maps - operations on maps and objects.
Reading a missing key gives null, which is indistinguishable from a null stored on purpose: Has answers that question, Get gives a default.
¶Has = fn(m, k)source
Has reports whether m holds the key k.
¶Get = fn(m, k, def)source
Get returns m[k], or def if the key is absent.
¶Keys = fn(m)source
Keys returns the keys of m. Works on objects too, where they are the names of the fields.
¶Values = fn(m)source
Values returns the values of m, in the same order as Keys.
¶Len = fn(m)source
Len returns the number of entries.
¶Each = fn(m, f)source
Each calls f(key, value) for every entry.
¶Merge = fn(a, b)source
Merge returns a new map with the entries of a and b, those of b winning.
¶Equal = fn(a, b)source
Equal reports whether two maps hold the same entries.