update the video.org for episode 4

docs/videos.org

@@ -30,7 +30,8 @@ CLOSED: [2021-07-10 Sat 09:04]
 - git hooks
 ** Source tree structure
 ** =dev.org= resources and TODOs
-* Episode 3 - Overview
+* DONE Episode 3 - Overview
+CLOSED: [2021-07-19 Mon 09:41]
 ** Generic Compiler
 - [[https://www.cs.princeton.edu/~appel/modern/ml/whichver.html][Modern Compiler Implementation in ML: Basic Techniques]]
 - [[https://suif.stanford.edu/dragonbook/][Compilers: Principles, Techniques, and Tools (The Dragon Book)]]
@@ -85,6 +86,7 @@ Deducted from https://www.aosabook.org/en/llvm.html
 - Call the default =c compiler= to link the object files and generate the machine code.
 * Episode 4 - The reader
 ** What is a Parser ?
+To put it simply, Parser converts the source code to an [[https://en.wikipedia.org/wiki/Abstract_syntax_tree][AST]]
 *** Algorithms
 - LL(k)
 - LR
@@ -106,5 +108,5 @@ Read More:
   (defn main ()
     (println "Result: " (some-fn 3 8)))
 #+END_SRC
-- LL(1.5)? s
+- LL(1.5)?
 - O(n)

include/serene/reader/reader.h

@@ -88,6 +88,7 @@ public:
   Result<exprs::Ast> read();
 
   // Dumps the AST data to stdout
+  // TODO: Change the name to dump
   void toString();
 
   ~Reader();

src/serene/reader/reader.cpp

@@ -208,6 +208,8 @@ exprs::Node Reader::readList() {
   auto list = exprs::makeAndCast<exprs::List>(current_location);
 
   char c = getChar(true);
+
+  // TODO: Replace the assert with an actual check.
   assert(c == '(');
 
   bool list_terminated = false;
@@ -221,7 +223,6 @@ exprs::Node Reader::readList() {
     case ')':
       list_terminated    = true;
       list->location.end = current_location;
-
       break;
 
     default: