Merge 5615da920f into b7d4a62ecb

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1554 TILs and counting..._
+_1555 TILs and counting..._
 
 ---
 
@@ -191,7 +191,7 @@ _1554 TILs and counting..._
 - [Aliasing An Ansible Host](devops/aliasing-an-ansible-host.md)
 - [Allow Cross-Origin Requests To Include Cookies](devops/allow-cross-origin-requests-to-include-cookies.md)
 - [Allow HTTPS Through Your UFW Firewall](devops/allow-https-through-your-ufw-firewall.md)
-- [Check For Cached Site Assocation File For iOS](devops/check-for-cached-site-association-file-for-ios.md)
+- [Check For Cached Site Association File For iOS](devops/check-for-cached-site-association-file-for-ios.md)
 - [Check The Status of All Services](devops/check-the-status-of-all-services.md)
 - [Check The Syntax Of nginx Files](devops/check-the-syntax-of-nginx-files.md)
 - [Connect To An RDS PostgreSQL Database](devops/connect-to-an-rds-postgresql-database.md)
@@ -752,7 +752,7 @@ _1554 TILs and counting..._
 - [Check If Clusters Are Upgrade Compatible](postgres/check-if-clusters-are-upgrade-compatible.md)
 - [Check If The Local Server Is Running](postgres/check-if-the-local-server-is-running.md)
 - [Check If User Role Exists For Database](postgres/check-if-user-role-exists-for-database.md)
-- [Check Table For Any Oprhaned Records](postgres/check-table-for-any-orphaned-records.md)
+- [Check Table For Any Orphaned Records](postgres/check-table-for-any-orphaned-records.md)
 - [Checking Inequality](postgres/checking-inequality.md)
 - [Checking The Type Of A Value](postgres/checking-the-type-of-a-value.md)
 - [Clear The Screen In psql](postgres/clear-the-screen-in-psql.md)
@@ -1303,6 +1303,7 @@ _1554 TILs and counting..._
 - [Question Mark Operator](ruby/question-mark-operator.md)
 - [Rake Only Lists Tasks With Descriptions](ruby/rake-only-lists-tasks-with-descriptions.md)
 - [Read The First Line From A File](ruby/read-the-first-line-from-a-file.md)
+- [Refer To Implicit Block Argument With It](ruby/refer-to-implicit-block-argument-with-it.md)
 - [Rendering ERB](ruby/rendering-erb.md)
 - [Replace The Current Process With An External Command](ruby/replace-the-current-process-with-an-external-command.md)
 - [Require Entire Gemfile In Pry Session](ruby/require-entire-gemfile-in-pry-session.md)

ruby/refer-to-implicit-block-argument-with-it.md

@@ -0,0 +1,43 @@
+# Refer To Implicit Block Argument With It
+
+One of the key features of the Ruby 3.4 release is the `it` implicit block
+argument.
+
+The vast majority of inline blocks defined in Ruby code receive a single block
+argument. Typically we name and reference a block argument explictly like so:
+
+```ruby
+items.map { |item| item * item }
+```
+
+Ruby likes to cut away excess syntax when possible. To that end, the implicit
+`it` block argument has been added. This is an identifier we can reference in
+the context of a block and its value is the current
+
+```ruby
+items = [1,2,3,4,5]
+
+squares = items.map { it * it }
+
+pp squares
+#=> [1, 4, 9, 16, 25]
+```
+
+Note: we cannot mix numbered parameters (`_1`, `_2`) with the `it` parameter.
+If we do, we'll get the following error:
+
+```ruby
+def method_using_block(a, b)
+  yield(a, b) if block_given?
+end
+
+puts method_using_block(4,5) { _2 ** _1 } #=> 625
+puts method_using_block(4,5) { _2 ** it }
+# it_block.rb:12: syntax error found (SyntaxError)
+#   10 |
+#   11 | puts method_using_block(4,5) { _2 ** _1 }
+# > 12 | ... it }
+#      |     ^~ `it` is not allowed when a numbered parameter is already used
+```
+
+[source](https://docs.ruby-lang.org/en/3.4/NEWS_md.html)