The glue that holds ARF syntax together is the argument. It is a syntactical
element that carries a value of any of these types:
- Unsigned integer literal
- Signed integer literal
- Float literal
- String literal
- Rune literal
- Identifier
- Variable definition
- Phrase with one return value
Any slot in ARF that takes a value is an argument, and can carry these things
inside of it. The only exception to this is array length initialization, which
must be an unsigned integer literal.