new Ruby 3 language features

ruby_3.0.1.rb

## "Pattern matching (for use in case/switch statements) 
##  is a feature allowing deep matching of structured values"

# version 2.6.5
> {chicago: :cubs, stlouis: :cardinals, denver: :rockies} => {stlouis:} #=> SyntaxError
> 1 in 1 #=> SyntaxError
> 0 in 1 #=> SyntaxError

# version 3.0.1
> {chicago: :cubs, stlouis: :cardinals, denver: :rockies} => {stlouis:}
> stlouis #=> :cardinals
> 1 in 1  #=> true
> 0 in 1  #=> false

## Hash#except (this Hash method was monkey-patched in Rails, now its built into Ruby)

# version 2.6.5
> {foo: 3, bar: 4, baz: 5}.except(:bar) #=> NoMethodError

# version 3.0.1
> {foo: 3, bar: 4, baz: 5}.except(:bar) #=> {:foo=>3, :baz=>5}

## "Endless" method definition

# version 2.6.5
> def power(base, exponent) = base ** exponent #=> SyntaxError
  
# version 3.0.1
> def power(base, exponent) = base ** exponent #=> :power
> power(2,4) #=> 16