5.4.1.2 Predefined functions on dicts

Dicts currently define the following reserved functions:

get(?Key)

Same as Dict.Key, but maps to get_dict/3 instead of get_dict_ex/3. This implies that the function evaluation fails silently if Key does not appear in Dict. See also :</2, which can be used to test for existence and unify multiple key values from a dict. For example:

?- write(t{a:x}.get(a)).
x
?- write(t{a:x}.get(b)).
false.

put(+New)

Evaluates to a new dict where the key-values in New replace or extend the key-values in the original dict. See put_dict/3.

put(+KeyPath, +Value)

Evaluates to a new dict where the KeyPath-Value replaces or extends the key-values in the original dict. KeyPath is either a key or a term KeyPath/Key,^{151Note that we do not use the '.' functor here, because the ./2 would evaluate.} replacing the value associated with Key in a sub-dict of the dict on which the function operates. See put_dict/4. Below are some examples:

?- A = _{}.put(a, 1).
A = _G7359{a:1}.

?- A = _{a:1}.put(a, 2).
A = _G7377{a:2}.

?- A = _{a:1}.put(b/c, 2).
A = _G1395{a:1, b:_G1584{c:2}}.

?- A = _{a:_{b:1}}.put(a/b, 2).
A = _G1429{a:_G1425{b:2}}.

?- A = _{a:1}.put(a/b, 2).
A = _G1395{a:_G1578{b:2}}.