1 files changed, 21 insertions, 0 deletions
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
index 556b5ede3c..181dca4b71 100644
--- a/guides/source/active_support_core_extensions.md
+++ b/guides/source/active_support_core_extensions.md
@@ -248,6 +248,13 @@ end
 @person.try { |p| "#{p.first_name} #{p.last_name}" }
 ```
 
+Note that `try` will swallow no-method errors, returning nil instead. If you want to protect against typos, use `try!` instead:
+
+```ruby
+@number.try(:nest)  # => nil
+@number.try!(:nest) # NoMethodError: undefined method `nest' for 1:Fixnum
+```
+
 NOTE: Defined in `active_support/core_ext/object/try.rb`.
 
 ### `class_eval(*args, &block)`
@@ -1703,6 +1710,20 @@ The method `parameterize` normalizes its receiver in a way that can be used in p
 "Kurt Gödel".parameterize # => "kurt-godel"
 ```
 
+To preserve the case of the string, set the `preserve_case` argument to true. By default, `preserve_case` is set to false.
+
+```ruby
+"John Smith".parameterize(preserve_case: true) # => "John-Smith"
+"Kurt Gödel".parameterize(preserve_case: true) # => "Kurt-Godel"
+```
+
+To use a custom separator, override the `separator` argument.
+
+```ruby
+"John Smith".parameterize(separator: "_") # => "john\_smith"
+"Kurt Gödel".parameterize(separator: "_") # => "kurt\_godel"
+```
+
 In fact, the result string is wrapped in an instance of `ActiveSupport::Multibyte::Chars`.
 
 NOTE: Defined in `active_support/core_ext/string/inflections.rb`.