struct Symbol
Overview
A symbol is a constant that is identified by a name without you having to give it a numeric value.
:hello
:welcome
:"123"
:"symbol with spaces"
Internally a symbol is represented as an Int32
, so it's very efficient.
You can't dynamically create symbols. When you compile your program, each symbol gets assigned a unique number.
Included Modules
Defined in:
primitives.crsymbol.cr
json/to_json.cr
yaml/to_yaml.cr
Class Method Summary
-
.needs_quotes?(string) : Bool
Determines if a string needs to be quoted to be used for a symbol.
Instance Method Summary
-
#!=(other : Symbol) : Bool
Returns
true
ifself
is not equal to other. -
#<=>(other : Symbol)
Compares symbol with other based on
String#<=>
method. -
#==(other : Symbol) : Bool
Returns
true
ifself
is equal to other. - #clone
-
#hash : Int32
Generates an
Int32
hash value for this symbol. -
#inspect(io : IO)
Returns the symbol literal representation as a string.
-
#to_i : Int32
Returns a unique number for this symbol.
- #to_json(json : JSON::Builder)
-
#to_s(io : IO)
Appends the symbol's name to the passed
IO
. -
#to_s : String
Returns the symbol's name as a String.
- #to_yaml(yaml : YAML::Builder)
Instance methods inherited from module Comparable(Symbol)
<(other : T)
<,
<=(other : T)
<=,
<=>(other : T)
<=>,
==(other : T)
==,
>(other : T)
>,
>=(other : T)
>=
Instance methods inherited from struct Value
==(other)
==,
dup
dup
Instance methods inherited from class Object
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, class class, dup dup, hash hash, inspect(io : IO)
inspect inspect, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s
to_s(io : IO) to_s, to_yaml(io : IO)
to_yaml to_yaml, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as
Constructor methods inherited from class Object
from_json(string_or_io, root : String) : selffrom_json(string_or_io) : self from_json, from_yaml(string_or_io) : self from_yaml
Class Method Detail
Determines if a string needs to be quoted to be used for a symbol.
Symbol.needs_quotes? "string" # => false
Symbol.needs_quotes? "long string" # => true
Instance Method Detail
Compares symbol with other based on String#<=>
method. Returns -1
, 0
or +1
depending on whether symbol is less than, equal to,
or greater than other.
See String#<=>
for more information.
Generates an Int32
hash value for this symbol.
See also: Object#hash
.
Returns the symbol literal representation as a string.
:crystal.inspect # => ":crystal"
Appends the symbol's name to the passed IO
.
:crystal.to_s # => "crystal"
Returns the symbol's name as a String.
:foo.to_s # => "foo"
:"hello world".to_s # => "hello world"