Building your own programming language in Python3 - Part 1: LEXER

In this video we will be creating a Lexer, known to be the first component needed towards the creation of an interpreter (Lexer-Parser-Interpreter).

00:31 Theory (what is a Lexer?)
3:28 The Lexer class diagram
13:02 Running the finished program to show what it does
15:24 Creating the driver file/program
15:43 Behold the neithan++ programming language (haha!)
18:09 Coding the Token Class
26:26 A designated practice area for your code
29:53 Coding the Lexer Class
40:45 Coding the Runner/Driver function
44:41 Tokenizing numbers
55:11 Demonstrating our lexer version 1

We first try to look at the theory behind the behavior of a lexer (assigning meaning to numbers and operators through token creation). We then proceed with coding the Token and Lexer classes and use a driver program to demonstrate it's utility.

In succeeding videos, we will expand the custom language to support the use of variables, conditionals and functions.

References:
David Callanan loosely based his tutorials on this resource: