Lionel Parreaux is a Ph.D. candidate at EPFL working with Christoph Koch on programming languages, compilers, and database technology. After falling in love with Scala's flexibility and expressive power, Lionel set out to create Squid, a type-safe metaprogramming and compilation framework for Scala. Squid joins theory and practice to unlock the great promises of multi-stage programming, advanced compiler techniques, and domain-specific optimization. The core of Squid's type system was presented at POPL 2018, and papers on applications of Squid have been published at GPCE 2017 (receiving best paper award) and ECOOP 2019. Lionel interned at Microsoft Research Cambridge in 2018, where he started a collaboration with Simon Peyton Jones on a novel graph-based intermediate representation for optimizing functional programs.