Class: Symbol (Ruby 2.3.4)

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    • string.c

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    Symbol

    Symbol objects represent names and some strings inside the Ruby interpreter. They are generated using the :name and :"string" literals syntax, and by the various to_sym methods. The same Symbol 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 Fred is a constant in one context, a method in another, and a class in a third, the Symbol :Fred 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.object_id   #=> 2514190
    $f2.object_id   #=> 2514190
    $f3.object_id   #=> 2514190
    

    Public Class Methods

    all_symbols => array click to toggle source

    Returns an array of all the symbols currently in Ruby's symbol table.

    Symbol.all_symbols.size    #=> 903
    Symbol.all_symbols[1,20]   #=> [:floor, :ARGV, :Binding, :symlink,
                                    :chown, :EOFError, :$;, :String,
                                    :LOCK_SH, :"setuid?", :$<,
                                    :default_proc, :compact, :extend,
                                    :Tms, :getwd, :$=, :ThreadGroup,
                                    :wait2, :$>]
     
                   VALUE
    rb_sym_all_symbols(void)
    {
        VALUE ary = rb_ary_new2(global_symbols.str_sym->num_entries);
        st_foreach(global_symbols.str_sym, symbols_i, ary);
        return ary;
    }
                

    Public Instance Methods

    symbol <=> other_symbol → -1, 0, +1 or nil click to toggle source

    Compares symbol with other_symbol after calling to_s on each of the symbols. Returns -1, 0, +1 or nil depending on whether symbol is less than, equal to, or greater than other_symbol.

    +nil+ is returned if the two values are incomparable.

    See String#<=> for more information.

     
                   static VALUE
    sym_cmp(VALUE sym, VALUE other)
    {
        if (!SYMBOL_P(other)) {
            return Qnil;
        }
        return rb_str_cmp_m(rb_sym2str(sym), rb_sym2str(other));
    }
                
    sym == obj → true or false click to toggle source

    Equality—If sym and obj are exactly the same symbol, returns true.

     
                   #define sym_equal rb_obj_equal
                
    sym == obj → true or false click to toggle source

    Equality—If sym and obj are exactly the same symbol, returns true.

     
                   #define sym_equal rb_obj_equal
                
    sym =~ obj → fixnum or nil click to toggle source

    Returns sym.to_s =~ obj.

     
                   static VALUE
    sym_match(VALUE sym, VALUE other)
    {
        return rb_str_match(rb_sym2str(sym), other);
    }
                
    sym[idx] → char click to toggle source
    sym[b, n] → string

    Returns sym.to_s[].

     
                   static VALUE
    sym_aref(int argc, VALUE *argv, VALUE sym)
    {
        return rb_str_aref_m(argc, argv, rb_sym2str(sym));
    }
                
    capitalize → symbol click to toggle source

    Same as sym.to_s.capitalize.intern.

     
                   static VALUE
    sym_capitalize(VALUE sym)
    {
        return rb_str_intern(rb_str_capitalize(rb_sym2str(sym)));
    }
                
    casecmp(other) → -1, 0, +1 or nil click to toggle source

    Case-insensitive version of Symbol#<=>.

     
                   static VALUE
    sym_casecmp(VALUE sym, VALUE other)
    {
        if (!SYMBOL_P(other)) {
            return Qnil;
        }
        return rb_str_casecmp(rb_sym2str(sym), rb_sym2str(other));
    }
                
    downcase → symbol click to toggle source

    Same as sym.to_s.downcase.intern.

     
                   static VALUE
    sym_downcase(VALUE sym)
    {
        return rb_str_intern(rb_str_downcase(rb_sym2str(sym)));
    }
                
    empty? → true or false click to toggle source

    Returns that sym is :“” or not.

     
                   static VALUE
    sym_empty(VALUE sym)
    {
        return rb_str_empty(rb_sym2str(sym));
    }
                
    encoding → encoding click to toggle source

    Returns the Encoding object that represents the encoding of sym.

     
                   static VALUE
    sym_encoding(VALUE sym)
    {
        return rb_obj_encoding(rb_sym2str(sym));
    }
                
    id2name → string click to toggle source

    Returns the name or string corresponding to sym.

    :fred.id2name   #=> "fred"
    
     
                   VALUE
    rb_sym_to_s(VALUE sym)
    {
        return str_new_shared(rb_cString, rb_sym2str(sym));
    }
                
    inspect → string click to toggle source

    Returns the representation of sym as a symbol literal.

    :fred.inspect   #=> ":fred"
    
     
                   static VALUE
    sym_inspect(VALUE sym)
    {
        VALUE str = rb_sym2str(sym);
        const char *ptr;
        long len;
        char *dest;
    
        if (!rb_str_symname_p(str)) {
            str = rb_str_inspect(str);
            len = RSTRING_LEN(str);
            rb_str_resize(str, len + 1);
            dest = RSTRING_PTR(str);
            memmove(dest + 1, dest, len);
        }
        else {
            rb_encoding *enc = STR_ENC_GET(str);
            RSTRING_GETMEM(str, ptr, len);
            str = rb_enc_str_new(0, len + 1, enc);
            dest = RSTRING_PTR(str);
            memcpy(dest + 1, ptr, len);
        }
        dest[0] = ':';
        return str;
    }
                
    intern → sym click to toggle source

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

     
                   static VALUE
    sym_to_sym(VALUE sym)
    {
        return sym;
    }
                
    length → integer click to toggle source

    Same as sym.to_s.length.

     
                   static VALUE
    sym_length(VALUE sym)
    {
        return rb_str_length(rb_sym2str(sym));
    }
                
    match(obj) → fixnum or nil click to toggle source

    Returns sym.to_s =~ obj.

     
                   static VALUE
    sym_match(VALUE sym, VALUE other)
    {
        return rb_str_match(rb_sym2str(sym), other);
    }
                
    succ click to toggle source

    Same as sym.to_s.succ.intern.

     
                   static VALUE
    sym_succ(VALUE sym)
    {
        return rb_str_intern(rb_str_succ(rb_sym2str(sym)));
    }
                
    size → integer click to toggle source

    Same as sym.to_s.length.

     
                   static VALUE
    sym_length(VALUE sym)
    {
        return rb_str_length(rb_sym2str(sym));
    }
                
    slice(idx) → char click to toggle source
    slice(b, n) → string

    Returns sym.to_s[].

     
                   static VALUE
    sym_aref(int argc, VALUE *argv, VALUE sym)
    {
        return rb_str_aref_m(argc, argv, rb_sym2str(sym));
    }
                
    succ click to toggle source

    Same as sym.to_s.succ.intern.

     
                   static VALUE
    sym_succ(VALUE sym)
    {
        return rb_str_intern(rb_str_succ(rb_sym2str(sym)));
    }
                
    swapcase → symbol click to toggle source

    Same as sym.to_s.swapcase.intern.

     
                   static VALUE
    sym_swapcase(VALUE sym)
    {
        return rb_str_intern(rb_str_swapcase(rb_sym2str(sym)));
    }
                
    to_proc click to toggle source

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

    (1..3).collect(&:to_s)  #=> ["1", "2", "3"]
    
     
                   VALUE
    rb_sym_to_proc(VALUE sym)
    {
    }
                
    to_s → string click to toggle source

    Returns the name or string corresponding to sym.

    :fred.id2name   #=> "fred"
    
     
                   VALUE
    rb_sym_to_s(VALUE sym)
    {
        return str_new_shared(rb_cString, rb_sym2str(sym));
    }
                
    to_sym → sym click to toggle source

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

     
                   static VALUE
    sym_to_sym(VALUE sym)
    {
        return sym;
    }
                
    upcase → symbol click to toggle source

    Same as sym.to_s.upcase.intern.

     
                   static VALUE
    sym_upcase(VALUE sym)
    {
        return rb_str_intern(rb_str_upcase(rb_sym2str(sym)));
    }