This is the first devlog for my Domain and Range calculator. I have completed making the first part of my custom AST algorithm: the tokenizer. I have used simple string parsing to separate specific terms in the expression. The algorithm handles sequence of characters (like alphabets or digits) as a single term which opens up the world to more complex and some basic and necessary functions like sqrt(), log(), trigonometric and inverse trigonometric functions. I am now going to handle some edge cases and try to functionize or shorten the collection of characters part as I have noticed that The process is same for digit and alphabets so I could potentially shorten the code. I expect this program to fit cleanly into the larger mathematical suit that I am trying to build to support most of mathematics along with support for coordinate geometry but that is something for later.