Learn about the theory of concatenative combinators.

[aaditmshah]

We need the theory of concatenative combinators in order to implement a VM for typecasting.

[aaditmshah]

I learned that we only need six concatenative combinators for Turing completeness.

1. dup - To use items on the stack more than once.
2. drop - To ignore items on the stack.
3. swap - To rearrange items on the stack.
4. quote - To convert code into data.
5. unquote - To convert data into code.
6. append - To merge multiple quoted items.