diff --git a/lib/linguist/heuristics.rb b/lib/linguist/heuristics.rb
index 21764b34..4c1bf295 100644
--- a/lib/linguist/heuristics.rb
+++ b/lib/linguist/heuristics.rb
@@ -19,6 +19,9 @@ module Linguist
         if languages.all? { |l| ["ECL", "Prolog"].include?(l) }
           result = disambiguate_ecl(data, languages)
         end
+        if languages.all? { |l| ["IDL", "Prolog"].include?(l) }
+          result = disambiguate_pro(data, languages)
+        end
         if languages.all? { |l| ["Common Lisp", "OpenCL"].include?(l) }
           result = disambiguate_cl(data, languages)
         end
@@ -51,6 +54,16 @@ module Linguist
       matches
     end
 
+    def self.disambiguate_pro(data, languages)
+      matches = []
+      if (data.include?(":-"))
+        matches << Language["Prolog"]
+      else
+        matches << Language["IDL"]
+      end
+      matches
+    end
+
     def self.disambiguate_ts(data, languages)
       matches = []
       if (data.include?("</translation>"))
diff --git a/lib/linguist/languages.yml b/lib/linguist/languages.yml
index c85fe463..4df5e3ce 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -1820,6 +1820,7 @@ Prolog:
   extensions:
   - .pl
   - .ecl
+  - .pro
   - .prolog
 
 Propeller Spin:
diff --git a/samples/Prolog/logic-problem.pro b/samples/Prolog/logic-problem.pro
new file mode 100644
index 00000000..b70120bf
--- /dev/null
+++ b/samples/Prolog/logic-problem.pro
@@ -0,0 +1,68 @@
+/**
+ * Question 1.1
+ * combiner(+Buddies, -Pairs)
+ */
+combiner([], []).
+combiner([First|Buddies], Pairs):-
+	make_pairs(First, Buddies, Pairs1),
+	combiner(Buddies, Pairs2),
+	concat(Pairs1, Pairs2, Pairs).
+
+/**
+ * make_pairs(+Buddy, +Buddies, -Pairs)
+ */
+make_pairs(Buddy, [], []).
+make_pairs(Buddy, [First|Buddies], [(Buddy, First)|Pairs]):-
+	make_pairs(Buddy, Buddies, Pairs).
+
+/**
+ * concat(+X, +Y, ?T)
+ */
+concat([], Y, Y).
+concat([P|R], Y, [P|T]):-
+	concat(R, Y, T).
+
+
+/**
+ * Question 1.2
+ * extraire(+AllPossiblePairs, +NbPairs, -Tp, -RemainingPairs)
+ */
+extraire(AllPossiblePairs, 0, [], AllPossiblePairs).
+extraire([PossiblePair|AllPossiblePairs], NbPairs, [PossiblePair|Tp], NewRemainingPairs):-
+	NbPairs > 0,
+	NewNbPairs is NbPairs - 1,
+	extraire(AllPossiblePairs, NewNbPairs, Tp, RemainingPairs),
+	not(pair_in_array(PossiblePair, Tp)),
+	delete_pair(RemainingPairs, PossiblePair, NewRemainingPairs).
+extraire([PossiblePair|AllPossiblePairs], NbPairs, Tp, [PossiblePair|RemainingPairs]):-
+	NbPairs > 0,
+	extraire(AllPossiblePairs, NbPairs, Tp, RemainingPairs),
+	pair_in_array(PossiblePair, Tp).
+
+/**
+ * delete_pair(+Pairs, +Pair, -PairsWithoutPair)
+ */
+delete_pair([], _, []).
+delete_pair([Pair|Pairs], Pair, Pairs):-!.
+delete_pair([FirstPair|Pairs], Pair, [FirstPair|PairsWithoutPair]):-
+	delete_pair(Pairs, Pair, PairsWithoutPair).
+
+/**
+ * pair_in_array(+Pair, +Pairs)
+ */
+pair_in_array((A, B), [(C, D)|Pairs]):-
+	(A == C ; B == D ; A == D ; B == C),
+	!.
+pair_in_array(Pair, [FirstPair|Pairs]):-
+	pair_in_array(Pair, Pairs).
+
+
+/**
+ * Question 1.3
+ * les_tps(+Buddies, -Tps)
+ */
+les_tps(Buddies, Tps):-
+	combiner(Buddies, PossiblePairs),
+	length(Buddies, NbBuddies),
+	NbPairs is integer(NbBuddies / 2),
+	findall(Tp, extraire(PossiblePairs, NbPairs, Tp, _), Tps).
diff --git a/test/test_heuristics.rb b/test/test_heuristics.rb
index 8bbf0695..55fb5331 100644
--- a/test/test_heuristics.rb
+++ b/test/test_heuristics.rb
@@ -65,6 +65,18 @@ class TestHeuristcs < Test::Unit::TestCase
     assert_equal Language["ECL"], results.first
   end
 
+  def test_pro_prolog_by_heuristics
+    languages = ["IDL", "Prolog"]
+    results = Heuristics.disambiguate_pro(fixture("Prolog/logic-problem.pro"), languages)
+    assert_equal Language["Prolog"], results.first
+  end
+
+  def test_pro_idl_by_heuristics
+    languages = ["IDL", "Prolog"]
+    results = Heuristics.disambiguate_pro(fixture("IDL/mg_acosh.pro"), languages)
+    assert_equal Language["IDL"], results.first
+  end
+
   def test_ts_typescript_by_heuristics
     languages = ["TypeScript", "XML"]
     results = Heuristics.disambiguate_ts(fixture("TypeScript/classes.ts"), languages)