Class: Symbol

Inherits:
Object show all
Defined in:
object.c,
object.c

Overview

********************************************************************

<code>Symbol</code> objects represent names and some strings
inside the Ruby
interpreter. They are generated using the <code>:name</code> and
<code>:"string"</code> literals
syntax, and by the various <code>to_sym</code> methods. The same
<code>Symbol</code> object will be created for a given name or string
for the duration of a program's execution, regardless of the context
or meaning of that name. Thus if <code>Fred</code> is a constant in
one context, a method in another, and a class in a third, the
<code>Symbol</code> <code>:Fred</code> will be the same object in
all three contexts.

   module One
     class Fred
     end
     $f1 = :Fred
   end
   module Two
     Fred = 1
     $f2 = :Fred
   end
   def Fred()
   end
   $f3 = :Fred
   $f1.id   #=> 2514190
   $f2.id   #=> 2514190
   $f3.id   #=> 2514190

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.all_symbols ⇒ Object

Instance Method Details

#==(other) ⇒ Boolean #equal?(other) ⇒ Boolean #eql?(other) ⇒ Boolean

Equality—At the Object level, == returns true only if obj and other are the same object. Typically, this method is overridden in descendent classes to provide class-specific meaning.

Unlike ==, the equal? method should never be overridden by subclasses: it is used to determine object identity (that is, a.equal?(b) iff a is the same object as b).

The eql? method returns true if

<i>obj</i> and <i>anObject</i> have the

same value. Used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition, but there are exceptions. Numeric types, for example, perform type conversion across ==, but not across eql?, so:

1 == 1.0     #=> true
1.eql? 1.0   #=> false

Overloads:

  • #==(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #equal?(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #eql?(other) ⇒ Boolean

    Returns:

    • (Boolean) 


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# File 'object.c', line 93

static VALUE
rb_obj_equal(obj1, obj2)
VALUE obj1, obj2;

#id2name ⇒ String #to_s ⇒ String

Returns the name or string corresponding to sym.

:fred.id2name   #=> "fred"

Overloads:



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1191
 
# File 'object.c', line 1189

static VALUE
sym_to_s(sym)
VALUE sym;

#inspect ⇒ String

Returns the representation of sym as a symbol literal.

:fred.inspect   #=> ":fred"

Returns:



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# File 'object.c', line 1158

static VALUE
sym_inspect(sym)
VALUE sym;

#to_i ⇒ Fixnum

Returns an integer that is unique for each symbol within a particular execution of a program.

:fred.to_i           #=> 9809
"fred".to_sym.to_i   #=> 9809

Returns:



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# File 'object.c', line 1128

static VALUE
sym_to_i(sym)
VALUE sym;

#to_int ⇒ Object

:nodoc:



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# File 'object.c', line 1140

static VALUE
sym_to_int(sym)
VALUE sym;

#to_proc ⇒ Object

Returns a Proc object which respond to the given method by sym.

(1..3).collect(&:to_s)  #=> ["1", "2", "3"]



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# File 'object.c', line 1238

static VALUE
sym_to_proc(VALUE sym)
{
    return rb_proc_new(sym_call, (VALUE)SYM2ID(sym));
}

#id2name ⇒ String #to_s ⇒ String

Returns the name or string corresponding to sym.

:fred.id2name   #=> "fred"

Overloads:



1189
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# File 'object.c', line 1189

static VALUE
sym_to_s(sym)
VALUE sym;

#to_sym ⇒ Object

In general, to_sym returns the Symbol corresponding to an object. As sym is already a symbol, self is returned in this case.



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# File 'object.c', line 1206

static VALUE
sym_to_sym(sym)
VALUE sym;