diff options
Diffstat (limited to 'prolog.html.markdown')
| -rw-r--r-- | prolog.html.markdown | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/prolog.html.markdown b/prolog.html.markdown index 7a18a144..4f3984c7 100644 --- a/prolog.html.markdown +++ b/prolog.html.markdown @@ -104,7 +104,7 @@ magicNumber(42). ?- plus(1, 2, 3). % True ?- plus(1, 2, X). % X = 3 because 1+2 = X. ?- plus(1, X, 3). % X = 2 because 1+X = 3. -?- plus(X, 2, 3). % X = 1 because X+1 = 3. +?- plus(X, 2, 3). % X = 1 because X+2 = 3. ?- plus(X, 5, Y). % Error - although this could be solved, % the number of solutions is infinite, % which most predicates try to avoid. @@ -230,14 +230,14 @@ nearby3(X,Y) :- nearby2(X,Y). % Here is the structured comment declaration for nearby3: -%% nearby3(+X:Int, +Y:Int) is semidet. +%% nearby3(+X:Int, +Y:Int) is semideterministic. %% nearby3(+X:Int, -Y:Int) is multi. %% nearby3(-X:Int, +Y:Int) is multi. % For each variable we list a type. The + or - before the variable name % indicates if the parameter is bound (+) or free (-). The word after % "is" describes the behaviour of the predicate: -% semidet - can succeed once or fail +% semideterministic - can succeed once or fail % ( Two specific numbers are either nearby or not ) % multi - can succeed multiple times but cannot fail % ( One number surely has at least 3 nearby numbers ) @@ -267,8 +267,8 @@ character(darthVader). % Creates atom value darthVader % Note that below, writeln is used instead of print because print is % intended for debugging. -%% countTo(+X:Int) is det. -%% countUpTo(+Value:Int, +Limit:Int) is det. +%% countTo(+X:Int) is deterministic. +%% countUpTo(+Value:Int, +Limit:Int) is deterministic. countTo(X) :- countUpTo(1,X). countUpTo(Value, Limit) :- Value = Limit, writeln(Value), !. countUpTo(Value, Limit) :- Value \= Limit, writeln(Value), @@ -281,7 +281,7 @@ countUpTo(Value, Limit) :- Value \= Limit, writeln(Value), % IF test. If Value = Limit fails the second declaration is run. % There is also a more elegant syntax. -%% countUpTo2(+Value:Int, +Limit:Int) is det. +%% countUpTo2(+Value:Int, +Limit:Int) is deterministic. countUpTo2(Value, Limit) :- writeln(Value), Value = Limit -> true ; ( NextValue is Value+1, @@ -294,14 +294,14 @@ countUpTo2(Value, Limit) :- writeln(Value), % called a "failure-driven loop" to do this, but newer ones use a higher % order function. -%% countTo2(+X:Int) is det. +%% countTo2(+X:Int) is deterministic. countTo2(X) :- forall(between(1,X,Y),writeln(Y)). ?- countTo2(10). % Outputs 1 to 10 % Lists are given in square brackets. Use memberchk to check membership. % A group is safe if it doesn't include Joker or does include Batman. -%% safe(Group:list(atom)) is det. +%% safe(Group:list(atom)) is deterministic. safe(Group) :- memberchk(joker, Group) -> memberchk(batman, Group) ; true. ?- safe([robin]). % True |