6.49 Enumerations

8.12

6.49 Enumerations🔗ℹ

definition

...

enum_clause	=	id ...
	\|	~is_a: annot; ...
	\|	~is_a annot

Defines id_name as a predicate annotation and as a namespace, where the namespace exports each id as the symbol #'id and as a binding form that matches the symbol #'id. The annotation is satisfied by each symbol #'id and by values satisfying any of the annots specified with ~is_a.

enum Mouse:
  itchy
  mickey minnie
  jerry

> Mouse.itchy
#'itchy
> #'itchy is_a Mouse
#true
> #'scratchy is_a Mouse
#false
> match #'jerry
| Mouse.itchy: "scratchy"
| Mouse.jerry: "tom"
"tom"

enum Cat:
  ~is_a String
  scratchy
  tom

> Cat.tom is_a Cat
#true
> "Felix" is_a Cat
#true

1	Rhombus Essentials
2	Collections and Iteration
3	Syntax Objects and Macros
4	Classes and Interfaces
5	Static Information and Binding
6	Core Reference
7	Meta and Macros Reference
8	Rhombus Static by Default
9	Libraries
10	Naming Conventions

6.1	General Forms
6.2	Definitions
6.3	Namespaces
6.4	Import
6.5	Export
6.6	Functions
6.7	Operators
6.8	Classes and Interfaces
6.9	Veneers
6.10	Mutable Variables and Assignment
6.11	Repetitions
6.12	Block
6.13	Conditionals
6.14	Matching
6.15	Iteration
6.16	Recursion
6.17	Context Parameters
6.18	Exceptions
6.19	Continuations
6.20	Implicit Forms
6.21	Static and Dynamic Lookup
6.22	Modules and Submodules
6.23	Booleans
6.24	Numbers
6.25	Characters
6.26	Strings
6.27	Keywords
6.28	Symbols
6.29	Byte Strings
6.30	Lists
6.31	Pairs and Pair Lists
6.32	Mutable Lists
6.33	Arrays
6.34	Maps
6.35	Sets
6.36	Boxes
6.37	Indexables
6.38	Listables
6.39	Sequences
6.40	Appendables
6.41	Comparables
6.42	Paths
6.43	Source Locations
6.44	Void
6.45	Equality
6.46	Dot
6.47	Multiple Values
6.48	Annotations
6.49	Enumerations
6.50	Input and Output
6.51	Eval
6.52	Syntax Objects
6.53	Syntax Classes
6.54	Simple Expression Macros
6.55	Unit Testing