Extend delete function for strings and hashes

Previous to this commit, the delete function only acted on
arrays. This commit adds the same functionality for hashes and strings
in the obvious way: delete(h, k) would delete the k key from the h
hash and delete(s, sub) would delete all instances of the sub
substring from the s string.

2 files changed, 43 insertions, 12 deletions

diff --git a/lib/puppet/parser/functions/delete.rb b/lib/puppet/parser/functions/delete.rb
index ab8f75b..f814344 100644
--- a/lib/puppet/parser/functions/delete.rb
+++ b/lib/puppet/parser/functions/delete.rb
@@ -3,31 +3,43 @@
 #
 
 # TODO(Krzysztof Wilczynski): We need to add support for regular expression ...
-# TODO(Krzysztof Wilczynski): Support for strings and hashes too ...
 
 module Puppet::Parser::Functions
   newfunction(:delete, :type => :rvalue, :doc => <<-EOS
-Deletes a selected element from an array.
+Deletes all instances of a given element from an array, substring from a
+string, or key from a hash.
 
 *Examples:*
 
-    delete(['a','b','c'], 'b')
+    delete(['a','b','c','b'], 'b')
+    Would return: ['a','c']
 
-Would return: ['a','c']
+    delete({'a'=>1,'b'=>2,'c'=>3}, 'b')
+    Would return: {'a'=>1,'c'=>3}
+
+    delete('abracadabra', 'bra')
+    Would return: 'acada'
     EOS
   ) do |arguments|
 
     if (arguments.size != 2) then
       raise(Puppet::ParseError, "delete(): Wrong number of arguments "+
-        "given #{arguments.size} for 2")
+        "given #{arguments.size} for 2.")
     end
 
-    a = arguments[0]
+    collection = arguments[0]
     item = arguments[1]
 
-    a.delete(item)
-    a
-
+    case collection
+    when Array, Hash
+      collection.delete item
+    when String
+      collection.gsub! item, ''
+    else
+      raise(TypeError, "delete(): First argument must be an Array, " +
+            "String, or Hash. Given an argument of class #{collection.class}.")
+    end
+    collection
   end
 end
 
diff --git a/spec/unit/puppet/parser/functions/delete_spec.rb b/spec/unit/puppet/parser/functions/delete_spec.rb
index 0549232..2f29c93 100755
--- a/spec/unit/puppet/parser/functions/delete_spec.rb
+++ b/spec/unit/puppet/parser/functions/delete_spec.rb
@@ -8,12 +8,31 @@ describe "the delete function" do
     Puppet::Parser::Functions.function("delete").should == "function_delete"
   end
 
-  it "should raise a ParseError if there is less than 1 arguments" do
+  it "should raise a ParseError if there are fewer than 2 arguments" do
     lambda { scope.function_delete([]) }.should( raise_error(Puppet::ParseError))
   end
 
-  it "should delete an item from an array" do
-    result = scope.function_delete([['a','b','c'],'b'])
+  it "should raise a ParseError if there are greater than 2 arguments" do
+    lambda { scope.function_delete([[], 'foo', 'bar']) }.should( raise_error(Puppet::ParseError))
+  end
+
+  it "should raise a TypeError if a number is passed as the first argument" do
+    lambda { scope.function_delete([1, 'bar']) }.should( raise_error(TypeError))
+  end
+
+  it "should delete all instances of an element from an array" do
+    result = scope.function_delete([['a','b','c','b'],'b'])
     result.should(eq(['a','c']))
   end
+
+  it "should delete all instances of a substring from a string" do
+    result = scope.function_delete(['foobarbabarz','bar'])
+    result.should(eq('foobaz'))
+  end
+
+  it "should delete a key from a hash" do
+    result = scope.function_delete([{ 'a' => 1, 'b' => 2, 'c' => 3 },'b'])
+    result.should(eq({ 'a' => 1, 'c' => 3 }))
+  end
+
 end