sym_03.rb

Symbol.all_symbols.length                      # => 3893
Symbol.all_symbols.grep(/Struct/)              # => [:Struct]

:dummy_symbol
Symbol.all_symbols.length                      # => 3894
Symbol.all_symbols.grep(/dummy_symbol/)        # => [:dummy_symbol]

dummy_variable = nil
Symbol.all_symbols.length                      # => 3895
Symbol.all_symbols.grep(/dummy_variable/)      # => [:dummy_variable]

def dummy_method; end
Symbol.all_symbols.length                      # => 3896
Symbol.all_symbols.grep(/dummy_method/)        # => [:dummy_method]

class DummyClass; end
Symbol.all_symbols.length                      # => 3897
Symbol.all_symbols.grep(/DummyClass/)          # => [:DummyClass]

Symbol.all_symbols.grep(/Hash/)                # => [:Hash]
class Hash; end
Symbol.all_symbols.length                      # => 3897