# class Crystal::Macros::Arg

- Crystal::Macros::Arg
- Crystal::Macros::ASTNode

##
Overview

A def argument.

##
Defined in:

compiler/crystal/macros.cr

##
Instance Method Summary

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

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

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

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

- #annotations : ArrayLiteral(Annotation)

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

- #default_value : ASTNode | Nop

  Returns the default value of this argument, if any.

- #internal_name : MacroId

  Returns the internal name of this argument.

- #name : MacroId

  Returns the external name of this argument.

- #restriction : ASTNode | Nop

  Returns the type restriction of this argument, if any.

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

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

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

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

def annotations : ArrayLiteral(Annotation) #

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

def default_value : ASTNode | Nop #

Returns the default value of this argument, if any.

def internal_name : MacroId #

Returns the internal name of this argument.

For example, for `def write(to file)` returns `file`.

def name : MacroId #

Returns the external name of this argument.

For example, for `def write(to file)` returns `to`.

def restriction : ASTNode | Nop #

Returns the type restriction of this argument, if any.