+ regular expressions and alternatives

lib/parslet/atoms/transform.rb

@@ -15,4 +15,12 @@ def visit_str(str)
   def visit_sequence(parslets)
     parslets[1..-1].inject(parslets[0]) { |a,p| a >> p }
   end
+
+  def visit_re(match)
+    Parslet.match(match)
+  end
+
+  def visit_alternative(parslets)
+    parslets[1..-1].inject(parslets[0]) { |a,p| a | p }
+  end
 end

spec/parslet/atoms/transform_spec.rb

@@ -9,30 +9,57 @@
     it "should transform all inputs onto itself"  
   end
 
-  class ModifyAll < Parslet::Atoms::Transform
-    def visit_str(s)
-      super(s.reverse)
-    end
-    def visit_sequence(seq)
-      super(seq.reverse)
-    end
-  end
+  class ModifyAll < Parslet::Atoms::Transform; end
   describe ModifyAll do
     subject { ModifyAll.new }
     def apply(grammar)
       subject.apply(grammar)
     end
-    
+
     context "str" do
+      class ModifyAll
+        def visit_str(s)
+          super(s.reverse)
+        end
+      end
       it "should reverse the string" do
         apply(str('foo')).should parse('oof')
       end 
     end
     context "sequence" do
+      class ModifyAll
+        def visit_sequence(seq)
+          super(seq.reverse)
+        end
+      end
       it "should reverse sequences" do
         apply(str('a') >> str('b')).should parse('ba')
       end 
     end
+    context "re" do
+      class ModifyAll
+        def visit_re(match)
+          super(match.delete('a'))
+        end
+      end
+      it "should not match a's" do
+        apply(match['ab']).should_not parse('a')
+        apply(match['ab']).should parse('b')
+      end 
+    end
+    context "alternative" do
+      class ModifyAll
+        def visit_alternative(parslets)
+          super(parslets.reverse)
+        end
+      end
+      it "should reverse priorities" do
+        apply(
+          str('foobar').as(:whole) |
+          str('foo').as(:foo) >> str('bar').as(:bar)
+        ).should parse('foobar').as(:foo => 'foo', :bar => 'bar')
+      end 
+    end
   end
 
 end