Standardize visitors

Add a parent visitor to visit each of the fields on visitors. Then add a MatchVisitor that transforms into a Ruby pattern matching expression.

lib/syntax_tree.rb

@@ -11,7 +11,9 @@
 require_relative "syntax_tree/parser"
 require_relative "syntax_tree/version"
 require_relative "syntax_tree/visitor"
+require_relative "syntax_tree/visitor/field_visitor"
 require_relative "syntax_tree/visitor/json_visitor"
+require_relative "syntax_tree/visitor/match_visitor"
 require_relative "syntax_tree/visitor/pretty_print_visitor"
 
 # If PrettyPrint::Align isn't defined, then we haven't gotten the updated

lib/syntax_tree/cli.rb

@@ -103,7 +103,7 @@ def failure
     # An action of the CLI that prints out the doc tree IR for the given source.
     class Doc < Action
       def run(handler, filepath, source)
-        formatter = Formatter.new([])
+        formatter = Formatter.new(source, [])
         handler.parse(source).format(formatter)
         pp formatter.groups.first
       end
@@ -116,6 +116,26 @@ def run(handler, filepath, source)
       end
     end
 
+    # An action of the CLI that converts the source into its equivalent JSON
+    # representation.
+    class Json < Action
+      def run(handler, filepath, source)
+        object = Visitor::JSONVisitor.new.visit(handler.parse(source))
+        puts JSON.pretty_generate(object)
+      end
+    end
+
+    # An action of the CLI that outputs a pattern-matching Ruby expression that
+    # would match the input given.
+    class Match < Action
+      def run(handler, filepath, source)
+        formatter = Formatter.new(source, [])
+        Visitor::MatchVisitor.new(formatter).visit(handler.parse(source))
+        formatter.flush
+        puts formatter.output.join
+      end
+    end
+
     # An action of the CLI that formats the input source and writes the
     # formatted output back to the file.
     class Write < Action
@@ -154,6 +174,12 @@ def run(handler, filepath, source)
       #{Color.bold("stree format [OPTIONS] [FILE]")}
         Print out the formatted version of the given files
 
+      #{Color.bold("stree json [OPTIONS] [FILE]")}
+        Print out the JSON representation of the given files
+
+      #{Color.bold("stree match [OPTIONS] [FILE]")}
+        Print out a pattern-matching Ruby expression that would match the given files
+
       #{Color.bold("stree help")}
         Display this help message
 
@@ -201,6 +227,10 @@ def run(argv)
             Debug.new
           when "doc"
             Doc.new
+          when "j", "json"
+            Json.new
+          when "m", "match"
+            Match.new
           when "f", "format"
             Format.new
           when "w", "write"