Implementing a small functional language with a combinator graph reduction engine

• implement if based on bools
• implement all lispkit primops
• have 'it' in the repl
• provide :l, :r and :q in repl
• add define to repl
• compile SEpxr to lambda terms
• build eval based on lambda terms
• eval can throw exceptions
• support closures with lexical / static scope
• write regression test suite

• implement letrec in lambda term evaluator
• compile lambda to SKI combinators
• write graph reduction for combinator graphs
• reimplement P combinator from my ancient webLisp