* Use 64-bit integers on 64-bit platforms, just like gc and gccgo:
https://golang.org/doc/go1.1#int
* Do not use a separate length type. Instead, use uintptr everywhere a
length is expected.
Bigger hashmaps (size > 8) use multiple buckets in a chain. The lookup
code looked at multiple buckets for a lookup, but kept checking the
first bucket for key equality.
TODO: do better at it by tracking min/max values of integers. The
following straightforward code doesn't have its bounds checks removed:
for _, n := range slice {
println(n)
}
Missing features:
* keys other than strings
* more than 8 values in the hashmap
* growing a map when needed
* initial size hint
* delete(m, key)
* iterators (for range)
* initializing global maps
* ...more?
