[ruby/prism] Provide heredoc? queries

https://github.com/ruby/prism/commit/e148e8fe6a

lib/prism/node_ext.rb

@@ -14,8 +14,49 @@ module Prism
     end
   end
 
+  class InterpolatedMatchLastLineNode < Node
+    include RegularExpressionOptions
+  end
+
+  class InterpolatedRegularExpressionNode < Node
+    include RegularExpressionOptions
+  end
+
+  class MatchLastLineNode < Node
+    include RegularExpressionOptions
+  end
+
+  class RegularExpressionNode < Node
+    include RegularExpressionOptions
+  end
+
   private_constant :RegularExpressionOptions
 
+  module HeredocQuery # :nodoc:
+    # Returns true if this node was represented as a heredoc in the source code.
+    def heredoc?
+      opening&.start_with?("<<")
+    end
+  end
+
+  class InterpolatedStringNode < Node
+    include HeredocQuery
+  end
+
+  class InterpolatedXStringNode < Node
+    include HeredocQuery
+  end
+
+  class StringNode < Node
+    include HeredocQuery
+  end
+
+  class XStringNode < Node
+    include HeredocQuery
+  end
+
+  private_constant :HeredocQuery
+
   class FloatNode < Node
     # Returns the value of the node as a Ruby Float.
     def value
@@ -37,18 +78,6 @@ module Prism
     end
   end
 
-  class InterpolatedMatchLastLineNode < Node
-    include RegularExpressionOptions
-  end
-
-  class InterpolatedRegularExpressionNode < Node
-    include RegularExpressionOptions
-  end
-
-  class MatchLastLineNode < Node
-    include RegularExpressionOptions
-  end
-
   class RationalNode < Node
     # Returns the value of the node as a Ruby Rational.
     def value
@@ -56,10 +85,6 @@ module Prism
     end
   end
 
-  class RegularExpressionNode < Node
-    include RegularExpressionOptions
-  end
-
   class ConstantReadNode < Node
     # Returns the list of parts for the full name of this constant.
     # For example: [:Foo]

test/prism/ruby_api_test.rb

@@ -103,6 +103,18 @@ module Prism
       assert_equal 7, location.end_character_column
     end
 
+    def test_heredoc?
+      refute parse_expression("\"foo\"").heredoc?
+      refute parse_expression("\"foo \#{1}\"").heredoc?
+      refute parse_expression("`foo`").heredoc?
+      refute parse_expression("`foo \#{1}`").heredoc?
+
+      assert parse_expression("<<~HERE\nfoo\nHERE\n").heredoc?
+      assert parse_expression("<<~HERE\nfoo \#{1}\nHERE\n").heredoc?
+      assert parse_expression("<<~`HERE`\nfoo\nHERE\n").heredoc?
+      assert parse_expression("<<~`HERE`\nfoo \#{1}\nHERE\n").heredoc?
+    end
+
     private
 
     def parse_expression(source)