I could use something like this: void main() { int[string] x = ["foo":1]; int[string] y = ["bar":1]; assert("bar" in lazyHash(x, y)); }
Essentially it would turn into lazy 'in' checks, meaning first opIn_r would be called for 'x', and then for 'y'. Otherwise it might be expensive to have to create a new hash that has all the keys and values of other hashes. Has anyone ever implemented this?