trait val PrefixSpec
"""
Base trait for all prefix specifiers.
"""
primitive PrefixDefault is PrefixSpec
"""
No prefix before the formatted value.
"""
primitive PrefixSpace is PrefixSpec
"""
Use a space as the prefix for positive numbers.
"""
primitive PrefixSign is PrefixSpec
"""
Use a `+` sign as the prefix for positive numbers.
"""
type PrefixNumber is
( PrefixDefault
| PrefixSpace
| PrefixSign )