9.7 Callables

8.15.0.12

9.7 Callables🔗ℹ

interface

Provided only in the class space, not the annot or namespace space.

An interface that a class can implement (publicly or privately) to make instances of the class callable as functions. The interface has one abstract method, which must be overridden to implement the behavior of function calls:

call — receives the arguments that are passed to the instance that is called as a function, and the method’s result is the result of the function call.

class Posn(x, y):
  private implements Callable
  private override method call(dx, dy):
    Posn(x + dx, y + dy)

> def p = Posn(1, 2)
> p
#<function:Posn>
> p(3, 4)
#<function:Posn>

1	Notation and Conventions
2	Implicits and Context
3	Names and Definitions
4	Functions and Operators
5	Comparison and Branching
6	Objects and Annotations
7	Basic Data
8	Collections and Iteration
9	Object Protocols
10	Higher-Order Control
11	Code as Data
12	String Formatting and Matching
13	Input and Output
14	Operating System
15	Threads and Concurrency
16	Runtime System
17	Meta and Macros

9.1	Indexables
9.2	Listables
9.3	Sequences
9.4	Appendables
9.5	Comparables
9.6	Printables
9.7	Callables
9.8	Closeables
9.9	Serializables