You can copy them in a pure functional program if the function AST you're transporting is sufficiently expressive, because the values of the unbound free variables in pure FP are available at the point where the function is defined, so can be inlined into it, and included in its hash.
But when it's not pure FP, then indeed you can't copy the values into the function AST, because the environment at the point of each call to the function is what matters.
(The pipe stuff is just for making it more efficient, and handling black boxes which sit outside the paradigm of concrete values, things like I/O monads and devices).
Comments
You can copy them in a pure functional program if the function AST you're transporting is sufficiently expressive, because the values of the unbound free variables in pure FP are available at the point where the function is defined, so can be inlined into it, and included in its hash.
But when it's not pure FP, then indeed you can't copy the values into the function AST, because the environment at the point of each call to the function is what matters.
(The pipe stuff is just for making it more efficient, and handling black boxes which sit outside the paradigm of concrete values, things like I/O monads and devices).