Prolog - Built-In Predicates

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In Prolog, we have seen the user defined predicates in most of the cases, but there are many built-in-predicates as well. There are mainly following types of built-in predicates as given below −

• Identifying terms

• Decomposing structures

• Collecting all solutions

• Mathematical

• Scientific

Identifying Terms Predicates Group

So this is the list of some predicates that are falls under the identifying terms group −

Decomposing Structures

Now we will see, another group of built-in predicates, that is Decomposing structures. We have seen the identifying terms before. So when we are using compound structures we cannot use a variable to check or make a functor. It will return error. So functor name cannot be represented by a variable.

Error

| ?- X = tree, Y = X(maple).
uncaught exception: error(syntax_error('user_input:6 (char:16) . or operator expected after expression'),read_term/3)
| ?- 

Decomposing structure predicates are used to check Functors of terms. Following is the list of important decomposing structures predictates.

Collecting All Solutions

Now let us see the third category called the collecting all solutions, that falls under built-in predicates in Prolog.

We have seen that to generate all of the given solutions of a given goal using the semicolon in the prompt. So here is an example of it.

Example

| ?- member(X, [1,2,3,4]).

X = 1 ? ;

X = 2 ? ;

X = 3 ? ;

X = 4

(16 ms) yes
| ?- 

Sometimes, we need to generate all of the solutions to some goal within a program in some AI related applications. So there are three built-in predicates that will help us to get the results. These predicates are as follows −

These three predicates take three arguments, so we have written /3 after the name of the predicates.

These are also known as meta-predicates. These are used to manipulate Prolog's Proof strategy.

Mathematical Predicates

Following are the mathematical predicates −

Scientific Predicates

Following are the scientific predicates −