6.28 Symbols

8.12

6.28 Symbols🔗ℹ

A symbol value reflects internal representation of syntax-object identifier content, without the binding or source-location information that is associated with an identifier. A symbol is similar to a string, but symbols are typically interned and they are equal by == only when they are equal by ===. The #' operator can produce a symbol value.

Symbols are comparable, which means that generic operations like < and > work on symbols. Comparsion of two symbols is the same as comparing the string forms of the symbols.

annotation

Symbol

Matches symbols.

expression

expression

repetition

repetition

binding operator

binding operator

As an expression, repetition, or binding, #' produces or matches a symbol or keyword, depending whether #' is followed by an identifier or keyword.

> #'hello
#'hello
> #'hello +& " there"
"hello there"
> #'~skeleton
#'~skeleton

> match #'goodbye
| #'hello: "hi"
| #'goodbye: "bye"
"bye"

function

fun Symbol.from_string(str :: ReadableString)

:: Symbol

function

fun Symbol.uninterned_from_string(str :: ReadableString)

:: Symbol

function

fun Symbol.unreadable_from_string(str :: ReadableString)

:: Symbol

Converts a string to a symbol with the same character content. An uninterned symbol is not equal to any other symbol, even ones with the same character content. An unreadable symbol is only equal to other unreadable symbols with the same character content.

> Symbol.from_string("apple")
#'apple
> Symbol.from_string("apple") == #'apple
#true
> Symbol.uninterned_from_string("apple")
#'apple
> Symbol.uninterned_from_string("apple")
== Symbol.uninterned_from_string("apple")
#false
> Symbol.unreadable_from_string("apple")
#'apple
> Symbol.unreadable_from_string("apple") == #'apple
#false
> Symbol.unreadable_from_string("apple")
== Symbol.unreadable_from_string("apple")
#true

function

fun Symbol.gen() :: Symbol

function

fun Symbol.gen(name :: ReadableString || Symbol) :: Symbol

Produces an uninterned symbol with a character content optionally derived from name (typically with digits appended as a debugging aid).

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