(#6787) Add `default_to` for options.

This implement support for options with default values, allowing faces to set
those values when not invoked.  This can eliminate substantial duplicate code
from actions, especially when there are face-level options in use.

Reviewed-By: Pieter van de Bruggen <pieter@puppetlabs.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/puppet/interface/option_builder.rb b/lib/puppet/interface/option_builder.rb
index 5676ec977..c87adc2c0 100644
--- a/lib/puppet/interface/option_builder.rb
+++ b/lib/puppet/interface/option_builder.rb
@@ -51,4 +51,17 @@ class Puppet::Interface::OptionBuilder
   def required(value = true)
     @option.required = value
   end
+
+  def default_to(&block)
+    block or raise ArgumentError, "#{@option} default_to requires a block"
+    if @option.has_default?
+      raise ArgumentError, "#{@option} already has a default value"
+    end
+    # Ruby 1.8 treats a block without arguments as accepting any number; 1.9
+    # gets this right, so we work around it for now... --daniel 2011-07-20
+    unless block.arity == 0 or (RUBY_VERSION =~ /^1\.8/ and block.arity == -1)
+      raise ArgumentError, "#{@option} default_to block should not take any arguments"
+    end
+    @option.default = block
+  end
 end