On this page:
object?
class?
interface?
generic?
object=?
object->vector
class->interface
object-interface
is-a?
subclass?
implementation?
interface-extension?
method-in-interface?
interface->method-names
object-method-arity-includes?
field-names
object-info
class-info
exn: fail: object
Version: 4.2.1

5.11 Object, Class, and Interface Utilities

(object? v)  boolean?
  v : any/c
Returns #t if v is an object, #f otherwise.

(class? v)  boolean?
  v : any/c
Returns #t if v is a class, #f otherwise.

(interface? v)  boolean?
  v : any/c
Returns #t if v is an interface, #f otherwise.

(generic? v)  boolean?
  v : any/c
Returns #t if v is a generic, #f otherwise.

(object=? a b)  boolean?
  a : object?
  b : object?
Determines if two objects are the same object, or not; this procedure uses eq?, but also works properly with contracts.

(object->vector object [opaque-v])  vector?
  object : object?
  opaque-v : any/c = #f
Returns a vector representing object that shows its inspectable fields, analogous to struct->vector.

(class->interface class)  interface?
  class : class?
Returns the interface implicitly defined by class.

(object-interface object)  interface?
  object : object?
Returns the interface implicitly defined by the class of object.

(is-a? v type)  boolean?
  v : any/c
  type : (or/c interface? class?)
Returns #t if v is an instance of a class type or a class that implements an interface type, #f otherwise.

(subclass? v class)  boolean?
  v : any/c
  class : class?
Returns #t if v is a class derived from (or equal to) class, #f otherwise.

(implementation? v interface)  boolean?
  v : any/c
  interface : interface?
Returns #t if v is a class that implements interface, #f otherwise.

(interface-extension? v interface)  boolean?
  v : any/c
  interface : interface?
Returns #t if v is an interface that extends interface, #f otherwise.

(method-in-interface? sym interface)  boolean?
  sym : symbol?
  interface : interface?
Returns #t if interface (or any of its ancestor interfaces) includes a member with the name sym, #f otherwise.

(interface->method-names interface)  (listof symbol?)
  interface : interface?
Returns a list of symbols for the method names in interface, including methods inherited from superinterfaces, but not including methods whose names are local (i.e., declared with define-local-member-names).

(object-method-arity-includes? object    
  sym    
  cnt)  boolean?
  object : object?
  sym : symbol?
  cnt : exact-nonnegative-integer?
Returns #t if object has a method named sym that accepts cnt arguments, #f otherwise.

(field-names object)  (listof symbol?)
  object : object?
Returns a list of all of the names of the fields bound in object, including fields inherited from superinterfaces, but not including fields whose names are local (i.e., declared with define-local-member-names).

(object-info object)  
(or/c class? #f) boolean?
  object : any/c
Returns two values, analogous to the return values of struct-info:
  • class: a class or #f; the result is #f if the current inspector does not control any class for which the object is an instance.

  • skipped?: #f if the first result corresponds to the most specific class of object, #t otherwise.

Returns seven values, analogous to the return values of struct-type-info:

Raised for class-related failures, such as attempting to call a method that is not supplied by an object.