Fix #1109 - allow empty if or else branches

This changesets allow empty if or else branches:

if true {
} else {
}

It works by emitting on the parser stack an AST node that doesn't
do anything (a no-op). This allows the less intrusive code
as no part of the if evaluation code has been touched.

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/puppet/parser/ast/nop.rb b/lib/puppet/parser/ast/nop.rb
new file mode 100644
index 000000000..ea5232043
--- /dev/null
+++ b/lib/puppet/parser/ast/nop.rb
@@ -0,0 +1,11 @@
+require 'puppet/parser/ast/branch'
+
+class Puppet::Parser::AST
+    # This class is a no-op, it doesn't produce anything
+    # when evaluated, hence it's name :-)
+    class Nop < AST::Leaf
+        def evaluate(scope)
+            # nothing to do
+        end
+    end
+end