I second Modern compiler implementation in ML. I'd also add Types and Programming Languages by Pierce, commonly referred to as TAPL for background on type syste

I second Modern compiler implementation in ML. I'd also add Types and Programming Languages by Pierce, commonly referred to as TAPL for background on type systems. https://www.cis.upenn.edu/~bcpierce/tapl/ https://www.cis.upenn.edu/~bcpierce/tapl/