func main():
	>> t := {"one":1, "two":2}
	= {"one":1, "two":2}

	>> t:get("one", 999)
	= 1
	>> t:get("two", 999)
	= 2
	>> t:get("???", 999)
	= 999

	t_str := ""
	for k,v in t:
		t_str ++= "({k}:{v})"
	>> t_str
	= "(one:1)(two:2)"

	>> #t
	= 2
	>> t.fallback
	= !{Text:Int}

	>> t.keys
	= ["one", "two"]
	>> t.values
	= [1, 2]

	>> t2 := {"three":3; fallback=t}
	= {"three":3; fallback={"one":1, "two":2}}

	>> t2:get("one", 999)
	= 1
	>> t2:get("three", 999)
	= 3
	>> t2:get("???", 999)
	= 999

	>> #t2
	= 1
	>> t2.fallback
	= @%{"one":1, "two":2}?

	t2_str := ""
	for k,v in t2:
		t2_str ++= "({k}:{v})"
	>> t2_str
	= "(three:3)"

	>> {i:10*i for i in 5}
	= {1:10, 2:20, 3:30, 4:40, 5:50}
	>> {i:10*i for i in 5 if i mod 2 != 0}
	= {1:10, 3:30, 5:50}
	>> {x:10*x for x in y if x > 1 for y in [3, 4, 5] if y < 5}
	= {2:20, 3:30, 4:40}

	>> t3 := {1:10, 2:20, 3:30}
	>> t3:remove(3)
	>> t3
	= {1:10, 2:20}

	do:
		>> plain := {1:10, 2:20, 3:30}
		>> plain:get(2)
		= 20
		>> plain:get(2, -999)
		= 20
		>> plain:get(456, -999)
		= -999
		>> plain:has(2)
		= yes
		>> plain:has(456)
		= no

		>> fallback := {4:40; fallback=plain}
		>> fallback:has(1)
		= yes
		>> fallback:get(1, -999)
		= 10