This is a Scheme interpreter written in Haskell. I saw the tutorial "Write Yourself a Scheme in 48 Hours", then I followed this tutorial to learn Haskell. The tutorial can be find here: https://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours
I use stack tool-chain in this project, and the GHC version is 7.10.3.