From 701d3d912c3f440201a469263b775cf8f84b3ca0 Mon Sep 17 00:00:00 2001
From: Sameer Rahmani <lxsameer@gnu.org>
Date: Wed, 18 May 2022 20:19:18 +0100
Subject: [PATCH] Finish up episode 6

---
 docs/videos.org | 105 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 104 insertions(+), 1 deletion(-)

diff --git a/docs/videos.org b/docs/videos.org
index a2c6363..2ef3b6f 100644
--- a/docs/videos.org
+++ b/docs/videos.org
@@ -177,7 +177,8 @@ CLOSED: [2022-04-09 Sat 11:24]
 - boundp
 - More at https://www.gnu.org/software/emacs/manual/html_node/elisp/Type-Predicates.html
 ** type-of
-* Episode 5 - Lists
+* DONE Episode 5 - Lists
+CLOSED: [2022-05-18 Wed 12:40]
 ** What is a list?
 - Not a primitive type
 - A linked list made out of cons cells
@@ -310,3 +311,105 @@ digraph {
 #+END_SRC
 
 * Episode 6 - Property & Association Lists
+** I have an idea
+- Develop *FG42* on stream
+- I'll announce the date and time on:
+  + Twitter: @lxsameer
+  + Youtube Community (maybe)
+
+** eq vs equal
+- ~eq~ checks whether two objects are the same
+- ~equal~ checks whether two objects have similar structure and content.
+
+** Property List (plist)
+- Is a list of paired elements
+- Each of the pairs associates a property name with a property or value
+- The order of the property names (keys) is not significant
+- Keys must be unique
+- Emacs uses plists to store text properties and symbol properties
+
+*** Examples
+#+BEGIN_SRC emacs-lisp
+  (setq x '(:a 1 "b" 2 c 3 :d ("foo" "bar") :j nil))
+  x
+#+END_SRC
+
+*** Functions
+- ~plist-get~ or ~lax-plist-get~
+#+BEGIN_SRC emacs-lisp
+  (plist-get x :a)
+  (plist-get x "b")
+  (lax-plist-get x "b")
+#+END_SRC
+
+- ~plist-put~ or ~lax-plist-put~
+#+BEGIN_SRC emacs-lisp
+  (plist-put x :z 325)
+  (plist-put x :z 10)
+  (lax-plist-put x "b" 20)
+#+END_SRC
+
+- ~plist-member~
+#+BEGIN_SRC emacs-lisp
+  (plist-get x :j)
+  (plist-get x :g)
+  (plist-member x :j)
+  (plist-member x :g)
+#+END_SRC
+
+** An example use case of plist
+#+BEGIN_SRC emacs-lisp
+  (defun foo (&rest args)
+    (message "ARGS: %s" args)
+    (plist-get args :name))
+
+  (foo :age 20 :name 'bob "blah" '(12 34 4))
+#+END_SRC
+
+** Association List (alist)
+- It is a list of cons cells called associations
+- Mapping some keys to some values
+- The ~CAR~ of each cons cell is the key, and the ~CDR~ is the associated value
+- The order of associations matters
+
+*** Examples
+#+BEGIN_SRC emacs-lisp
+  (setq y '((:a . 1) ("b" . 2) (c . 3) (:d "foo" "bar")))
+  y
+#+END_SRC
+
+*** Functions
+- ~assoc~
+#+BEGIN_SRC emacs-lisp
+  (assoc :a y)
+  (assoc "b" y)
+#+END_SRC
+
+- ~rassoc~
+#+BEGIN_SRC emacs-lisp
+  (rassoc 1 y)
+  (rassoc 3 y)
+#+END_SRC
+
+- ~assq~
+#+BEGIN_SRC emacs-lisp
+  (assq :a y)
+  (assq "b" y)
+#+END_SRC
+
+- ~alist-get~
+#+BEGIN_SRC emacs-lisp
+  (alist-get :a y)
+  (alist-get :z y "blah")
+#+END_SRC
+
+- ~cons~
+#+BEGIN_SRC emacs-lisp
+  (setq y1 (cons '(:z . 31) y))
+  (assoc :z y1)
+#+END_SRC
+
+** References
+- https://www.gnu.org/software/emacs/manual/html_node/elisp/Association-Lists.html
+- https://www.gnu.org/software/emacs/manual/html_node/elisp/Plist-Access.html
+- https://www.gnu.org/software/emacs/manual/html_node/elisp/Plists-and-Alists.html