Code for my experiments at writing a C compiler in Python.
It compiles to LLVM Intermediate Representation and handles if statements, for loops, function definitions and calls as well as basic operations.
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The goal was to figure out how a compiler works. I feel like I achieved a good part of this, although you could spend years writing a compiler.
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I do not consider the code very clean. I kinda like some of the hacks in it but you might not share these feelings.
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The hard part for me was coming up with the grammar on my own, because I was trying to force these two incompatible things:
- I wanted a simple parser (like the one I have).
- I wanted a clean, easy-to-read grammar (unlike the one I have).
One of the reasons is that my parser does not handle left-recursion.
About the code:
- I don't really have a separate lexer step. I did not really feel it was necessary with the design I chose.
- My parser does not give explicit errors. Though it's not straightforward to give good error messages, some improvements would definitely help.
You want to learn how to write a C compiler
This is probably not the best repo for this.
I got you covered though with this great tutorial series:
https://norasandler.com/2017/11/29/Write-a-Compiler.html
I stole examples and the .c test cases files from there and deleted the ones that I found too annoying to implement.