Implements, in PLT Redex, the sequential $C$-machine and the $P(CEK)$-machine from The Semantics of Future.

• "Figure 1: The $A$-Normalized Language $\Lambda_a$" $\Rightarrow$ input-language.rkt
• "Figure 2: The Sequential $C$-machine" $\Rightarrow$ C-machine.rkt
• "Figures 7-8: The $P(CEK)$-machine" $\Rightarrow$ PCEK-machine.rkt