# [−][src]Trait alga::general::SupersetOf

Nested sets and conversions between them. Useful to work with substructures. It is preferable
to implement the `SupersetOf`

trait instead of `SubsetOf`

whenever possible (because
`SupersetOf`

is automatically implemented whenever `SubsetOf`

is.

The notion of "nested sets" is very broad and applies to what the types are *supposed to
represent*, independently from their actual implementation details and limitations. For
example:

- f32 and f64 are both supposed to represent reals and are thus considered equal (even if in practice f64 has more elements).
- u32 and i8 are respectively supposed to represent natural and relative numbers. Thus, i8 is a superset of u32.
- A quaternion and a 3x3 orthogonal matrix with unit determinant are both sets of rotations. They can thus be considered equal.

In other words, implementation details due to machine limitations are ignored (otherwise we could not even, e.g., convert a u64 to an i64). If considering those limitations are important, other crates allowing you to query the limitations of given types should be used.

## Required methods

`fn is_in_subset(&self) -> bool`

Checks if `self`

is actually part of its subset `T`

(and can be converted to it).

`unsafe fn to_subset_unchecked(&self) -> T`

Use with care! Same as `self.to_subset`

but without any property checks. Always succeeds.

`fn from_subset(element: &T) -> Self`

The inclusion map: converts `self`

to the equivalent element of its superset.

## Provided methods

`fn to_subset(&self) -> Option<T>`

The inverse inclusion map: attempts to construct `self`

from the equivalent element of its
superset.

Must return `None`

if `element`

has no equivalent in `Self`

.