From 3169a43f4c24d01c64c90ab9537da284f587c726 Mon Sep 17 00:00:00 2001
From: Maksym Melnychok <maksym@yelp.com>
Date: Mon, 8 Feb 2016 07:50:35 -0800
Subject: Add dig() function

Deprecates #try_get_value()
---
 lib/puppet/parser/functions/dig.rb | 54 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 lib/puppet/parser/functions/dig.rb

(limited to 'lib/puppet/parser/functions/dig.rb')

diff --git a/lib/puppet/parser/functions/dig.rb b/lib/puppet/parser/functions/dig.rb
new file mode 100644
index 0000000..a9aa770
--- /dev/null
+++ b/lib/puppet/parser/functions/dig.rb
@@ -0,0 +1,54 @@
+#
+# dig.rb
+#
+
+module Puppet::Parser::Functions
+  newfunction(:dig, :type => :rvalue, :doc => <<-EOS
+Looks up into a complex structure of arrays and hashes and returns nil
+or the default value if nothing was found.
+
+Path is an array of keys to be looked up in data argument. The function
+will go down the structure and try to extract the required value.
+
+$data = {
+  'a' => {
+    'b' => [
+      'b1',
+      'b2',
+      'b3' ]}}
+
+$value = dig($data, ['a', 'b', '2'], 'not_found')
+=> $value = 'b3'
+
+a -> first hash key
+b -> second hash key
+2 -> array index starting with 0
+
+not_found -> (optional) will be returned if there is no value or the path
+did not match. Defaults to nil.
+
+In addition to the required "path" argument, "dig" accepts default
+argument. It will be returned if no value was found or a path component is
+missing. And the fourth argument can set a variable path separator.
+    EOS
+             ) do |arguments|
+    # Two arguments are required
+    raise(Puppet::ParseError, "dig(): Wrong number of arguments " +
+                              "given (#{arguments.size} for at least 2)") if arguments.size < 2
+
+    data, path, default = *arguments
+
+    if !(data.is_a?(Hash) || data.is_a?(Array))
+      raise(Puppet::ParseError, "dig(): first argument must be a hash or an array, " <<
+                                "given #{data.class.name}")
+    end
+
+    unless path.is_a? Array
+      raise(Puppet::ParseError, "dig(): second argument must be an array, " <<
+                                "given #{path.class.name}")
+    end
+
+    value = path.reduce(data) { |h, k| (h.is_a?(Hash) || h.is_a?(Array)) ? h[k] : break }
+    value.nil? ? default : value
+  end
+end
-- 
cgit v1.2.3