of an array.

The List of Basic Types:

	•		Numeric types
	•		Multi−numeric types
	•		Class types
	•		Interface types
	•		any object type
	•		string type

undef Type

The undef type is the type of an undefined value.

void Type

The "void" type is the type that represents a method defined by a method definition does not return a return value.

void

Array Types

An array type is a type for an array. An array type consists of a basic type and a type dimension such as "[]", "[][]".

BASIC_TYPE[]..

("[].." means one more "[]")

Examples:

# Numeric array
int[]
double[]
# String array
string []
# Class array
Point[]
# Any object array
object[]
# 2 dimensional array
int[][]
# 3 dimensional array
int[][][]

An array type is an object type.

Compilation Errors:

The dimesion is less than or equal to 255. Otherwise, a compilation error occurs.

Numeric Array Types

A numeric array type is an array type of a numeric type.

The List of Numeric Array Types:

byte[]
short[]
int[]
long[]
float[]
double[]

Object Array Types

An object array type is an array type of an object type.

Examples:

Point[]
Point[][]
Stringable[]
string[]
object[]

String Array Type

The string array type is array type string type.

string[]

Class Array Types

A class array type is an array type of a class type.

Examples:

Int[]
Point[]

Interface Array Types

An interface array type is an array type of an interface type.

Examples:

Stringable[]
Cloneable[]

Multi−Dimensional Array Types

A multi−dimensional array type is an array type of an array type.

Examples:

int[][]
Int[][]
string[][][]
object[][]

A multi−dimensional array is created by the syntax of creating a multi−dimensional array of the "new" operator.

Multi−Numeric Array Types

A multi−numeric array type is an array type of a multi−numeric type.

Examples:

Complex_2d[]
Complex_2f[]

Any Object Array Type

The any object array type "object[]" is array type to which any object array type can be assigned.

object[]

Multi−Numeric Types

A multi−numeric type is a type for a multi−numeric number.

A multi−numeric type is defined by a multi−numeric type definition.

class MULNUM_TYPE : mulnum_t {
}

Reference Types

A reference type is a type for a reference.

TYPE*

A reference type consists of a type followed by "*".

TYPE must be a numeric type or a multi−numeric type.

Numeric Reference Types

A numeric reference type is a reference type of a numeric type.

The List of Numeric Reference Types:

byte*
short*
int*
long*
float*
double*

Multi−Numeric Reference Types

A multi−numeric reference types is a reference type of a multi−numeric type.

MULNUM_TYPE*

Examples:

Complex_2d*
Complex_2f*

Type Qualifiers

A type qualifier qualify a type.

QUALIFIER TYPE

The QUALIFIER qualified the type TYPE.

mutable Type Qualifier

The "mutable" type qualifier qualifies string type.

mutable string;

The string of string type with the "mutable" type qualifier is able to be set a character.

my $string = (mutable string)copy "abc";
$string−>[0] = 'd';

Type Initial Value

The value of a type is initialized by its type initial value.

The List of Type Initial Values:

Type Width

The type width is the length of runtime stack of the type.

If the type is a multi−numeric type, the type width is the length of the fields, owhterwise it is 1.

Union Type

A union type expresses the logical OR of types.

TYPE1|TYPE2|TYPEn

A union type is treated as any object type "object".

Examples:

my $union = (string|string[])undef;
method : foo ($union : string|string[]) {
}

Generic Type

The generic type is

TYPE of ELEMENT_TYPE

TYPE is a type.

ELEMENT_TYPE is a type.

A generic type is treated as "TYPE". "ELEMETN_TYPE" is ignored in compilation time type checks.

"ELEMETN_TYPE" is only used for the type cast for "element" type.

Examples:

# Examples of generic types
has points : List of Point;
has hash_of_list_of_point : Hash of List of Point;
our $POINTS : List of Point;
my $points : List of Point;
static method foo : List of Point ($arg : List of Point) { ... }
my $replace : object of string|Regex::Replacer;

Compilation Errors:

If the type specified as the generic type is not found, a compilation error occurs.

Assignment Requirement

The assignment requirement is the requirement whether one type is able to be assigned to another type.

What does it mean to assign one type to another type?

Typically, it is sufficient to consider a case where a value of a type TYPE_FROM is assigned to a variable of a type TYPE_TO.

my $value : TYPE_FROM;
my $var : TYPE_TO = $value;

Abstracting this, type−to−type assignment is defined.

TYPE_TO = TYPE_FROM

Note that this is a concept, not an actual syntax.

Some assinments perform a data conversion.

In the following description, the word "Type" is omitted when it is obvious.

Assignment Requirement to Numeric

Assignment Requirement from Numeric to Numeric

To Larger:

To Smaller:

"Conditional Yes" means the followings.

For Integral Types:

If the value of TYPE_FROM is represented by an interger literal and between the max and minimal value of the type of TYPE_TO, Yes, otherwize No.

For Floating Point types:

If the value of TYPE_FROM is represented by a floating point literal, Yes, otherwize No.

Assignment Requirement from NumericObject to Numeric

Assignment Requirement from Any Object to Numeric

Assignment Requirement from Other to Numeric

NumericX is a numeric type.

Assignment Requirement to Multi−Numeric

Multi−NumericX is a multi−numeric type.

Assignment Requirement to Referenece

ReferenceX is a reference type.

Assignment Requirement to String

NumericX is a numeric type.

Assignment Requirement to NumericObject

NumericObjectX is a numeric object type.

NumericX is a numeric type.

Assignment Requirement to Class

ClassX is a class type.

SuperClassX is a super class of ClassX.

Assignment Requirement to Interface

InterfaceX is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Assignment Requirement to Any Object

ObjectX is an object type.

NumericX is a numeric type.

Assignment Requirement to undef

X is a type.

Assignment Requirement to void

X is a type.

Assignment Requirement to Numeric Array

NumericX is a numeric type.

Assignment Requirement to Multi−Numeric Array

Multi−NumericX is a multi−numeric type.

Assignment Requirement to String Array

Assignment Requirement to Class Array

ClassX is a class type.

SuperClassX is a super class of ClassX.

Assignment Requirement to Interface Array

InterfaceX is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Assignment Requirement to Any Object Array

ObjectX is an object type.

"[].." is one or more "[]".

Assignment Requirement to Multi−Dimensional Array

X is a type.

"[].." is one or more "[]".

D means its type dimension that is greater than or eausl to 2.

X[]..D is a multi−dimensional array.

ClassX is a class type.

SuperClassX is a super class of ClassX.

InterfaceX is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Cast Requirement

The cast requirement is the requirement whether one type is able to be cast to another type.

What does it mean to cast one type to another type?

Typically, it is sufficient to consider a case where a value of a type TYPE_FROM is casted to TYPE_TO.

my $value : TYPE_FROM;
(TYPE_TO)$value;

Abstracting this, type−to−type cast is defined.

(TYPE_TO)TYPE_FROM

Note that this is a concept, not an actual syntax.

Some type casts perform a data conversion.

Some type casts perform a data check.

In the following description, the word "Type" is omitted when it is obvious.

Cast Requirement to Numeric

Cast Requirement from Numeric to Numeric

To Larger:

To Smaller:

Cast Requirement from NumericObject to Numeric

Cast Requirement from Any Object to Numeric

NumericX is a numeric type.

Cast Requirement from Other to Numeric

NumericX is a numeric type.

Cast Requirement to Multi−Numeric

Multi−NumericX is a multi−numeric type.

Cast Requirement to Referenece

ReferenceX is a reference type.

Cast Requirement to String

NumericX is a numeric type.

Cast Requirement to NumericObject

NumericObjectX is a numeric object type.

NumericX is a numeric type.

Cast Requirement to Class

ClassX is a class type.

SuperClassX is a super class of ClassX.

InterfaceX is a an interface type.

Cast Requirement to Interface

ClassX is a class type.

SuperClassX is a super class of ClassX.

InterfaceX is a an interface type.

InterfaceY is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Cast Requirement to Any Object

ObjectX is an object type.

NumericX is a numeric type.

Cast Requirement to Numeric Array

NumericX is a numeric type.

Cast Requirement to Multi−Numeric Array

Multi−NumericX is a multi−numeric type.

Cast Requirement to String Array

Cast Requirement to Class Array

ClassX is a class type.

SuperClassX is a super class of ClassX.

Cast Requirement to Interface Array

ClassX is a class type.

SuperClassX is a super class of ClassX.

InterfaceX is a an interface type.

InterfaceY is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Cast Requirement to Any Object Array

ObjectX is an object type.

"[].." is one or more "[]".

Cast Requirement to Multi−Dimensional Array

X is a type.

"[].." is one or more "[]".

D means its type dimension that is greater than or eausl to 2.

X[]..D is a multi−dimensional array.

ClassX is a class type.

SuperClassX is a super class of ClassX.

InterfaceX is a an interface type.

InterfaceSatisfiedX is a class type or an interface type that satisfied interface requirement of InterfaceX.

Interface Requirement

The interface requirement is the requirement whether an object type is able to be assigned to an interface type.

INTERFACE_TYPE_TO = OBJECT_TYPE_FROM

This is the same concept as type−to−type assignment explained in Assignment Requirement.

INTERFACE_TYPE_TO must be an interface type.

OBJECT_TYPE_FROM must be a class type or an interface type.

The following check is performed on every instance method of OBJECT_TYPE_FROM.

If an instance method of INTERFACE_TYPE_TO has the "required" method attribute, OBJECT_TYPE_FROM or one of its super classes must have a method with the same name.

If OBJECT_TYPE_FROM or one of its super classes has an instance method(this is named METHOD_FROM) with the same name as an instance method of INTERFACE_TYPE_TO, METHOD_FROM must be an instance method and satisfy interface method requirement.

Interface Method Requirement

The interface method requirement is the requirement whether a method is able to be assigned to an interface method.

INTERFACE_METHOD_TO = METHOD_FROM

This is a concept that converts the type−to−type assignment explained in Assignment Requirement to method−to−method assignment.

INTERFACE_METHOD_TO must be an instance method.

METHOD_FROM must be an instance method.

The length of the arguments of the method of the INTERFACE_METHOD_TO type must be greater than or equal to the length of the required arguments the method of the INSTANT_METHOD_TYPE_FROM type.

The every argument other than at 0 index of the method of the INSTANT_METHOD_TYPE_FROM must satisfy assignment requirement to the argument as the same index of the method of the INTERFACE_METHOD_TO without a data conversion and with interface exactly matched.

The return type of the method of the INSTANT_METHOD_TYPE_FROM must must satisfy assignment requirement to the return type of the method of the INTERFACE_METHOD_TO without a data conversion and with interface exactly matched.

Copyright & License

MIT License

Updated 2026-06-01 - jenkler.se | uex.se

	•		SPVM::Document::Language::Class
	•		SPVM::Document::Language::Operators
	•		SPVM::Document::Language::Statements
	•		SPVM::Document::Language
	•		SPVM::Document