rachit-cc

A toy compiler for a simplified imperative language (SIL) written Rust.

Here is an example of a SIL program that recursively calculates the Fibonacci numbers:

# Compute the x'th Fibonacci number.
def fib(x) {
  if (x < 3) {
    return 1
  }
  else {
    return fib(x-1)+fib(x-2)
  }
}

# This expression will compute the 40th number.
fib(40)

Visualized with Python syntax highlighting for readability

And here are all the supported keywords in SIL:

def let if else while return break continue true false

Planned Features

• Handwritten table/switch driven lexer (also known as a scanner or tokenizer) ✅
• Handwritten Recursive Descent parser
• Code generation to ARM assembly
• Language support for floating point numbers and booleans, basic arithmetic operators, mutable variables, function definitions and calls, conditionals, and while loops
  • A boolean is just a floating point -> 1.0 for true and 0.0 for false
• Optimizations like trivial constant folding (to-do: flesh out all optimizations)
• 100% unit test coverage (with GitHub continuous integration to test/build the Rust project on commit) ✅

Low-Priority Future Improvements

• Support for more data types other than floating points (like integers, strings, and arrays)
• A backend for LLVM / interfacing with the LLVM API to generate optimized IR

Sources

The syntax is loosely inspired by the Decaf language reference used in CS 432 and CS 630 at James Madison University.

"Crafting Interpreters" by Robert Nystrom https://craftinginterpreters.com/

"Kaleidoscope: Implementing a Language with LLVM" https://llvm.org/docs/tutorial/MyFirstLanguageFrontend/index.html