If you use one of the free LLM based tools such as ChatGPT, Bard, Claude, etc. it can give you a useful answer
ChatGPT August 3 Version
Model: GPT-3.5
Prompt
With Prolog
What does the assert/1 do ?
Completion
In Prolog, the assert/1 predicate is used to dynamically add new facts or clauses to the knowledge base during the runtime of a Prolog program. It allows you to insert new predicates or rules into the program’s database of facts and rules. The syntax for assert/1 is:
assert(Fact_or_Rule).
Here, Fact_or_Rule can be either a single fact (predicate) or a rule (predicate with a body). The assert/1 predicate takes this fact or rule and adds it to the knowledge base, making it available for subsequent queries and rule evaluation.
For example, let’s say you have a Prolog program that defines a few facts and rules related to animals:
animal(cat).
animal(dog).
mammal(X) :- animal(X), not(bird(X)).
You can use assert/1 to dynamically add new facts or rules. If you run the following query:
?- assert(animal(elephant)).
The animal(elephant) fact will be added to the knowledge base, and from that point on, you can query:
?- animal(elephant).
true.
It’s important to note that the changes made with assert/1 are usually temporary and only affect the current session. If you restart the Prolog interpreter, the added facts and rules will not persist unless you save them to a file and load them back when restarting.
Additionally, in some Prolog implementations, there might be other predicates like retract/1 or retractall/1 that allow you to remove facts or rules from the knowledge base. These predicates provide a way to manage and modify the dynamically asserted information.
You should work your way through Learn Prolog Now! for more details and a structured learning path.