-- Numeric map keys: M n _ — maps with integer keys, no `k=str j` tax.
-- Before MapKey, every map lookup keyed by a loop index had to go through a
-- `k=str j` stringification step (the routing-tsp tax). Now numeric keys are
-- first-class: declare `M n _` and pass numbers straight through.
--
-- Floats floor to i64 at the builtin boundary, matching `at xs i`. Text and
-- number keys are distinct: Int(1) and Text("1") never collide.
-- Build a small histogram by writing through numeric keys.
hist>n;m=mmap;m=mset m 1 10;m=mset m 2 20;m=mset m 3 30;r=mget m 2;?r{n v:v;_:-1}
-- mhas works with numeric keys.
has-key>b;m=mmap;m=mset m 42 "answer";mhas m 42
-- mdel works with numeric keys.
del-key>n;m=mmap;m=mset m 1 100;m=mset m 2 200;m=mdel m 1;len (mkeys m)
-- mkeys returns L n for a numeric-keyed map.
key-count>n;m=mmap;m=mset m 1 0;m=mset m 2 0;m=mset m 3 0;ks=mkeys m;len ks
-- Iteration is deterministic via sorted mkeys.
sorted-keys>t;m=mmap;m=mset m 3 0;m=mset m 1 0;m=mset m 2 0;ks=srt (mkeys m);fmt "{};{};{}" (str (at ks 0)) (str (at ks 1)) (str (at ks 2))
-- run: hist
-- out: 20
-- run: has-key
-- out: true
-- run: del-key
-- out: 1
-- run: key-count
-- out: 3
-- run: sorted-keys
-- out: 1;2;3