# map_entry · Rell standard library · Chromia Docs (concept)

> hidden type map_ entry<K, V> A supertype of all two-element tuples (K, V) (with named and unnamed fields), where K is an
immutable type, and V may be eithe

Source: https://docs.chromia.com/pages/rell-stdlib/-rell-system-library/root/map_entry/

TYPE

# map\_entry

```signature
hidden type map_entry<K, V>
```

A supertype of all two-element tuples `(K, V)` (with named and unnamed fields), where `K` is an
immutable type, and `V` may be either mutable or immutable. Generally used for iterating over maps and
constructing maps from iterables.

Since 0.13.2

[View this page on docs.chromia.com](https://docs.chromia.com/pages/rell-stdlib/-rell%20-system%20-library/%5Broot%5D/map_entry/index.html)Generated API reference, mirrored from the live docs