Fantom

 

const class

sys::Type

sys::Obj
  sys::Type

Type defines the contract of an Obj by the slots its supports. Types model the inheritance relationships and provide a mapping for all the slots both inherited and declared.

Slots

baseSource

Type? base()

The direct super class of this type (null for Obj). Return sys::Obj for all mixin types.

Examples:

Obj#.base        =>  null
Int#.base        =>  sys::Num
OutStream#.base  =>  sys::Obj
docSource

Str? doc()

Return the raw fandoc for this type or null if not available. If there is additional documentation meta-data available it is included an the start of the string as a series of "@name=value" lines.

emptyListSource

Obj[] emptyList()

Return an immutable empty list of this type. Since immutable lists can be used safely everywhere, this allows signficant memory savings instead allocating new empty lists.

Examples:

Str#.emptyList  =>  Str[,]
facetSource

Facet? facet(Type type, Bool checked := true)

Get a facet by its type. If not found on this type then return null or throw UnknownFacetErr based on check flag. See Facets Doc for details.

facetsSource

Facet[] facets()

Get the list of facets defined on this type or return an empty list if no facets are defined. If looking up a facet by type, then use the facet method which will provide better performance. See Facets Doc for details.

fieldSource

Field? field(Str name, Bool checked := true)

Convenience for (Field)slot(name, checked)

fieldsSource

Field[] fields()

List of the all defined fields (including inherited fields).

findSource

static Type? find(Str qname, Bool checked := true)

Find a Type by it's qualified name "pod::Type". If the type doesn't exist and checked is false then return null, otherwise throw UnknownTypeErr.

fitsSource

Bool fits(Type t)

Does this type implement the specified type. If true, then this type is assignable to the specified type (although the converse is not necessarily true). This method provides the same semantics as the is operator, but between two types rather than an instance and a type. All types (including mixin types) fit sys::Obj.

Example:

Float#.fits(Float#) =>  true
Float#.fits(Num#)   =>  true
Float#.fits(Obj#)   =>  true
Float#.fits(Str#)   =>  false
Obj#.fits(Float#)   =>  false
hasFacetSource

Bool hasFacet(Type type)

Return if this type has the specified facet defined.

inheritanceSource

Type[] inheritance()

Return a recursive flattened list of all the types this type inherits from. The result list always includes this type itself. The result of this method represents the complete list of types implemented by this type - instances of this type are assignable to any type in this list. All types (including mixins) will include sys::Obj in this list.

Examples:

Obj#.inheritance  =>  [sys::Obj]
Int#.inheritance  =>  [sys::Int, sys::Num, sys::Obj]
isAbstractSource

Bool isAbstract()

Return if this Type is abstract and cannot be instantiated. This method will always return true if the type is a mixin.

isClassSource

Bool isClass()

Return if this Type is a class (as opposed to enum or mixin)

isConstSource

Bool isConst()

Return if this is a const class which means instances of this class are immutable.

isEnumSource

Bool isEnum()

Return if this Type is an Enum type.

isFacetSource

Bool isFacet()

Return if this Type is an Facet type.

isFinalSource

Bool isFinal()

Return if this Type is marked final which means it may not be subclassed.

isGenericSource

Bool isGeneric()

A generic type contains slot signatures which may be parameterized - for example Map's key and value types are generic as K and V. Fantom supports three built-in generic types: List, Map, and Func. A parameterized type such as Str[] is not a generic type (all of its generic parameters have been filled in). User defined generic types are not supported in Fantom.

Examples:

Str#.isGeneric   => false
List#.isGeneric  => true
Str[]#.isGeneric => false
isInternalSource

Bool isInternal()

Return if this Type has internal protection scope.

isMixinSource

Bool isMixin()

Return if this Type is a mixin type and cannot be instantiated.

isNullableSource

Bool isNullable()

Is this a nullable type. Nullable types can store the null value, but non-nullables are never null. Null types are indicated with a trailing "?".

isPublicSource

Bool isPublic()

Return if this Type has public protection scope.

isSyntheticSource

Bool isSynthetic()

Return if this Type was generated by the compiler.

isValSource

Bool isVal()

Is this a value type. Fantom supports three implicit value types: Bool, Int, and Float.

makeSource

Obj make(Obj[]? args := null)

Create a new instance of this Type using the following rules:

  1. Call public constructor make with specified arguments
  2. If no public constructor called make or invalid number of of required arguments, then return value of defVal slot (must be static field or static method with zero params)
  3. If no public defVal field, then throw Err
methodSource

Method? method(Str name, Bool checked := true)

Convenience for (Method)slot(name, checked)

methodsSource

Method[] methods()

List of the all defined methods (including inherited methods).

mixinsSource

Type[] mixins()

Return the mixins directly implemented by this type.

Examples:

Obj#.mixins        =>  [,]
Buf#.mixins        =>  [sys::InStream, sys::OutStream]
OutStream#.mixins  =>  [,]
nameSource

Str name()

Simple name of the type such as "Str". For parameterized types derived from List, Map, or Func, this method always returns "List", "Map", or "Func" respectively.

Examples:

Str#.name         => "Str"
acme::Foo#.name   => "Foo"
acme::Foo[]#.name => "List"
ofSource

static Type of(Obj obj)

Get the class Type of the given instance. Also see Obj.typeof which provides the same functionality.

parameterizeSource

Type parameterize(Str:Type params)

If this is a generic type, then dynamically create a new parameterized type with the specified name to type map. If this type is not generic then throw UnsupportedErr. Throw ArgErr if params fails to specify the required parameters:

List => V required
Map  => K, V required
Func => R required, A-H optional

Examples:

List#.parameterize(["V":Bool#]) => Bool[]
Map#.parameterize(["K":Str#, "V":Obj#]) => Str:Obj
paramsSource

Str:Type params()

If this is a parameterized type, then return the map of names to types. If this is not a parameterized type return an empty map.

Examples:

Str#.params => [:]
Str[]#.params => ["V":Str, "L":Str[]]
Int:Slot#.params => ["K":Int, "V":Slot, "M":Int:Slot]
|Int x, Float y->Bool|#.params => ["A":Int, "B":Float, "R":Bool]
podSource

Pod? pod()

Parent pod which defines this type. For parameterized types derived from List, Map, or Func, this method always returns the sys pod.

Examples:

Str#.pod         => sys
acme::Foo#.pod   => acme
acme::Foo[]#.pod => sys
qnameSource

Str qname()

Qualified name formatted as "pod::name". For parameterized types derived from List, Map, or Func, this method always returns "sys::List", "sys::Map", or "sys::Func" respectively. If this a nullable type, the qname does not include the "?".

Examples:

Str#.qname         => "sys::Str"
Str?#.qname        => "sys::Str"
acme::Foo#.qname   => "acme::Foo"
acme::Foo[]#.qname => "sys::List"
signatureSource

Str signature()

Return the formal signature of this type. In the case of non-parameterized types the signature is the same as qname. For parameterized types derived from List, Map, or Func the signature uses the following special syntax:

List => V[]
Map  => [K:V]
Func => |A,B...->R|

If this is a nullable type, the signature ends with "?" such as "sys::Int?".

Examples:

Str#.signature => "sys::Str"
Str?#.signature => "sys::Str?"
Int[]#.signature => "sys::Int[]"
Int:Str#.signature => "[sys::Int:sys::Str]"
Str:Buf[]#.signature => [sys::Str:sys::Buf[]]
|Float x->Bool|#.signature => "|sys::Float->sys::Bool|"
|Float x, Int y|#.signature => |sys::Float,sys::Int->sys::Void|
slotSource

Slot? slot(Str name, Bool checked := true)

Lookup a slot by name. If the slot doesn't exist and checked is false then return null, otherwise throw UnknownSlotErr.

slotsSource

Slot[] slots()

List of the all defined slots, both fields and methods (including inherited slots).

toListOfSource

Type toListOf()

Convenience for List#.parameterize(["V":this])

Examples:

Int#.toListOf => Int[]
Str[]#.toListOf => Str[][]
toLocaleSource

Str toLocale()

Return signature. This method is used to enable toLocale to be used with duck typing across most built-in types. Note: we may change the specification of this method in the future to allow localized type names.

toNonNullableSource

Type toNonNullable()

Return this type as a non-nullable type. If this type is already non-nullable then return this.

toNullableSource

Type toNullable()

Return this type as a nullable type. If this type is already nullable then return this.

toStrSource

override Str toStr()

Overrides sys::Obj.toStr

Always return signature().