diff --git a/README.md b/README.md
index f3a0a13b..3fba928a 100644
--- a/README.md
+++ b/README.md
@@ -165,7 +165,7 @@ If you are the current maintainer of this gem:
  0. Ensure that tests are green: `bundle exec rake test`
  0. Bump gem version in `lib/linguist/version.rb`.  For example, [like this](https://github.com/github/linguist/commit/8d2ea90a5ba3b2fe6e1508b7155aa4632eea2985).
  0. Make a PR to github/linguist.  For example, [#1238](https://github.com/github/linguist/pull/1238).
- 0. Build a local gem: `gem build github-linguist.gemspec`
+ 0. Build a local gem: `bundle exec rake build_gem`
  0. Testing:
    0. Bump the Gemfile and Gemfile.lock versions for an app which relies on this gem
    0. Install the new gem locally
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 d2e80f64..de1f5229 100644
--- a/lib/linguist/languages.yml
+++ b/lib/linguist/languages.yml
@@ -949,6 +949,7 @@ HTML:
 
 HTML+Django:
   type: markup
+  tm_scope: text.html.django
   group: HTML
   lexer: HTML+Django/Jinja
   extensions:
@@ -957,6 +958,7 @@ HTML+Django:
 
 HTML+ERB:
   type: markup
+  tm_scope: text.html.erb
   group: HTML
   lexer: RHTML
   aliases:
@@ -967,6 +969,7 @@ HTML+ERB:
 
 HTML+PHP:
   type: markup
+  tm_scope: text.html.php
   group: HTML
   extensions:
   - .phtml
@@ -1102,6 +1105,7 @@ J:
 
 JSON:
   type: data
+  tm_scope: source.json
   group: JavaScript
   ace_mode: json
   searchable: false
@@ -1293,6 +1297,7 @@ Literate Agda:
 
 Literate CoffeeScript:
   type: programming
+  tm_scope: source.litcoffee
   group: CoffeeScript
   lexer: Text only
   ace_mode: markdown
@@ -1587,6 +1592,7 @@ Objective-C:
 
 Objective-C++:
   type: programming
+  tm_scope: source.objc++
   color: "#4886FC"
   aliases:
   - obj-c++
@@ -1829,6 +1835,7 @@ Prolog:
   extensions:
   - .pl
   - .ecl
+  - .pro
   - .prolog
 
 Propeller Spin:
@@ -2083,6 +2090,7 @@ SAS:
 
 SCSS:
   type: markup
+  tm_scope: source.scss
   group: CSS
   ace_mode: scss
   extensions:
@@ -2123,6 +2131,7 @@ Sage:
 
 Sass:
   type: markup
+  tm_scope: source.sass
   group: CSS
   extensions:
   - .sass
@@ -2597,6 +2606,7 @@ Xtend:
 
 YAML:
   type: data
+  tm_scope: source.yaml
   aliases:
   - yml
   extensions:
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)