This is a personal project in making a very simple Python interpreter for my very simple language.

FEATURES:

• simple scanner
• simple AST for use in a descent tree parser
• expressions will use reverse-polish notation
• the memory is made with a simple stack and heap system:
  • the stack will hold all of the working data
  • the heap is a map between the identifier and the value it represents, which can be updated using code
• the language is procedural
• there are only three native data types: String, Bool, Integer
• the list of keywords is very small:
  • if
  • else
  • elif
  • while
  • int
  • bool
  • string
  • return
  • fn
• the list of literals is also small:
  • true
  • false
  • any integer
  • any word (for identifiers and string literals)
• there are operators for each type of literal:
  • strings:
    • +: this concatenates two strings together
  • bool:
    • and: this is true if two bools are equal to eachother
    • or: this is false if two bools are not equal to eachother
    • not: this negates a bool
  • int:
    • binary operators:
      • +: adds two integers
      • -: takes away two integers
      • *: multiplies two integers
      • /: divides two integers
      • <: returns true if a number is less than another
      • ">": returns true if a number is greater than another
      • =: retuns true if two numbers are equal to eachother
    • unary operators:
      • -: this turns a positive integer negative and vice-versa
• the language has syntax inspired by c:
  • a semi-colon identifies the end of the statement
  • if, elif and while take a bool expressive argument in () brackets
  • after a function or control flow a {} will identify the next block of code
• there are some simple changes though:
  • arguments passed into functions will follow reverse-Polish notation style, e.g.: instead of add_two_numbers(a, b); we will use a b addd_two_numbers;
  • reassigning a variable will not use the = sign, it will instead use a colon, e.g.: instead of x = x * 4; we will use x: x 4 *;
• at the moment the standard library will be able to print to the console, however the idea is to be able to expand this in the future to make this into a more useful language