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PrologDeterm

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(Prolog) determ

Shorthand for deterministic, a predicate mode. By default, all global predicates are determ.

A deterministic clause can only produce one solution. A clause that can produce more solutions is called a non-determininistic clause, which is indicated by the keyword nondeterm.

Example of determ clauses

predicates
  determ isOdd(integer).
  determ isEven(integer).
  
clauses
  isOdd(X) IF
    (X mod 2) = 1.  
  isEven(X) IF 
    (X mod 2) = 0.

goal
  isEven(1).

Note you can declare these clauses nondeterm, but this will not give you compiler protection.

Do not confuse determ with 'knowable beforehand', also a randomly determined predicate can be determ, if it only returns one single value.

predicates
  determ isHead().
  
clauses
  isHead() IF
    random(X),
    X < 0.5 .  
goal
  isHead().

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