### Method argument syntax
Methods can be written with or without parenthesis. Methods can be called with arguments passed in with or without parenthesis, regardless of how the method was defined.

#### Method syntax with parenthesis

```ruby
def full_name(first_name, last_name)
  first_name + " " + last_name
end
```

Calling method with parenthesis:
```
$ puts full_name("Johnny", "Apples")
Johnny Apples
=> nil
```

#### Method syntax without parenthesis

```ruby
def full_name first_name, last_name
  first_name + " " + last_name
end
```

Calling method without parenthesis:
```
$ puts full_name "Johnny", "Apples"
Johnny Apples
=> nil
```

### Method syntax with named arguments

Using named arguments allow you to pass arguments to a method in any order without effecting the result of the method, and it's much more explicit. Can also be used with or without parenthesis.

```ruby
def print_address city:, state:, zip:
  puts city
  puts state
  puts zip
end
```

Calling `print_address` in defined order:
```
$ print_address city: "New York", state: "NY", zip: 10014
New York
NY
10014
=> nil
```

Calling `print_address` in alternate order:
```
$ print_address  zip: 10014, city: "New York",  state: "NY"
New York
NY
10014
=> nil
```

### Method syntax with named arguments and default values
Default values can be used to set a default parameter which can be overridden on method call.

```ruby
def book title:, language: "EN"
  puts title
  puts language
end
```

Calling `book` with a default value:
```
$ book title: "The Mist", language: "EN"
The Mist
EN
=> nil
```

Calling `book` without defining a value:
```
$ book title: "The Mist"
The Mist
EN
=> nil
```

Calling `book` and overriding the default value:
```
$ book title: "The Idiot", language: "RU"
The Idiot
RU
=> nil
```