Add RubyVM::AST#pretty_print

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66140 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 39 insertions, 0 deletions

diff --git a/lib/pp.rb b/lib/pp.rb
index 85401c8aa6..bb504bc1b4 100644
--- a/lib/pp.rb
+++ b/lib/pp.rb
@@ -514,6 +514,36 @@ class MatchData # :nodoc:
   end
 end
 
+class RubyVM::AbstractSyntaxTree::Node
+  def pretty_print_children(q, names = [])
+    children.zip(names) do |c, n|
+      if n
+        q.breakable
+        q.text "#{n}:"
+      end
+      q.group(2) do
+        q.breakable
+        q.pp c
+      end
+    end
+  end
+
+  def pretty_print(q)
+    q.group(1, "(#{type.sub(/\ANODE_/,'')}@#{first_lineno}:#{first_column}-#{last_lineno}:#{last_column}", ")") {
+      case type
+      when "NODE_SCOPE"
+        pretty_print_children(q, %w"tbl args body")
+      when "NODE_ARGS"
+        pretty_print_children(q, %w[pre_num pre_init opt first_post post_num post_init rest kw kwrest block])
+      when "NODE_DEFN"
+        pretty_print_children(q, %w[mid body])
+      else
+        pretty_print_children(q)
+      end
+    }
+  end
+end
+
 class Object < BasicObject # :nodoc:
   include PP::ObjectMixin
 end
diff --git a/test/test_pp.rb b/test/test_pp.rb
index 5f8216dcce..01a5a409b4 100644
--- a/test/test_pp.rb
+++ b/test/test_pp.rb
@@ -194,4 +194,13 @@ class PPFileStatTest < Test::Unit::TestCase
   end
 end
 
+class PPAbstractSyntaxTree < Test::Unit::TestCase
+  AST = RubyVM::AbstractSyntaxTree
+  def test_literal
+    ast = AST.parse("1")
+    expected = "(SCOPE@1:0-1:1 tbl: [] args: nil body: (LIT@1:0-1:1 1))"
+    assert_equal(expected, PP.singleline_pp(ast, ''.dup))
+  end
+end
+
 end