# class Crystal::Macros::TypeNode

- Crystal::Macros::TypeNode
- Crystal::Macros::ASTNode

##
Overview

Represents a type in the program, like `Int32` or `String`.

##
Defined in:

compiler/crystal/macros.cr

##
Instance Method Summary

- #<(other : TypeNode) : BoolLiteral

  Returns `true` if other is an ancestor of `self`.

- #<=(other : TypeNode) : BoolLiteral

  Returns `true` if `self` is the same as other or if other is an ancestor of `self`.

- #>(other : TypeNode) : BoolLiteral

  Returns `true` if `self` is an ancestor of other.

- #>=(other : TypeNode) : BoolLiteral

  Returns `true` if other is the same as `self` or if `self` is an ancestor of other.

- #[](key : SymbolLiteral | MacroId) : TypeNode | NilLiteral

  Returns the type for the given key in this named tuple type.

- #abstract? : BoolLiteral

  Returns `true` if `self` is abstract, otherwise `false`.

- #all_subclasses : ArrayLiteral(TypeNode)

  Returns all subclasses of this type.

- #ancestors : ArrayLiteral(TypeNode)

  Returns all ancestors of this type.

- #annotation(type : TypeNode) : Annotation | NilLiteral

  Returns the last `Annotation` with the given `type` attached to this type or `NilLiteral` if there are none.

- #annotations(type : TypeNode) : ArrayLiteral(Annotation)

  Returns an array of annotations with the given `type` attached to this type, or an empty `ArrayLiteral` if there are none.

- #annotations : ArrayLiteral(Annotation)

  Returns an array of all annotations attached to this type, or an empty `ArrayLiteral` if there are none.

- #class : TypeNode

  Returns the class of this type.

- #class? : BoolLiteral

  Returns `true` if `self` is a `#class`, otherwise `false`.

- #class_vars : ArrayLiteral(MetaVar)

  Returns the class variables of this type.

- #constant(name : StringLiteral | SymbolLiteral | MacroId) : ASTNode

  Returns a constant defined in this type.

- #constants : ArrayLiteral(MacroId)

  Returns the constants and types defined by this type.

- #has_constant?(name : StringLiteral | SymbolLiteral) : BoolLiteral

  Returns `true` if this type has a constant.

- #has_method?(name : StringLiteral | SymbolLiteral) : BoolLiteral

  Returns `true` if this type has a method.

- #includers : ArrayLiteral(TypeNode)

  Returns all the types `self` is directly included in.

- #instance : TypeNode

  Returns the instance type of this type, if it's a class type, or `self` otherwise.

- #instance_vars : ArrayLiteral(MetaVar)

  Returns the instance variables of this type.

- #keys : ArrayLiteral(MacroId)

  Returns the keys in this named tuple type.

- #methods : ArrayLiteral(Def)

  Returns the instance methods defined by this type, without including inherited methods.

- #module? : BoolLiteral

  Returns `true` if `self` is a `module`, otherwise `false`.

- #name(*, generic_args : BoolLiteral = true) : MacroId

  Returns the fully qualified name of this type.

- #nilable? : BoolLiteral

  Returns `true` if `nil` is an instance of `self`, otherwise `false`.

- #overrides?(type : TypeNode, method : StringLiteral | SymbolLiteral | MacroId) : Bool

  Determines if `self` overrides any method named method from type type.

- #resolve : TypeNode

  Returns `self`.

- #resolve? : TypeNode

  Returns `self`.

- #size : NumberLiteral

  Returns the number of elements in this tuple type or tuple metaclass type.

- #struct? : BoolLiteral

  Returns `true` if `self` is a `struct`, otherwise `false`.

- #subclasses : ArrayLiteral(TypeNode)

  Returns the direct subclasses of this type.

- #superclass : TypeNode | NilLiteral

  Returns the direct superclass of this type.

- #type_vars : ArrayLiteral(TypeNode)

  Returns the type variables of the generic type.

- #union? : BoolLiteral

  Returns `true` if `self` is a union type, otherwise `false`.

- #union_types : ArrayLiteral(TypeNode)

  Returns the types forming a union type, if this is a union type.

### Instance methods inherited from class `Crystal::Macros::ASTNode`

!=(other : ASTNode) : BoolLiteral !=, ==(other : ASTNode) : BoolLiteral ==, class_name : StringLiteral class_name, column_number : StringLiteral | NilLiteral column_number, doc : StringLiteral doc, doc_comment : MacroId doc_comment, end_column_number : StringLiteral | NilLiteral end_column_number, end_line_number : StringLiteral | NilLiteral end_line_number, filename : StringLiteral | NilLiteral filename, id : MacroId id, is_a?(type : TypeNode) : BoolLiteral is_a?, line_number : StringLiteral | NilLiteral line_number, nil? : BoolLiteral nil?, raise(message) : NoReturn raise, stringify : StringLiteral stringify, symbolize : SymbolLiteral symbolize, warning(message : StringLiteral) : NilLiteral warning

##
Instance Method Detail

def <(other : TypeNode) : BoolLiteral #

Returns `true` if other is an ancestor of `self`.

def <=(other : TypeNode) : BoolLiteral #

Returns `true` if `self` is the same as other or if other is an ancestor of `self`.

def >(other : TypeNode) : BoolLiteral #

Returns `true` if `self` is an ancestor of other.

def >=(other : TypeNode) : BoolLiteral #

Returns `true` if other is the same as `self` or if `self` is an ancestor of other.

def [](key : SymbolLiteral | MacroId) : TypeNode | NilLiteral #

Returns the type for the given key in this named tuple type. Gives a compile error if this is not a named tuple type.

def abstract? : BoolLiteral #

Returns `true` if `self` is abstract, otherwise `false`.

    module One; end

    abstract struct Two; end

    class Three; end

    abstract class Four; end

    {{One.abstract?}}   # => false
    {{Two.abstract?}}   # => true
    {{Three.abstract?}} # => false
    {{Four.abstract?}}  # => true

def all_subclasses : ArrayLiteral(TypeNode) #

Returns all subclasses of this type.

def ancestors : ArrayLiteral(TypeNode) #

Returns all ancestors of this type.

def annotation(type : TypeNode) : Annotation | NilLiteral #

Returns the last `Annotation` with the given `type` attached to this type or `NilLiteral` if there are none.

def annotations(type : TypeNode) : ArrayLiteral(Annotation) #

Returns an array of annotations with the given `type` attached to this type, or an empty `ArrayLiteral` if there are none.

def annotations : ArrayLiteral(Annotation) #

Returns an array of all annotations attached to this type, or an empty `ArrayLiteral` if there are none.

def class : TypeNode #

Returns the class of this type. With this you can, for example, obtain class methods by invoking `type.class.methods`.

def class? : BoolLiteral #

Returns `true` if `self` is a `#class`, otherwise `false`.

    module One; end

    class Two; end

    struct Three; end

    {{One.class?}}   # => false
    {{Two.class?}}   # => true
    {{Three.class?}} # => false

def class_vars : ArrayLiteral(MetaVar) #

Returns the class variables of this type.

def constant(name : StringLiteral | SymbolLiteral | MacroId) : ASTNode #

Returns a constant defined in this type.

If the constant is a constant (like `A = 1`), then its value as an `ASTNode` is returned. If the constant is a type, the type is returned as a `TypeNode`. Otherwise, `NilLiteral` is returned.

def constants : ArrayLiteral(MacroId) #

Returns the constants and types defined by this type.

def has_constant?(name : StringLiteral | SymbolLiteral) : BoolLiteral #

Returns `true` if this type has a constant. For example `DEFAULT_OPTIONS` (the name you pass to this method is `"DEFAULT_OPTIONS"` or `:DEFAULT_OPTIONS` in this cases).

def has_method?(name : StringLiteral | SymbolLiteral) : BoolLiteral #

Returns `true` if this type has a method. For example `default_options` (the name you pass to this method is `"default_options"` or `:default_options` in this cases).

def includers : ArrayLiteral(TypeNode) #

Returns all the types `self` is directly included in.

def instance : TypeNode #

Returns the instance type of this type, if it's a class type, or `self` otherwise. This is the opposite of `#class`.

def instance_vars : ArrayLiteral(MetaVar) #

Returns the instance variables of this type. Can only be called from within methods (not top-level code), otherwise will return an empty list.

def keys : ArrayLiteral(MacroId) #

Returns the keys in this named tuple type. Gives a compile error if this is not a named tuple type.

def methods : ArrayLiteral(Def) #

Returns the instance methods defined by this type, without including inherited methods.

def module? : BoolLiteral #

Returns `true` if `self` is a `module`, otherwise `false`.

    module One; end

    class Two; end

    struct Three; end

    {{One.module?}}   # => true
    {{Two.module?}}   # => false
    {{Three.module?}} # => false

def name(*, generic_args : BoolLiteral = true) : MacroId #

Returns the fully qualified name of this type. Optionally without generic_args if `self` is a generic type; see `#type_vars`.

    class Foo(T); end

    module Bar::Baz; end

    {{Bar::Baz.name}}                 # => Bar::Baz
    {{Foo.name}}                      # => Foo(T)
    {{Foo.name(generic_args: false)}} # => Foo

def nilable? : BoolLiteral #

Returns `true` if `nil` is an instance of `self`, otherwise `false`.

    {{String.nilable?}}                   # => false
    {{String?.nilable?}}                  # => true
    {{Union(String, Bool, Nil).nilable?}} # => true
    {{NoReturn.nilable?}}                 # => false
    {{Value.nilable?}}                    # => true

def overrides?(type : TypeNode, method : StringLiteral | SymbolLiteral | MacroId) : Bool #

Determines if `self` overrides any method named method from type type.

    class Foo
      def one
        1
      end

      def two
        2
      end
    end

    class Bar < Foo
      def one
        11
      end
    end

    {{ Bar.overrides?(Foo, "one") }} # => true
    {{ Bar.overrides?(Foo, "two") }} # => false

def resolve : TypeNode #

Returns `self`. This method exists so you can safely call `#resolve` on a node and resolve it to a type, even if it's a type already.

def resolve? : TypeNode #

Returns `self`. This method exists so you can safely call `#resolve` on a node and resolve it to a type, even if it's a type already.

def size : NumberLiteral #

Returns the number of elements in this tuple type or tuple metaclass type. Gives a compile error if this is not one of those types.

def struct? : BoolLiteral #

Returns `true` if `self` is a `struct`, otherwise `false`.

    module One; end

    class Two; end

    struct Three; end

    {{One.struct?}}   # => false
    {{Two.struct?}}   # => false
    {{Three.struct?}} # => true

def subclasses : ArrayLiteral(TypeNode) #

Returns the direct subclasses of this type.

def superclass : TypeNode | NilLiteral #

Returns the direct superclass of this type.

def type_vars : ArrayLiteral(TypeNode) #

Returns the type variables of the generic type. If the type is not generic, an empty array is returned.

def union? : BoolLiteral #

Returns `true` if `self` is a union type, otherwise `false`.

See also: `#union_types`.

    {{String.union?}}              # => false
    {{String?.union?}}             # => true
    {{Union(String, Bool).union?}} # => true

def union_types : ArrayLiteral(TypeNode) #

Returns the types forming a union type, if this is a union type. Otherwise returns this single type inside an array literal (so you can safely call `#union_types` on any type and treat all types uniformly).

See also: `#union?`.