Map, SharedMap, WeakMap

Argentum standard library has three hash maps: Map, SharedMap, WeakMap.

Most of design details of Maps are similar to Arrays:

• They are not built in the language.
• On indexation they return optional type, indicating if element exists in the map.
• Their semantics reflects one of pointers.
• They are of variable size and initially empty.
• They can be frozen and turned into shared-immutable.

These maps are unordered key-value containers, where:

• keys are always shared immutable objects
• values are own, shared or weak pointers respectively.

Internally they are implemented as flat, open addressed, 2ⁿ grow, linear probe, robin hood hashing maps.

using sys { Map }

class Pt{
   x = 0; y = 0;
   call(ax, int, ay int) this { x:= ax; y := ay }
}

m = Map(String, Pt)
   ("Alpha", Pt(1, 2))
   ("Bravo", Pt(-1, 42));
log(m["Aplha"]
   ? "Pt({_.x}, {_.y})"
   : "Not found"); 
// It prints Pt(1, 2)

Why keys are always immutable

TBD

User types as keys

TBD