Merge pull request #43 from ruby-syntax-tree/pretty-print-visitor

Pretty print within a visitor

Author: kddnewton

README.md

@@ -249,6 +249,8 @@ With visitors, you only define handlers for the nodes that you need. You can fin
 * call `visit(child)` with each child that you want to visit
 * call nothing if you're sure you don't want to descend further
 
+There are a couple of visitors that ship with Syntax Tree that can be used as examples. They live in the [lib/syntax_tree/visitor](lib/syntax_tree/visitor) directory.
+
 ### visit_method
 
 When you're creating a visitor, it's very easy to accidentally mistype a visit method. Unfortunately, there's no way to tell Ruby to explicitly override a parent method, so it would then be easy to define a method that never gets called. To mitigate this risk, there's `Visitor.visit_method(name)`. This method accepts a symbol that is checked against the list of known visit methods. If it's not in the list, then an error will be raised. It's meant to be used like:

lib/syntax_tree.rb

@@ -11,8 +11,8 @@
 require_relative "syntax_tree/parser"
 require_relative "syntax_tree/version"
 require_relative "syntax_tree/visitor"
-
-require_relative "syntax_tree/json_visitor"
+require_relative "syntax_tree/visitor/json_visitor"
+require_relative "syntax_tree/visitor/pretty_print_visitor"
 
 # If PrettyPrint::Align isn't defined, then we haven't gotten the updated
 # version of prettyprint. In that case we'll define our own. This is going to