(#19272) Add has_element() function

It is exceptionally difficult to determine if an array contains an element matching a specific value without an iteration or loop construct.

This function is the Puppet equivalent of Array.includes?(foo) in Ruby.  The implementation is a verbatim copy of has_key() with the minor modifications needed to support arrays instead of hashes.

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/puppet/parser/functions/has_element.rb b/lib/puppet/parser/functions/has_element.rb
new file mode 100644
index 0000000..e29bbb9
--- /dev/null
+++ b/lib/puppet/parser/functions/has_element.rb
@@ -0,0 +1,28 @@
+module Puppet::Parser::Functions
+
+  newfunction(:has_element, :type => :rvalue, :doc => <<-'ENDHEREDOC') do |args|
+    Determine if an array has an element with a matching value.
+
+    Example:
+
+        $my_array = ['key_one']
+        if has_element($my_array, 'key_two') {
+          notice('we will not reach here')
+        }
+        if has_element($my_array, 'key_one') {
+          notice('this will be printed')
+        }
+
+    ENDHEREDOC
+
+    unless args.length == 2
+      raise Puppet::ParseError, ("has_element(): wrong number of arguments (#{args.length}; must be 2)")
+    end
+    unless args[0].is_a?(Array)
+      raise Puppet::ParseError, "has_element(): expects the first argument to be an array, got #{args[0].inspect} which is of type #{args[0].class}"
+    end
+    args[0].include?(args[1])
+
+  end
+
+end