'Returning a value from a function in prolog
How do we return a value from a Prolog function that takes only one argument? Ex. leaf(V) is a function which should return a value V and it is called from a function tree(leav(V), sum)?
Solution 1:[1]
Prolog does not have function evaluation, so you will have to represent your function as a relation
f(In,Out) :- ... define the relationship between In and Out in the body ...
For example for squaring:
square(X,Y) :- Y is X*X.
?- square(12,X).
X=144
The "function symbols" in Prolog are purely denotational: they are for constructing terms:
f(x)
The above term has no inherent meaning or resolvability. It is just a term, more precisely a tree
f
|
x
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
| Solution | Source |
|---|---|
| Solution 1 | David Tonhofer |