Defining a custom hash function for structures

vec2_hash.ooc

import structs/HashMap

Vec2: cover {
	x, y:Int
}

vec2equals: func <T> (_a, _b:T) -> Bool {
	a := _a as Vec2
	b := _b as Vec2
	a x == b x && a y == b y
}

vec2hash: func <T> (_a:T) -> SizeT {
	a := _a as Vec2
	a x * 31 + a y
}

main: func {
	map := HashMap<Vec2, String> new()
	
	map hashKey = vec2hash
	map keyEquals = vec2equals
	
	a := (10, 20) as Vec2
	b := (10, 20) as Vec2
	
	map put(a, "foo")
	map get(b) println()
}