Now we're going to try and get a little code snippet that calculates factorials to work. First up: lexing the <= sign! You can find the source cod… ...more

We are repeating ourselves with the SyntaxTree and TypedSyntaxTree enums. I thought the solution would be too complex, but on reflection it's fine, so… ...more

I spent ages yesterday trying to figure out how to use Rust's tracing library (and tracing-subscriber) for a very simple logging use-case. I wanted to… ...more

Now that we have the types we calculated in our syntax tree, use them to stop faking it in error messages - replace a hard-coded "integer" with the ac… ...more

We realised last time that our type checker needs to move on from just saying "yes" or "no" for whether our program is OK: we need to keep hold of the… ...more