5.4 Equality🔗ℹ

See also Equatables.

The == map configuration can be used with forms like the Map.by constructor or Map.by annotation constructor to specify the default equality and hashing functions for map keys. The Map.by(==) annotation, for example, matches only maps that use the default equality and hashing functions.

> "apple" == "apple"

#true

> [1, 2, 3] == 1

#false

> [1, "apple", {"alice": 97}] == [1, "apple", {"alice": 97}]

#true

> 1 == 1.0

#false

The === map configuration can be used with forms like the Map.by constructor or Map.by annotation constructor to specify key equality with === and a corresponding hashing function.

> #'apple === #'apple

#true

> #'apple === #'banana

#false

These comparisons are specialized like + for arguments with Flonum static information.

> 1 .= 1

#true

> 1 .= 2

#false

> 1.0 .= 1

#true

> 1 .!= 2

#true

> 1 .!= 1.0

#false

> "apple" != "apple"

#false

Mutable and immutable strings, byte vectors, and arrays are considered the same if they have the same elements, even if one is mutable and the other is immutable. However, a mutable map or set is never considered equivalent to an immutable map or set, even if they have the same content.

The is_now map configuration can be used with forms like the Map.by constructor or Map.by annotation constructor to specify key equality with is_now and a corresponding hashing function. Beware, however, that mutating a key after it is mapped will tend to make the map entry inaccessible.