Experiment based on https://norvig.com/lispy.html and http://norvig.com/lispy2.html

Features:

• Written in a simple subset of C++.
• NaN boxing. Basic types such as int/double are 64 bits and do not go to the heap.
• Lists, symbols, functions etc are heap allocated.
• Tail recursion optimization
• First class environments
• Supports kernel-style operatives (calls where all the arguments are passed unevaluated)
• Garbage collection based on github.com/bullno1/ugc

TODO:

• Switch to incremental GC & (auto)tune
• Optimize function calls via a stack